No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Effect of High Voltage Stimulation on Blood Flow in the Rat Hind Limb
Abstract
The purpose of this study was to test the effect of high voltage stimulation (HVS) on blood flow velocity (BFV) in the rat hind limb. A 20-MHz pulsed Doppler device was used to measure BFV changes in the femoral artery of 20 anesthetized rats after electrical stimulation. The animals were stimulated under the following conditions: four different pulse rates, changes in stimulus voltage, and changes in polarity. Blood flow velocity also was measured in the unstimulated hind limb. Although each of the four pulse rates caused significant increases in BFV, the 20-pulse-per-second rate produced BFV increases significantly greater than the other three pulse rates. The BFV changes, on the average, occurred less than 1 minute from the onset of stimulation and lasted up to 14 minutes after the cessation of the stimulation. The BFV increased with increases in voltage intensity. Both the positive and negative poles elicited significant increases in BFV, but the negative pole produced the greatest increases. Blood flow in the unstimulated hind limb was unchanged after stimulation. This study indicates that HVS of muscle does cause significant increases in blood flow to the stimulated rat hind limb.
... Los investigadores han demostrado la presencia de sistemas bioeléctricos endógenos (Klot et al.,1996;Charman, 1990) y en la literatura se encuentran referencias de los efectos de estimulación eléctrica en úlceras generadas por presión, por insuficiencia vascular, por trauma, por diabetes, o por cirugías, entre otras (Sandoval et al., 2007;Poltawski et al., 2008a, b;2009). La estimulación eléctrica en la piel ha sido utilizada como bactericida (Nelson et al., 1999;Kincaid et al., 1989) para incrementar el flujo sanguíneo (Mohr et al., 1987;Goldman et al., 2001) y promover la cicatrización (Im et al., 1990;Brown et al., 1987, Chi-Sing et al., 1996. La AED ha Electrodermal activity Electrodermal activity Electrodermal activity Electrodermal activity ----a review a review a review a review ...
... References about the effects of electrical stimulation concerning ulcers generated by pressure, vascular insufficiency, trauma, diabetes, surgery abound in the literature (Sandoval et al., 2007;Poltawski, 2008 a, b;2009). Electrical stimulation of the skin has been used as a bactericide (Nelson et al., 1999;Kincaid et al., 1989) to increase blood flow (Mohr et al., 1987;Goldman et al., 2001) and to promote healing (Im et al., 1990;Brown et al., 1987, Chi-Sing, 1996. Electrodermal activity (EDA) has also been studied and widely used in psychology as a stress level indicator (Clements and Turpin, 2000), including neurosis (Norris, 2007). ...
... They observed that granulocytes increased by 63.5% in people who received maximum stimulation compared to 44.7% of cells which did not receive stimulation. Mohr et al., (1987) used EHV for rats' hind limb blood flow, using three frequencies (2.20, 80 and 120 pps) and both polarities. A significant increase in blood flow speed was found for each pulse at both polarities. ...
the electricity in living tissue was widely studied around the 19th century. Such study was suspended for many years but has then been started again during recent decades. New research into bioelectricity is creating alternatives in the health field; one of them is an electrodermal response associated with the wound healing, cell stimulation and psychopathology diagnostic. This article presents some of the first responses and models concerning electrodermal activity. Theoretical, clinical and review papers were studied and classified to show the amplitude and variety of bioelectrical responses. Electrodermal activity is only one of many applications having an abundant amount of evidence regarding diagnosis and treatment starting from bioelectrical signals. Electrical tissue response requires more experimental, theoretical and clinical research in many fields involving an organism’s behaviour to ascertain, propose and create new treatment alternatives for different pathologies.
... It has been shown that an intensity of about 35% is the most efficient in aiding recovery from repeated exercise bouts, all-out and competition events (Dodd et al. 1984;Hermansen & Vaage 1977;Belcastro & Bonen 1975), and athletes generally perform a running exercise at submaximal intensity or a reduced exercise intensity to enhance recovery from EIMD (Cheung et al. 2003;Hough 1902). It has been reported that local blood flow increases during and after exercise (Sergueef et al. 2004;Robergs et al. 1997), and it may be that the increased blood flow to a damaged area may help to remove cellular debris, increase nutrient delivery, and enhance tissue repair (Sayers et al. 2000;Robergs et al. 1997;Mohr et al. 1987). It seems that low-intensity exercise may be beneficial for the recovery of both muscle damage and RE from EIMD. ...
... No significant differences (p > 0.05) between the groups were found. concentric exercise (Sergueef et al. 2004;Robergs et al. 1997;Mohr et al. 1987). Blood flow is an important factor in reducing pain, facilitating the healing of damaged muscle, reducing swelling (Mohr et al. 1987), and enhancing the efficiency of muscle contraction (Clemente et al. 1991). ...
... concentric exercise (Sergueef et al. 2004;Robergs et al. 1997;Mohr et al. 1987). Blood flow is an important factor in reducing pain, facilitating the healing of damaged muscle, reducing swelling (Mohr et al. 1987), and enhancing the efficiency of muscle contraction (Clemente et al. 1991). However, this contention may not explain our results. ...
This study examined whether a short period of either low-intensity running (LIR) exercise or passive rest following downhill running (DHR) would enhance the recovery of muscle damage and running economy (RE). Twenty-four active males participated in the study, and were randomly assigned into LIR (n = 12) and control (CON; n = 12) groups. Both groups performed one bout of DHR for 30 minutes on a treadmill with an incline of −26% and at the intensity of 70% of peak oxygen consumption (V · O 2peak). The LIR group per-formed a 30-minute bout of running at a 0% incline and an intensity of 35% of V · O 2peak , 30 minutes after the DHR. The 30-minute bout of LIR was repeated each day for 4 days by the LIR group, while the CON group passively rested during the same time period. RE was measured by rate of V · O 2 , minute ventilation, respiratory exchange ratio, heart rate, rating of perceived exertion, and stride frequency during a 5-minute bout of level running at 85%of V · O 2peak performed before DHR, and at 2, 5 and 7 days thereafter. Blood lactate concentra-tion was measured before and at 3 minutes after a 5-minute bout of level running (performed before DHR, and at 2, 5 and 7 days thereafter). Maximal isometric voluntary strength of the knee extensor, vertical jump, the level of muscle soreness, plasma creatine kinase activity, and myoglobin concentration were assessed before, immediately after, and every day for 7 days after DHR. All criterion measures were significantly changed (p < 0.05) following the DHR for both groups. In addition, the recovery of all criterion measures for the LIR group after DHR was not significantly different (p > 0.05) from that of the CON group. These results suggest that a 30-minute bout of LIR every day for 4 days following DHR did not improve the recovery of muscle damage or alter RE.
... First, effect of muscle pumping brought about ES applied above the motor threshold. Several previous papers [17][18][19][20] reported that stimulated muscle contraction was accompanied with increase in arterial flow and venous return in healthy subjects or animal models. Second, sympathetic inhibition resulted in the sympathetic reflex by afferent type III and IV fibers were demonstrated in the animal models. ...
... Second, sympathetic inhibition resulted in the sympathetic reflex by afferent type III and IV fibers were demonstrated in the animal models. 17,18 Third, Kaada and colleagues 14,21,22 established that the release of vasodilator substances such as cholinergic, histaminergic, and dopaminergic and of vasoactive intestinal polypeptides, prostaglandins, and plasma kinins dilated skin vessels during ES. These mechanisms might also play a role in our study. ...
Objectives:
We investigated the effects of electrical stimulation therapy on cutaneous and muscle blood flow in critical limb ischemia patients following regenerative therapy.
Methods:
Three groups were studied: 10 healthy young subjects, 10 elderly subjects, and 7 critical limb ischemia patients after regenerative therapy. After 5 min rest, electrical stimulation was applied at 5 Hz on the tibialis anterior muscle for 10 min. We estimated the relative changes in oxyhemoglobin and total hemoglobin compared to the basal values at rest (Δ[HbO2], Δ[Hbtot]), which reflected the blood flow in the skin and muscle layer, and we simultaneously measured the tissue O2 saturation (StO2) throughout the electrical stimulation and recovery phase by near-infrared spectroscopy.
Results:
The Δ[HbO2] and Δ[Hbtot] values of the muscle layer in critical limb ischemia patients increased gradually and remained significantly higher at the 5-min and 10-min recovery periods after the electrical stimulation without reducing the StO2, but there is no significant change in the other two groups. Skin blood flow was not influenced by electrical stimulation in three groups.
Conclusion:
This improvement of the peripheral circulation by electrical stimulation would be beneficial as the adjunctive therapy after regenerative cell therapy.
... Processes of bone elongation depend on the delivery of nutrients and hormones from the bloodstream (17,63,94). High temperature, exercise, and stimulated muscle contractions increase blood supply to bone (38,43,56,59,63,64,77,91), while cold temperature and muscle disuse decrease bone perfusion (14,20,25,42,43,45,77,80,87). Increased or decreased blood supply can enhance (17-19, 68, 95) or restrict (16,46,89) bone elongation, respectively, suggesting that some of the growth effects common to activity and temperature could stem from changes in the vasculature. ...
... Mechanistically, one way to increase solute delivery to the growth plate would be to increase the total volume of blood arriving at a bone by increasing flow rate, enlarging vessel diameter (vasodilation), and/or increasing vessel numbers (angiogenesis). Our results complement published data that show that total bone blood flow is increased with exercise (43,56,59,63,64,91) and are especially relevant in light of the known correlation between increased blood flow and bone elongation (17-19, 68, 95). Our data are a key advancement, because we illustrate for the first time that these exercise effects can occur locally in growth plate cartilage. ...
Ambient temperature and physical activity modulate bone elongation in mammals, but mechanisms underlying this plasticity are a century-old enigma. Longitudinal bone growth occurs in cartilaginous plates, which receive nutritional support via delivery of solutes from the vasculature. We tested the hypothesis that chronic exercise and warm temperature promote bone lengthening by increasing solute delivery to the growth plate, measured in real time using in vivo multiphoton microscopy. We housed 68 weanling female mice at cold (16°C) or warm (25°C) temperatures and allowed some groups voluntary access to a running wheel. We show that exercise mitigates the stunting effect of cold temperature on limb elongation after 11 days of wheel running. All runners had significantly lengthened limbs, regardless of temperature, while nonrunning mice had shorter limbs that correlated with housing temperature. Tail length was impacted only by temperature, indicating that the exercise effect was localized to limb bones and was not a systemic endocrine reaction. In vivo multiphoton imaging of fluoresceinated tracers revealed enhanced solute delivery to tibial growth plates in wheel-running mice, measured under anesthesia at rest. There was a minimal effect of rearing temperature on solute delivery when measured at an intermediate room temperature (20°C), suggesting that a lasting increase in solute delivery is an important factor in exercise-mediated limb lengthening but may not play a role in temperature-mediated limb lengthening. These results are relevant to the study of skeletal evolution in mammals from varying environments and have the potential to fundamentally advance our understanding of bone elongation processes.
... In the past, fatigue recovery has mostly been passive rest, which is simple and least restrictive, but the recovery effect is less advantageous compared to another active rest. For example, previous studies have found that performing mild centripetal contractions in the presence of muscle injury can increase blood flow fivefold, accelerate oxygen delivery to damaged muscles (Robergs et al. 1997), and accelerate the elimination of tissue fluid accumulation in swollen muscles (Mohr, Akers and Wessman, 1987), thus enhancing recovery efficiency (Clemente et al. 1991), but the effect of active recovery may vary depending on the approach and lasting time (Zhang, Wang and Ye, 2014), so the results are inconclusive. ...
The aim of this study is to study the effects and differences of different recovery methods such as passive break (PB), active break (AB), and vibration break (VB) on muscle performance recovery after muscle fatigue. The biceps brachii (BBM), which is prone to fatigue during exercise, was taken as the object to study. 10 healthy males were recruited to conduct the experiment. After the experiment, One-Way Repeated Measures ANOVA was used to compare the difference of muscle performance index (MVC, RMS, MF) between groups (PB, AB, VB) at different time points (pre-fatigue, post-fatigue, and post-recovery). JASA method was also used to analyze the muscle recovery effect. Results show 1-minute AB is more effective for muscle fatigue recovery between exercise sets than 1-minute VB after effects.
... The mechanisms behind the observed effects of HVMPC intervention may be explained by various studies that examined the effects of the current and the electrical properties of wounds. HVMPC was determined to enhance fibroblast proliferation (near cathode) [51][52][53] and keratinocyte proliferation [54], have antibacterial effects [55][56][57][58][59][60], increase collagen synthesis [51,61,62], and augment blood flow [63,64]. Another theory that may explain the results is the galvanotaxis theory (cell migration towards positive or negative electric charge). ...
This review was conducted to determine and quantify the efficacy of high-voltage monophasic pulsed current (HVMPC) in the treatment of stage II-IV pressure ulcers (PrUs), identify the details of HVMPC intervention parameters and the superior protocol, and ascertain other potential benefits and the safety of HVMPC intervention. Eleven studies, nine randomized controlled trials (RCTs) and two case series studies, matched the criteria and were included in the systematic review, whereas, only level 1 evidence RCTs were included in the meta-analysis. The percentage of wound surface area reduction per week was 12.39%; 95% CI, [10.43-14.37] for HVMPC plus standard wound care (SWC) and 6.96%; 95% CI, [5.56-8.38] for SWC alone or SWC plus sham HVMPC. The net effect of HVMPC was 5.4% per week (an increase of 78% greater than SWC alone or SWC plus sham HVMPC). Level 1, 2 and 4 evidence studies have consistently indicated that HVMPC plus SWC were more effective than SWC alone or SWC plus sham HVMPC in treating stage II-IV PrUs. Level 1 evidence studies showed that HVMPC intervention improved the healing of PrUs (reduced wound surface area), and combined with SWC, increased the probability of complete healing and almost eliminated the probability of worsening of healing. HVMPC intervention was shown to be relatively safe, with rare adverse reactions.
... 35,37 The evoked mechanisms involved in this regenerative effect are essentially increases in endoneural blood flow and growth factor synthesis, required for nerve sprouting. 36 ENS increases local blood flow velocity without promoting angiogenesis, 40 improves edema, and accelerates tissue repair. 41 Neuron response after injury puts the nerve cell in a regenerative state by inducing nerve regeneration via expression of neurotrophins and the regeneration-related genes 13,42,43 ; ENS seems to promote this mechanism. ...
Objective:
Immediate microsurgical nerve suture remains the gold standard after peripheral nerve injuries. However, functional recovery is delayed, and it is satisfactory in only 2/3 of cases. Peripheral electrical nerve stimulation proximal to the lesion enhances nerve regeneration and muscle reinnervation. This study aims to evaluate the effects of the motor cortex electrical stimulation on peripheral nerve regeneration after injury.
Methods:
80 rats underwent right sciatic nerve section, followed by immediate microsurgical epineural sutures. Rats were divided into 4 groups: Group 1 (control, n = 20): no electrical stimulation; group 2 (n = 20): immediate stimulation of the sciatic nerve just proximal to the lesion; Group 3 (n = 20): motor cortex stimulation (MCS) for 15 minutes after nerve section and suture (MCSa); group 4 (n = 20): MCS performed over the course of two weeks after nerve suture (MCSc). Assessment included electrophysiology and motor functional score at day 0 (baseline value before nerve section), and at weeks 4, 8, and 12. Rats were euthanized for histological study at week 12.
Results:
Our results showed that MCS enhances functional recovery, nerve regeneration and muscle reinnervation starting week 4 compared to the control group (p <0.05). The MCS even induces higher reinnervation rates compared to peripheral stimulation, with better results in MCSa group (p <0.05), especially in terms of functional recovery.
Conclusion:
MCS seems to have a beneficial effect after peripheral nerve injury and repair in terms of nerve regeneration and muscle reinnervation, especially when acute mode is used.
... Muscle fatigue sourced from continuous muscle contraction will lower late exercise performance and bring muscle injury response, and therefore, if effective recovery method is used within limited time, it will be quite beneficial to re-performance improvement and exercise injury reduction. Among them, muscle swelling is an important index to measure the effect of muscle recovery.In previous research; it is found that if mild concentric contraction is implemented under muscle injury, elimination of interstitial fluid accumulation within tumid muscle will be quickened [1], thus improving recovery efficiency [2]. Vibration training rising recently belongs to passive recovery method that can generate effect similar with active recovery without active muscle contraction, and this characteristics are quite helpful to fatigue recovery. ...
... The literature shows that HVPC did not promote angiogenesis in the neural tissue 26 , and in this study, we could see the same results. However, HVPC increased the blood flow speed 27 and increased microcirculation in the skin wounds 28 . Furthermore, increased capillary numbers were observed on day 14 after applying rectangular, biphasic, symmetric, and pulsed electrical currents to tenotomized and sutured Achilles tendons in rats 23 . ...
Objective:
To verify the efficacy of high voltage pulsed current in collagen realignment and synthesis and in angiogenesis after the partial rupturing of the Achilles tendon in rats.
Method:
Forty male Wistar rats were randomized into four groups of 10 animals each: sham, cathodic stimulation, anodic stimulation, and alternating stimulation. Their Achilles tendons were submitted to direct trauma by a free-falling metal bar. Then, the treatment was administered for six consecutive days after the injury. In the simulation group, the electrodes were positioned on the animal, but the device remained off for 30 minutes. The other groups used a frequency of 120 pps, sensory threshold, and the corresponding polarity. On the seventh day, the tendons were removed and sent for histological slide preparation for birefringence and Picrosirius Red analysis and for blood vessel quantification.
Results:
No significant difference was observed among the groups regarding collagen realignment (types I or III collagen) or quantity of blood vessels.
Conclusion:
High voltage pulsed current for six consecutive days was not effective in collagen realignment, synthesis, or angiogenesis after the partial rupturing of the Achilles tendon in rats.
... Cells within the wound electric field respond with a variety of biological and functional responses [5]. An externally applied electric field can then result in an electric current being driven along the wound surface, enhancing the endogenous electric field and arguably augmenting the healing processes [5,6,7,8,9,10,11,12]. Electric fields have been reported to direct cell migration in many different cell types [11,13,14], activate signaling pathways such as cdc42p, Rho/Rac, PI3K/PTEN and phosphatidylinositol (PIP) [11,15,16,17], activation of epithelial sodium channels [18], cellular electrotaxis of macrophages [19,20], neutrophils [19,21] and fibroblasts [22,23,24,25], increase production of ATP and DNA [19,26,27,28], increase collagen secretion by fibroblasts [22,29] and increase blood flow and capillary density [30,31,32]. Although there are some outcome-based and mechanistic evidence supporting electrical stimulation (ES) promoting wound healing [11], a better understanding is lacking because of limitation in standardized procedure of application of ES to wounds. ...
... Because of a relative low frequency of the bursts, the vasodilatation is expected as a primary effect of the micro-pulse stimulation on the blood vessels [12]. But the vasoconstriction as an effect of the used high voltage cannot be left out of consideration [13]. The burst width is another factor associated with the strength of the stimulus. ...
Reasons for performing study: Electrotherapy is used in human medicine and successively also in veterinary practice, but relatively little is known about the mechanisms of action in detail.This study is focused on identifying the physiological effects of micro-pulse stimulation, a new method designed for equine electrotherapy, using the thermodynamic sensing. Objectives: To establish on the basis of measurement with the Thermo Dynamic Sensors, if the micro-pulse stimulation has any effect on blood circulation. Methods: Twenty horses participated in this study. Two miniature Thermo Dynamic Sensors (TDS), working on the principle of the balance energy equilibrium and special designed for the measurement on horses, were placed on both forelimbs and monitored the changes in thermal activity. Micro-pulse stimulation of specified parameters was applied for a defined time only on one limb and the other was just considered as a reference. The measured responses were statistically processed, compared and evaluated. Results: The measured data were processed by basic and multivariate statistical analysis (correlation, Wilcoxon test, multidimensional scaling, and cluster analysis) which identified a significant difference between signals from stimulated and reference limb. A considerable increase of thermal activity is evident in signals from stimulated limb during the applied micro-pulse stimulation. Conclusions: Based on the results, it seems the micro-pulse stimulation really has physiological effect consisting in an increased blood perfusion which is associated with the warming-up of the stimulated area and this is detectable by the thermodynamic sensor. Potential relevance: Comparison and statistical evaluation of the measured signals provided a more detailed view on the thermal changes within the stimulated area, which is significantly related to blood circulation in limbs, and also with the support of the reduction of edema which could be one of the practical applications of micro-pulse stimulation (also tested parallel to this study).
... 14 Few studies have described the circulatory effects of HVES. In an experimental study, Mohr et al 15 found an increase in blood flow in the paws of rats following stimulation. According to Bélanger, 14 HVES increases blood flow in muscles due to the induction of contractions and offers the benefit of being more comfortable than other excitatory motor currents. ...
Objective:
The purpose of this study was to assess the effects of high-voltage electrical stimulation (HVES), continuous short wave diathermy, and physical exercise on arterial blood flow in the lower limbs of diabetic women with peripheral arterial disease.
Methods:
A crossover study was carried out involving 15 diabetic women (mean age of 77.87 ± 6.20 years) with a diagnosis of peripheral arterial disease. One session of each therapeutic resource was held, with a 7-day washout period between protocols. Blood flow velocity was evaluated before each session and 0, 20, 40 and 60 minutes after the administration of each protocol. Two-way repeated-measures analysis of variance with Bonferroni post hoc test was used for the intragroup and intergroup comparisons.
Results:
In the intragroup analysis, a significant reduction (P < .05) was found in blood flow velocity in the femoral and popliteal arteries over time with HVES and physical exercise and in the posterior tibial artery with the physical exercise protocol. However, no significant differences were found in the intergroup analysis (P > .05).
Conclusion:
Proximal blood circulation in the lower limb of diabetic women with peripheral arterial disease was increased by a single session of HVES and physical exercise, whereas distal circulation was only increased with physical exercise.
... Blood flow was then monitored continuously: a) 60 min prior to an electrically-evoked leg-kicking exercise (60 V, 100 pps, for 3 min for a total of 180 contractions), b) during the leg kicking exercise, and c) 90 min following exercise. This exercise bout was chosen per previous literature demonstrating that this protocol elicited an increase in femoral blood flow velocity in rats [12]. ...
Introduction
Extracellular adenosine triphosphate (ATP) stimulates vasodilation by binding to endothelial ATP-selective P2Y2 receptors; a phenomenon, which is posited to be accelerated during exercise. Herein, we used a rat model to examine how different dosages of acute oral ATP administration affected the femoral blood flow response prior to, during, and after an exercise bout. In addition, we performed a single dose chronic administration pilot study in resistance trained athletes.
Methods
Animal study: Male Wistar rats were gavage-fed the body surface area, species adjusted human equivalent dose (HED) of either 100 mg (n=4), 400 mg (n=4), 1,000 mg (n=5) or 1,600 mg (n=5) of oral ATP as a disodium salt (Peak ATP(R), TSI, Missoula, MT). Rats that were not gavage-fed were used as controls (CTL, n=5). Blood flow was monitored continuously: a) 60 min prior to, b) during and c) 90 min following an electrically-evoked leg-kicking exercise. Human Study: In a pilot study, 12 college-aged resistance-trained subjects were given 400 mg of ATP (Peak ATP(R), TSI, Missoula, MT) daily for 12 weeks, and prior to an acute arm exercise bout at weeks 1, 4, 8, and 12. Ultrasonography-determined volumetric blood flow and vessel dilation in the brachial artery was measured at rest, at rest 30 minutes after supplementation, and then at 0, 3, and 6 minutes after the exercise.
Results
Animal Study: Rats fed 1,000 mg HED demonstrated significantly greater recovery blood flow (p < 0.01) and total blood flow AUC values (p < 0.05) compared to CTL rats. Specifically, blood flow was elevated in rats fed 1,000 mg HED versus CTL rats at 20 to 90 min post exercise when examining 10-min blood flow intervals (p < 0.05). When examining within-group differences relative to baseline values, rats fed the 1,000 mg and 1,600 mg HED exhibited the most robust increases in blood flow during exercise and into the recovery period. Human study: At weeks 1, 8, and 12, ATP supplementation significantly increased blood flow, along with significant elevations in brachial dilation.
Conclusions
Oral ATP administration can increase post-exercise blood flow, and may be particularly effective during exercise recovery.
... Electrical stimulation (ES) activates the production of ATP and DNA, 4,11 makes fibroblasts generate more collagen, 7,12,13 and increases blood flow and capillary density. [14][15][16] ...
Significance: A range of studies point to the efficacy of electrical stimulation (ES) in wound treatment, but the methodology of its application has not been determined to date. This article provides a critical review of the results of clinical trials published by researchers using high-voltage pulsed current (HVPC) to treat chronic wounds. In describing the methodology of the trials, the article gives special attention to electric stimulus parameters, the frequency of procedures and total treatment duration. Recent Advances: HVPC is a monophasic pulsed electric current that consists of double-peaked impulses (5-200 μs), at very high peak-current amplitude (2-2.5 A), and high voltage (up to 500 V), at a frequency of 1-125 pulses per second. HVPC can activate "skin battery" and cellular galvanotaxis, and improves blood flow and capillary density. Critical Issues: HVPC efficacy was evaluated in conservatively treated patients with diabetic foot, venous leg and pressure ulcers (PUs), and in some patients with surgically treated venous insufficiency. Future Directions: The efficacy of HVPC as one of several biophysical energies promoting venous leg ulcer (VLU) and PU healing has been confirmed. Additional studies are needed to investigate its effect on the healing of other types of soft tissue defects. Other areas that require more research include the identification of the therapeutic effect of HVPC on infected wounds, the determination of the efficacy of cathodal versus anodal stimulation, and the minimal daily/weekly duration of HVPC required to ensure optimal promotion of wound healing.
... Cells within the wound electric field respond with a variety of biological and functional responses [5]. An externally applied electric field can then result in an electric current being driven along the wound surface, enhancing the endogenous electric field and arguably augmenting the healing processes [5,6,7,8,9,10,11,12]. Electric fields have been reported to direct cell migration in many different cell types [11,13,14], activate signaling pathways such as cdc42p, Rho/Rac, PI3K/PTEN and phosphatidylinositol (PIP) [11,15,16,17], activation of epithelial sodium channels [18], cellular electrotaxis of macrophages [19,20], neutrophils [19,21] and fibroblasts [22,23,24,25], increase production of ATP and DNA [19,26,27,28], increase collagen secretion by fibroblasts [22,29] and increase blood flow and capillary density [30,31,32]. Although there are some outcome-based and mechanistic evidence supporting electrical stimulation (ES) promoting wound healing [11], a better understanding is lacking because of limitation in standardized procedure of application of ES to wounds. ...
Exogenous application of an electric field can direct cell migration and improve wound healing; however clinical application of the therapy remains elusive due to lack of a suitable device and hence, limitations in understanding the molecular mechanisms. Here we report on a novel FDA approved redox-active Ag/Zn bioelectric dressing (BED) which generates electric fields. To develop a mechanistic understanding of how the BED may potentially influence wound re-epithelialization, we direct emphasis on understanding the influence of BED on human keratinocyte cell migration. Mapping of the electrical field generated by BED led to the observation that BED increases keratinocyte migration by three mechanisms: (i) generating hydrogen peroxide, known to be a potent driver of redox signaling, (ii) phosphorylation of redox-sensitive IGF1R directly implicated in cell migration, and (iii) reduction of protein thiols and increase in integrinαv expression, both of which are known to be drivers of cell migration. BED also increased keratinocyte mitochondrial membrane potential consistent with its ability to fuel an energy demanding migration process. Electric fields generated by a Ag/Zn BED can cross-talk with keratinocytes via redox-dependent processes improving keratinocyte migration, a critical event in wound re-epithelialization.
... Wykazano także, że stymulacja elektryczna zwiększa syntezę ATP i DNA w komórkach, a wskutek stymulacji elektrycznej fibroblastów następuje zwiększenie syntezy kolagenu [6, 9,131415. W stymulowanym elektrycznie obszarze może zwiększać się także przepływ krwi i gęstość kapilar161718. Wśród różnych zabiegów elektrycznych stosowanych w leczeniu uszkodzonych tkanek szczególną rolę odgrywa elektrostymulacja wysokonapięciowa (EWN). ...
... An increase in blood flow could therefore be a mechanism for the enhanced recovery of muscle force when light exercise is performed during recovery, but only when following a short period of immobilisation. Increased blood flow has also been established as an important factor in reducing pain, improving the healing of damaged muscle, reducing swelling and improving circulation (Mohr et al., 1987), as well as improving the efficiency of muscle contraction (Clemente et al., 1991). ...
ENGLISH ABSTRACT: Muscle injuries are associated with changes in skeletal muscle as well as the immune system. All studies investigating possible treatment modalities have found both positive and negative effects on muscle recovery. Since no universally accepted treatment modality exists, this thesis aims to determine whether a plant-derived antioxidant, proanthocyanidolic oligomer (PCO), might prove beneficial as treatment for sports injuries in order for athletes to return to the sports field quicker. The difference in recovery of muscle following both chronic (supplementation started 14 days prior to injury and continued thereafter) and acute supplementation (supplementation started two hours after injury) were also investigated. Both chronic and acute PCO supplementation in a rat hindlimb contusion injury model resulted in earlier muscle recovery, verified by an earlier satellite cell response compared to the placebo group. This effect was most prominent already at the four hour time point following injury, compared to day seven and three after chronic and acute placebo treatment respectively. PCO supplementation also resulted in quicker foetal myosin heavy chain (MHCf) expression compared to placebo treatment. Chronic supplementation specifically resulted in a blunted circulatory pro-inflammatory cytokine response, whilst allowing for a significant increase in IL-10, an anti-inflammatory cytokine, on day three (in the PCO group only). At tissue level, the response of the muscle pro-inflammatory cytokines, TNF- and IL- 6, coincided with the satellite cell response. Macrophage infiltration into the injured muscle also followed a similar pattern to that seen for the pro-inflammatory cytokines. Macrophages invaded the injured area quicker when supplemented with PCO chronically, however, macrophage infiltration could not explain the cytokine response seen with acute supplementation. Both chronic and acute supplementation with PCO was responsible for a severely blunted neutrophil response, a novel finding of this particular antioxidant. The main findings of the in vivo rodent study were that PCO was able to blunt the neutrophil response, whilst allowing for earlier macrophage infiltration. To establish possible mechanisms by which PCO might exert these beneficial effects, further analysis included determining macrophage phenotypes and neutrophil numbers in circulation. An in vitro neutrophil migration assay was also employed to further elucidate PCO’s ability to blunt neutrophil infiltration into the injured area. For this study, conditioned plasma were harvested from experimental animals and added together with neutrophils from control rats and granulocyte colony stimulating factor (G-CSF) to the insert of the migration chamber. A chemotactic factor, N-formyl methionine-leucine-phenylalanine (fMLP), was added to the bottom well and neutrophils were allowed to migrate for two hours. Results from this study indicated that neutrophil migration was attenuated in vitro in the presence of conditioned plasma from PCO supplemented rats only. The studies in this thesis on the effect of PCO on parameters of muscle and the immune system led to the following main conclusions: a) PCO supplementation resulted in earlier muscle recovery as a result of earlier satellite cell activation and MHCf synthesis; b) PCO favours an anti-inflammatory cytokine reaction, whilst blunting the pro-inflammatory cytokine response; and c) PCO blunted the neutrophil response whilst facilitating earlier macrophage infiltration into the injured area. The specific mechanism of action of PCO to blunt the neutrophil response specifically, possibly includes the ability to suppress adhesion molecule expression on the neutrophils themselves. However, this warrants further investigation. AFRIKAANSE OPSOMMING: Spier beserings word geassosiëer met veranderinge in skeletspier sowel as die immuunstelsel. Meeste studies wat moontlike behandelingsopsies ondersoek, het beide positiewe en negatiewe spierherstel gerapporteer. Omrede daar geen universele behandelingsmoontlikheid bestaan nie, is die doel van hierdie tesis om die effek van ‘n plantgebaseerde anti-oksidant, pro-antosianiedoliese oligomeer (PSO), as ‘n voordelige behandelingstrategie vir sportbeserings te toets. Die verskil in spierherstel na beide kroniese (supplementering wat 14 dae voor besering begin is, en volgehou is daarna) en akute supplementering (supplementering het twee uur na besering begin), is ook ondersoek. Beide kroniese en akute PSO supplementering, in ‘n rot agterbeen-kneusbeseringmodel, het gelei tot vroeë spierherstel. Die bevindinge is geverifiëer deur ‘n vroeë satelietselrespons in vergelyking met die plasebo groep. Hierdie effek was reeds opvallend vier uur na besering, in vergelyking met die dag sewe en dag drie tydpunt tydens kroniese en acute plasebo behandeling onderskeidelik. In vergelyking met die kontrole groep, het PSO supplementering ook gelei to vininger uitdrukking van miosienswaarketting (MHCf). Kroniese supplementering het spesifiek gelei to ‘n onderdrukte sirkulatoriese pro-inflammatoriese sitokien response, terwyl ‘n betekenisvolle toename in IL-10 op dag drie (in die PSO groep alleenlik) waargeneem is. Op weefselvlak, het die pro-inflammatoriese sitokiene, IL-6 en TNF- , dieselfde patron gevolg as die van satelietselle. Makrofaaginfiltrasie binne die beseerde spier het ook ‘n soorgelyke patroon gevolg. Makrofage het die beseerde area vinniger geïnfiltreer in die kronies PSO-gesupplementeerde groep, maar kon nie die sitokienrespons, wat waargeneem is met akute supplementasie, verklaar nie. Beide kroniese en akute PSO supplementering was verantwoordelik vir ‘n onderdrukte neutrofiel respons, wat ‘n nuwe bevinding is vir hierdie spesifieke anti-oksidant. Die hoof bevindinge in die in vivo rotstudies, is dat PSO instaat is om die neutrofielrespons te onderdruk, en sodoende vroeë makrofaaginfiltrasie teweeg te bring. Om meganismes waarby PSO hierdie voordelige effekte veroorsaak te ondersoek, is verdere analises gedoen om makrofaagfenotipe en neutrofielgetalle in die sirkulasie te bepaal. ‘n In vitro neutrofielmigrasie studie is ook aangewend om PSO se vermoë om neutrofielinfiltrasie in die beseerde area te onderdruk, te ondersoek. Neutrofiele van kontrole rotte, tesame met gekondisioneerde plasma van eksperimentele diere en granulosiet-kolonie stimulerende faktor (G-KSF), is toegelaat om vir twee ure in die teenwoordigheid van ‘n chemotaktiese faktor, N-formiel metionien-leusien-fenielalanien (fMLP) te migreer. Resultate van hierdie studie het aangetoon dat neutrofielmigrasie, in vitro, alleenlik onderdruk word in die teenwoordigheid van gekondisioneerde plasma van PSO-gesupplementeerde rotte. Die studies in hierdie tesis oor die effek van PSO op parameters van spier en die immuunsisteem, het tot die volgende hoofgevolgtrekkings gelei: a) PSO supplementering het vroeë spierherstel, as gevolge van vroeë satelietselaktivering en MHCf sintese, teweeg gebring; b) PSO verkies ‘n anti-inflammatoriese sitokien reaksie, terwyl dit die proinflammatoriese sitokienrespons onderdruk; en c) PSO onderdruk die neutrofielrespons, terwyl vroeë makrofaaginfiltrasie in die beseerde area gefasiliteer word. Die spesifieke meganisme van aksie van PSO, om die neutrofielrespons te onderdruk, kan moontlik die vermoë van neutrofiele om adhesie molekule uit te druk, insluit. Hierdie aanname moet egter verder ondersoek word. Thesis (PhD (Physiological Sciences))--University of Stellenbosch, 2011. Includes bibliography.
... Previous studies showed that muscle blood flow increased up to five-fold during concentric exercise (Robergs et al. 1997). Blood flow is an important factor in reducing pain, facilitating the healing of damaged muscle, and reducing swelling (Mohr et al. 1987), as well as enhancing the efficiency of muscle contraction (Clemente et al. 1991). This would explain the enhanced recovery of strength shown for the AM group in the present study (Figure 1), although soreness and swelling was not affected by exercise (Figures 3 and 4). ...
... 1,2 In experimental animals and humans with no known pathology, TENS has been shown to increase regional blood flow; however, the preponderance of evidence indicates that it does so only at stimulation intensities sufficient to cause skeletal muscle contraction. [3][4][5][6][7][8][9][10] Whether the increased blood flow found in these previous studies resulted from the TENS or from the skeletal muscle contraction produced by the TENS is unknown. It is also unclear whether electrically evoked muscle contractions offer a therapeutic advantage over voluntary contractions in terms of their ability to effect circulatory changes in the clinical setting. ...
Transcutaneous electrical nerve stimulation (TENS) increases regional blood flow when applied at intensities sufficient to cause skeletal muscle contraction. It is not known whether increases in blood flow elicited by TENS differ from those caused by voluntary muscle contraction. The purpose of this study, therefore, was to compare the hemodynamic effects of these 2 types of muscle contraction.
Fourteen people with no known pathology, aged 18 to 49 years (mean=28, SD=8), served as subjects. Calf blood flow (venous occlusion plethysmography), heart rate (electrocardiogram), blood pressure (automated sphygmomanometry), and force (footplate transducer) were measured during electrically induced and voluntary contractions.
Both modes of exercise caused rapid, but short-lived vasodilation (calf vascular resistance [mean(SEM]: (53%(3% for voluntary contractions versus (57%(4% for electrically induced contractions). The vasodilation caused by electrically induced contractions persisted for at least 15 seconds in the postexercise period, whereas the vasodilation elicited by voluntary contractions had resolved by this time point.
The hemodynamic changes elicited by voluntary and electrically induced muscle contractions are similar in magnitude but different in duration.
Lesions of the peripheral nervous system are, probably, one of the first places in terms of prevalence among human diseases, accompanied by temporary and permanent disability [2, 18]. In the structure of diseases of the peripheral nervous system, various forms of secondary muscular disorders are obligatory and often leading, which, causing locomotor disorders, lead to significant disability of patients. Deprived of full neurotrophic control, muscle undergoes atrophic and degenerative changes that significantly reduce the chances of restoration of its functional properties even with good reinnervation, carried out naturally or through neurosurgical reconstruction [7, 16, 25, 30]. In this regard, the development and in-depth study of such methods of therapy that would slow down denervation changes in the muscle are of great importance. Undoubtedly, one of the most effective methods in this regard is therapeutic electrical stimulation of the neuromuscular apparatus [4, 8, 11, 13, 16, 21].
Background:
Although numerous studies suggest the benefit of electrical stimulation (E-Stim) therapy to accelerate wound healing, the underlying mechanism of action is still debated. In this pilot study, we examined the potential effectiveness of lower-extremity E-Stim therapy to improve tissue perfusion in patients with diabetic foot ulcers.
Methods:
Thirty-eight patients with diabetic foot ulcers underwent 60 min of active E-Stim therapy on acupuncture points above the level of the ankle joint using a bioelectric stimulation technology platform. Perfusion changes in response to E-Stim were assessed by measuring skin perfusion pressure (SPP) at baseline and during 30 and 60 min of therapy; retention was assessed 10 min after therapy. Tissue oxygen saturation (SatO2) was measured using a noninvasive near-infrared camera.
Results:
Skin perfusion pressure increased in response to E-Stim therapy (P = .02), with maximum improvement observed at 60 min (11%; P = .007) compared with baseline; SPP reduced 10 min after therapy but remained higher than baseline (9%; P = .1). Magnitude of improvement at 60 min was negatively correlated with baseline SPP values (r = -0.45; P = .01), suggesting that those with lower perfusion could benefit more from E-Stim therapy. Similar trends were observed for SatO2, with statistically significant improvement for a subsample (n = 16) with moderate-to-severe peripheral artery disease.
Conclusions:
This study provides early results on the feasibility and effectiveness of E-Stim therapy to improve skin perfusion and SatO2. The magnitude of benefit is higher in those with poorer skin perfusion. Also, the effects of E-Stim could be washed out after stopping therapy, and regular daily application might be required for effective benefit in wound healing.
Background. The study aimed to assess the effectiveness of a therapeutic regimen combining kinesiotherapy, cryotherapy and electrical stimulation in patients with a surgically treated anterior cruciate ligament (ACL). Materials and methods. Twenty-four patients with reconstructed ACL participated in the study. The patients were randomly divided into Groups A and B, each group containing 12 individuals. Both groups received kinesiotherapy and cryotherapy according to the same programme, but Group B additionally received electrical stimulation. A therapeutic cycle comprised kinesiotherapy, cryotherapy and electrical stimulation procedures, ten of each kind. Sessions took place three times a week. The progress of healing in the patients was followed by assessing passive and active flexion at the knee, measuring the knee-joint circumference and load-testing of the limb. Results. After the treatment, both groups showed statistically significant improvements in flexion of the knee joint and reduced swelling of the joint. The leg-loading test performed after the treatment provided statistically significant improvement compared to pre-treatment data in both groups. No statistically significant differences were found between the two groups regarding treatment effectiveness. Conclusions. A combination of kinesiotherapy and cryotherapy is an effective adjunct to the treatment of patients with a surgically treated anterior cruciate ligament. The introduction of electrical stimulation did not offer additional therapeutic benefits.
Transcutaneous electrical nerve stimulation (TENS) is used to alleviate muscle pain, and there is some evidence it may affect healing in chronic wounds. An 80-year-old male patient with a chronic left lower extremity wound and a history of peripheral arterial disease, type 2 diabetes, hypertension, chronic obstructive pulmonary disease, and lung cancer presented for treatment. Previous protocols of care, mainly consisting of sharp debridement and daily dressing changes, had not resulted in a decrease in wound size. The patient had right and left iliac artery stenosis - not amenable to surgical intervention - and an ankle brachial index (ABI) of 0.63 on the left and 0.59 on the right lower extremities. On presentation, the wound measured 3.0 cm x 2.0 cm with a depth of 0.3 cm and a 0.5-cm tract at the 5 o'clock position. Treatment was changed to application of an ionic silver-containing Hydrofiber™ dressing and low-frequency TENS. Electrodes were applied 2 cm superior and inferior to the wound margin at a frequency of 2 Hz with a pulse width of 250 microseconds and amplitude of 33 mA. Treatment time was 45 minutes, twice daily, for 3 months, performed at home by the patient and his caregiver. After 4 weeks, wound dimensions decreased by 1.51% per day, and the wound was completely healed (100% epithelialized) after 12 weeks. At that time, the ABI of the left (treated) leg had increased to 0.71. Research is needed to determine the efficacy and effectiveness of low-frequency TENS to help clinicians provide evidenced-based treatment for wounds complicated by decreased blood flow.
Janssen TW, Hopman MT. Blood flow response to electrically induced twitch and tetanic lower-limb muscle contractions. Arch Phys Med Rehabil 2003;84:982–7.
High voltage stimulation (HVS) influences tissue repair at the level of the wound environment. This article discusses research findings and clinical use of HVS for enhancement of wound healing. A brief review of theories and current scientific rationale for use of HVS is provided. Included is a brief examination of research dealing with high voltage peak current, and wound healing processes. This article summarises recent developments and trends in the use of HVS for healing in order to facilitate clinicians' decision-making capabilities, and their understanding of treatment options.
The purpose of this study was to evaluate the effect of galvanic electrical stimulation on vascular perfusion in diabetic patients. Nineteen subjects with diabetes were enrolled. Eleven subjects (57.9%) were diagnosed with impaired peripheral perfusion based upon their initial transcutaneous oximetry values (< 40 mm Hg). The subjects were studied over a 2-day period. On the 1st day, one foot was electrically stimulated for four 60-minute periods by an external electrical stimulation device. Vascular perfusion of both feet was assessed before and after the sessions of electrical stimulation. On the 2nd day, no electrical stimulation was applied and noninvasive vascular measurements were repeated. For the 1st hour, transcutaneous oxygen pressure was measured continuously during stimulation at the lateral aspect of the leg. Subsequently, perfusion between the periods of stimulation was measured on the dorsum of the foot with both transcutaneous oximetry and laser Doppler flowmetry after each stimulation period. In the group with impaired peripheral perfusion, a significant rise in tissue oxygenation as compared to the control measurements was measured during the first 5 minutes of stimulation (p < .040). For those without vascular disease (TcpO2 > 40 mm Hg) however, there was not a significant increase compared to baseline (p = .280). After the periods of stimulation, the stimulated feet did not show any higher perfusion levels than the control feet. Patterns in perfusion during the day, as measured by laser Doppler flowmetry, were similar in the tested feet and in the controls. These data suggest that external subsensory electrical stimulation induces a transient rise in skin perfusion in persons with diabetes and impaired peripheral perfusion.
Pain is the main symptom of patients with temporomandibular disorder (TMD).
To evaluate the effect of cathodal high-voltage electrical stimulation (HVES) on pain intensity in women with TMD.
Twenty women with TMD (24.25 ± 8.90 years old) participated in the study. They were divided into experimental group (EG, n=10), which received 10 applications of HVES, and placebo group (PG, n=10), which received sham treatment with disconnected HVES equipment. For the sample selection, we used the Research Diagnostic Criteria for Temporomandibular Disorder (RDC/TMD). Pain level was evaluated using a visual analog scale (VAS) applied prior to and after the tenth application of HVES. Data were analyzed using the Wilcoxon signed-rank test and the Mann-Whitney test.
Ten applications of HVES reduced pain intensity in the EG (p=0.01). In the PG, there was no significant difference (p=0.20). After the application of HVES, no difference was found (p=0.65) between the groups.
The cathodal HVES was effective in reducing pain in women with TMD. Trial Registration RBR-4bk94x.
The use of electrical stimulation has been studied in a variety of wounds emphasizing different variables with regard to provision of therapy. The purpose of this prospective, randomized, controlled clinical study was to evaluate the effect of high-voltage electrical stimulation (HVES) on nonhealing, lower-extremity, Stage II and Stage III pressure ulcers. Patients admitted for care and eligible to participate in the study received standard supportive care and topical treatments covered with wet-to-moist dressings. Patients assigned to the treatment arm of the study also received HVES (100 V; 100 μs; 100 Hz) continuously for 50 minutes once daily, five times per week. Patients were followed until healing for a maximum of 6 weeks. Wound tracings and measurements were obtained weekly. Over a 4-year period, 26 patients were enrolled in the treatment and 24 in the control group. Ulcers had existed for an average of 3.17 and 2.83 months in the treatment and control groups, respectively. Most were classified as Stage II (17 in the treatment and 16 in the control group) with an average baseline size of 4.54 cm2 and 3.97 cm2, respectively. Wound areas and linear measurements decreased significantly in both groups (P <0.05), but increases in granulation tissue were significant in the treatment group only (P = 0.006). Wound area, linear measurement, wound volume, and granulation tissue changes were statistically significantly greater in the treatment than in the control group starting in the second week of treatment. Week 6 surface area change was 88.9% (SD 14) in the treatment and 44.4% (SD 63.1) in the control group (P = 0.00003). Correlation coefficients between changes in wound surface area, longest length, and longest width were R = 0.96 and R = 0.98 in the treatment and R = 0.94 and R = 0.89 in the control group. HVES improved the healing rate of recalcitrant Stage II and Stage III pressure ulcers. Research to compare the effectiveness of using cathodic and anodal stimulation combined or alone and to determine the optimal duration of these two types of electrical stimulation is warranted.
Edema is a normal response to injury. Even the smallest injury is associated with some inflammation, and initial edema is part of the normal inflammatory process. However, edema becomes a concern when it persists beyond the inflammatory phase. Once we have progressed into the rebuilding, or fibroplastic phase of healing, edema will delay healing and contribute to complications such as pain and stiffness. Early prevention and management to prevent this progression are therefore critical. This article discusses edema in relation to stages of healing and presents the research behind techniques available to the clinician to manage localized extracellular upper extremity edema in the patient with an intact lymphatic system.
Peripheral nerve injury causes prolonged functional limitation being a clinical challenge to identify resources that accelerates its recovery.
To investigate the effect of high-voltage electrical stimulation (HVES) on the morphometric and functional characteristics of the regenerated nerve after crush injury in rats.
Twenty Wistar rats were randomly allocated into 4 groups: Control (CON) - without injury and without HVES; Denervated (D) - sciatic nerve crush only; Denervated + HVES - sciatic nerve crush and HVES; SHAM - without injury but HVES. The HVES and SHAM groups were stimulated (100 Hz; minimum voltage of 100 V, 20 μs, 100 μs interpulse interval) for 30 min/day, 5 days/week. The sciatic functional index (SFI) was evaluated before the injury and at the 7th, 14th and 21st postoperatory (PO) days. Neural components and the area density of connective tissue, blood vessels and macrophages were analyzed.
Axonal diameter was higher on the HVES than on D group, reaching almost 80% above the control values after 21 days (p<0.05). Fiber diameter and myelin sheath thickness were higher on the HVES than on D group (p<0.05) reaching 96.5% and 100% of the control values, respectively. Functional recovery at the 14th PO day was better on group HVES. The macrophages and connective tissue area density was lower on the HVES group, while blood vessels number did not differ among groups.
The HVES accelerated the functional recovery, potentiated the nerve fibers maturation and decreased macrophages and connective tissue area density, suggesting acceleration of neural repair.
Electrical stimulation is often used to control edema formation after acute injury. However, it is unknown whether its theoretical benefits translate to benefits in clinical practice.
To systematically review the basic-science literature regarding the effects of high-voltage pulsed stimulation (HVPS) for edema control.
CINAHL (1982 to February 2010), PubMed (1966 to February 2010), Medline (1966 to February 2010), and SPORTDiscus (1980 to February 2010) databases were searched for relevant studies using the following keywords: edema, electrical stimulation, high-volt electrical stimulation, and combinations of these terms. Reference sections of relevant studies were hand-searched. Included studies investigated HVPS and its effect on acute edema formation and included outcome measures specific to edema. Eleven studies met the inclusion criteria. Methodological quality and level of evidence were assessed for each included study. Effect sizes were calculated for primary edema outcomes.
Studies were critiqued by electrical stimulation treatment parameters: mode of stimulation, polarity, frequency, duration of treatment, voltage, intensity, number of treatments, and overall time of treatments. The available evidence indicates that HVPS administered using negative polarity, pulse frequency of 120 pulses/s, and intensity of 90% visual motor contraction may be effective at curbing edema formation. In addition, the evidence suggests that treatment should be administered in either four 30-min treatment sessions (30-min treatment, 30-min rest cycle for 4 h) or a single, continuous180-min session to achieve the edema-suppressing effects.
These findings suggest that the basic-science literature provides a general list of treatment parameters that have been shown to successfully manage the formation of edema after acute injury in animal subjects. These treatment parameters may facilitate future research related to the effects of HVPS on edema formation in humans and guide practical clinical use.
The purpose of this study was to determine whether high voltage pulsed electrical stimulation reduces microvascular permeability to plasma proteins in a simulation of acute edema. Fourteen male golden hamsters were anesthetized and prepared for fluorescence microscopy of the cheek pouch. Intravenous fluorescein-labeled dextran (MW 150,000) served as a tracer of plasma proteins. Protein leaks from the microvessels were quantified every 5 minutes for a 25-minute baseline period and again after a 5-minute superfusion with 10(-5)-M histamine. High voltage stimulation (HVS) was applied simultaneously with the histamine to the vascular bed of the treatment animals in a dosage of 10, 30, or 50 V; the control animals received no electrical stimulation. Histamine increased microvessel leakiness in all groups, but the number of posthistamine microvessel leaks was significantly less in animals that received a 30- or 50-V dose of HVS than in the control animals or those that received a 10-V dose. The study results suggest that at intensities greater than a threshold dose, HVS reduces microvessel leakiness. Reduced microvessel leakiness may be one mechanism by which HVS retards edema formation.
The purpose of this study was to test the effect of high voltage stimulation (HVS) on edema reduction in the rat hindpaw. The animals were divided into a control group (n = 20) and a treated group (n = 20). The right hindpaw volume was measured, and then the animal's paw was traumatized. The animals in the treated group were treated with HVS at 24, 48, and 72 hours posttrauma. Paw volume measurements were made on all animals at 0, 24, 48, 72, and 96 hours posttrauma. In addition, the paw volume was measured in the treated group both before and after HVS. The results showed that animals in both groups had a significant decrease in paw volume over the experimental period, but no significant difference was found between the two groups in the amount of edema reduction. The HVS treatment did not produce a significant change in paw volume immediately after treatment.
Results from five independent studies from our laboratory indicate that cathodal high-voltage pulsed current (HVPC) significantly curbs posttraumatic edema formation in several animal models. Conversely, anodal HVPC did not curb edema formation. The mechanism by which HVPC reduces edema formation is unknown. We hypothesize that HVPC causes a decrease in local blood flow by active vasoconstriction of arterioles. Because we had previously observed positive effects with cathodal HVPC but not anodal HVPC, we further hypothesized that cathodal but not anodal HVPC would reduce diameters of histamine-dilated arterioles. Changes in diameters of resistance arterioles (5 to 30 microns internal diameter) were measured directly in cheek pouches of anesthetized hamsters, using in vivo video microscopy. Three minutes after superfusion with the inflammatory mediator (histamine) was begun, sensory-level HVPC at 120pps was applied concurrently for 30 minutes. Five animals received cathodal HVPC and five received anodal HVPC. Four other animals received 30-minute treatments of both cathodal and anodal HVPC in random order. Three control animals received histamine without HVPC for 30 minutes. Diameter changes of one arteriole from each cheek pouch was measured every 20 seconds throughout the treatment period. One-way analysis of variance (ANOVA) with repeated measures showed that diameters of histamine-dilated controls varied little over 30 minutes, and that adding cathodal HVPC did not significantly alter diameters of arterioles superfused with histamine. However, applying anodal HVPC to histamine-dilated arterioles significantly reduced arteriolar diameters. These results do not support the hypothesis that cathodal HVPC curbs edema formation by increasing arteriolar tone in the injured area.
The events that lead to tissue repair are very complex. Because our understanding of these processes is increasing in scope, the use of nontraditional treatment therapies should be considered. Evidence is reported in the literature that both electrical stimulation and ultrasound therapies may be beneficial in certain circumstances to heal various wound types. Owing to clinicians' unfamiliarity with the current research and general understanding of such therapies, many patients receive only traditional treatment and remain unexposed to the potential benefits of the nontraditional. With continued research to better define optimal treatment parameters, improved wound healing will result.
Electrotherapy is used clinically according to a variety of protocols and at various intensities with the intent of effecting any number of physiological changes. The purpose of this study was to determine if the increased degree of microvascular perfusion observed following 2,500 Hz transcutaneous neuromuscular electrical stimulation (TNMES) is dependent on evoked muscle contractions. The tibialis anterior (TA) and extensor digitorum longus (EDL) muscles from 30 male rats were analyzed. Six animals were untreated and served as controls, while the TA and EDL muscles of six animals were treated with TNMES at current intensities three times that needed to evoke a minimum visible contraction in the TA (M-TNMES). The remaining animals were treated with gallamine, which effectively blocked neurally mediated muscle contraction. The TA and EDL muscles of six gallamine-treated rats received no TNMES and served as shams (G-Sham), six received M-TNMES (GM-TNMES), and six received TNMES at intensities sufficient to produce sustained muscle contraction with a neuromuscular blockade in place (G-HIS). Perfused microvessels were labeled with fluorescein isothiocyanate-bovine serum albumin. The degree of microvascular perfusion was determined by calculating perfused microvessel/muscle fiber ratios (PV/F). The mean PV/F ratios of all groups were compared using Fisher's LSD (alpha = 0.05). When compared to controls, the PV/F ratios of the TA and EDL muscles in M-TNMES and G-HIS groups showed a significant (p < or = 0.05) increase while the G-Sham and GM-TNMES groups were similar to controls.(ABSTRACT TRUNCATED AT 250 WORDS)
Numerous human and animal efficacy studies have demonstrated that electrical stimulation of the correct charge, density and total energy causes dramatically improved healing of dermal wounds. The investigations of biological actions (in vitro, animal, and human) demonstrate several effects that go a long way to explaining why electrical stimulation works.
To discuss recent research and advances in electrical stimulation of wound healing.
Based on the latest scientific understanding of the wound healing process, one would expect a beneficial outcome from a therapy what decreases edema, debrides necrotic tissue, attracts neutrophils and macrophages, stimulates receptor sites for growth factors, stimulates growth of fibroblasts and granulation tissue, increases blood flow, stimulates neurite growth, induces epidermal cell migration, prevents post-ischemic oxygen radical-mediated damage, inhibits bacteria, and reduces numbers of mast cells.
Taken together, the efficacy studies and the "mechanism of action" studies provide compelling, scientific evidence that electrical stimulation is safe and effective for promoting the healing of dermal wounds.
To determine the effect of transcutaneous neuromuscular electrical stimulation (TNMES) on the degree of microvascular perfusion in autonomically denervated skeletal muscle.
A completely randomized experimental design was used to compare the effects of TNMES on the degree of microvascular perfusion in the tibialis anterior (TA) and extensor digitorum longus (EDL) muscles from autonomically denervated rats (Ch-TES) to the degree of microvascular perfusion in the same muscles of untreated controls, rats receiving only TNMES (TES), and rats receiving only autonomic denervation (shams).
All electrical stimulation treatments were delivered via carbon silicone surface electrodes, and evoked sustained tetanic contraction of the TA and EDL muscles. Autonomic denervation was achieved by the application of chlorisondamine.
The degree of microvascular perfusion was determined for the deep (DTA) and superficial (STA) region of the TA muscle and the EDL muscle by calculating their perfused microvessel/muscle fiber (PV/F) ratio.
The PV/F ratio in the DTA from Ch-TES animals was greater (p < or = .05) than that in the same muscle from control and sham animals. The PV/F ratios in the STA and EDL from Ch-TES animals were not significantly (p > .05) different from the PV/F ratio in the respective muscles of shams.
The response of the microvasculature in autonomically denervated skeletal muscle to TNMES that evokes muscle contraction is variable, and (2) mechanisms other than autonomic regulation may be involved in this hyperemic response.
To investigate the effect of unilateral cast immobilization with and without surface electrical stimulation (ES) on the tibialis anterior (TA) muscle of rabbits.
Prospective randomized trial.
University medical school.
53 New Zealand White rabbits (aged 54 to 63 days, weight 1.73 to 1.91 kg). METHODS AND INTERVENTION: Random assignment, for a 3-week period, to one of four groups: C group (control group), I group (immobilization group), S group (group of electrical stimulation which was stimulated isometrically at 50 Hz, 30 minutes per day, 5 times a week), and IS group (immobilization group which, like the S-group, received electrical stimulation).
Muscle wet wight, muscle fiber cross-sectional area, muscle fiber types, and muscle capillary supply.
Muscle wet weight decreased significantly in the I group by 19% (p < or = .05), with a corresponding significant reduction in the total muscle fiber cross-sectional area of 26% (p < or = .05). No significant changes were observed in muscle wet weight and muscle fiber cross-sectional area in the S and IS groups. Interstitial fibrosis was observed in the I group and occasionally in the IS group. No significant changes in the total number of muscle fiber types I and II were found in all experimental groups. The capillary supply of the S and IS groups did not change significantly. However, capillary-to-fiber ratio was significantly reduced by 20% with a simultaneously nonsignificant increase in capillary density (capillaries/mm2) of 11% (p > .05) in the I group. Furthermore, muscle fiber regeneration was observed predominantly in the I group.
In this experimental model, ES effectively prevented immobilization-induced muscle atrophy by minimizing reduction of muscle fiber cross-sectional area, interstitial fibrosis, and impaired blood supply.
Research into treatment techniques for tissue repair has undergone tremendous discus sion and growth in recent years. There are many treatment facets to consider when addressing the healing process. Treatment options may range in scale from global concerns to effects produced at a cellular level. Global tissue repair issues include health care coverage, reimbursement, and the in teraction of health care professionals on a wound care team. Client-centered matters may also affect healing. For example, health care professionals may choose to use a team approach including the client, family, and other care givers in the management of tissue healing. Other client-centered factors that af fect the healing process include injury, disease, nu trition, and compliance. Last, there are treatment components affecting the tissue or wound environ ment. Previous articles in this journal have covered many cellular aspects of tissue and wound environ ment issues with regard to tissue healing and re pair. Electrotherapy influences tissue repair at the level of the wound environment. This article dis cusses research findings and the clinical use of electrotherapy in tissue repair. A brief review of the theories and current scientific rationale for use of electrotherapy in tissue healing is provided. Included is a brief examination of research dealing with electrotherapy and tissue healing. Clinical treatment decisions-involving types of electrical current, polarity, electrode placement, and other pa rameters as well as precautions and contraindications -are discussed. This article summarizes recent de velopments and trends in the use of electrotherapy for tissue repair in order to facilitate clinicians' de cision-making capabilities and their understanding of treatment options.
The current study was designed to assess the putative physiological effects of H-wave therapy (HWT, a mode of therapeutic electro-stimulation) on skin blood flow in humans and to determine the relevance of frequency to any such effects. Laser Doppler flowmetry was used to record changes in blood perfusion on the dominant forearm of healthy human volunteers (n=36), who were each assigned, under randomized double blind conditions, to one of three experimental groups: placebo or HWT at 2 or 60 Hz. HWT stimulation was applied for 20 min, during which time concomitant skin temperature was recorded using three surface skin thermistors. Statistical analysis of perfusion measurement and skin temperature changes pre-, during and for up to 18 min post-HWT stimulation showed a highly significant increase in skin blood flow in the 2 Hz group when compared to placebo and 60 Hz (P<or/ = 0.01). This was associated with a significant increase in skin temperature during the period of stimulation (P<or/ = 0.05). No such differences were observed in the 60 Hz group. These results provide evidence that low-frequency HWT may produce direct localized effects on cutaneous blood flow, a finding relevant for clinicians working in the field of tissue repair.
The reported non-analgesic effects of transcutaneous electrical nerve stimulation (TENS) include alterations to the local circulation; however, research in this area has produced equivocal findings. In the present study, the effect of low- (4 Hz) and high-frequency (110 Hz) TENS on forearm skin blood perfusion was assessed using laser Doppler flowmetry. The effect on skin temperature was also assessed using a skin thermistor. Thirty healthy human volunteers were recruited and randomly assigned to a control or one of the two treatment groups. TENS was applied to the skin overlying the median nerve under double-blind conditions for 15 min. Blood flow and skin temperature readings were recorded pre-TENS, during TENS application and continued for 15 min post-TENS application. Analysis of results showed significant increases in blood perfusion during the treatment period in the low-frequency group when compared to the other two groups (P = 0.0106; ANOVA). No significant changes in skin temperature were observed. The results of this study demonstrate that low-frequency TENS produces a local increase in cutaneous blood flow.
The purpose of the present study was to determine whether activity would affect the recovery of muscle function after high-force eccentric exercise of the elbow flexors.
Twenty-six male volunteers were randomly assigned to one of three groups for a 4-d treatment period: immobilization (N = 9), control (N = 8), and light exercise (N = 9). Relaxed arm angle (RANG), flexed arm angle (FANG), maximal isometric force (MIF), and perceived muscle soreness (SOR) were obtained for 3 consecutive days pre-exercise (baseline), immediately post-exercise, and for 8 consecutive days after the 4-d treatment period (recovery). During the treatment period, the immobilization group had their arm placed in a cast and supported in a sling at 90 degrees. The control group had no restriction of their arm activity. The light exercise group performed a daily exercise regimen of 50 biceps curls with a 5-lb dumbbell.
All subjects showed a prolonged decrease in RANG, increase in FANG, loss in MIF, and increase in SOR in the days after eccentric exercise. During recovery, there was no significant interaction observed among groups over time in RANG (P > 0.05) or FANG (P > 0.05), but there was a significant interaction observed among groups over time in both MIF (P < 0.01) and SOR (P < 0.01). Recovery of MIF was facilitated by light exercise and immobilization, whereas recovery from SOR was facilitated by light exercise and delayed by immobilization.
The recovery of MIF in both the light exercise and immobilization groups suggests that more than one mechanism may be involved in the recovery of isometric force after eccentric exercise.
Development of techniques for the continuous measurement of regional blood flow and vascular resistance in intact small animals has been impeded primarily by the bulkiness of flow probes. The availability of an ultrasonic pulsed Doppler flowmeter system enabled us to construct miniaturized probes using 1-mm-diameter piezoelectric crystals that emit a 20-mHz signal and receive the reflected sound waves from passing blood cells. The finished flow probe is approximately 2.5-4 mm long and 2 mm in cross-sectional diameter with lumen diameters appropriate for the rat, ranging from 0.7 to 1.2 mm. This report describes the materials and methods involved in constructing and implanting the probes in rats to monitor renal, mesenteric, and hindquarter blood flow velocity. The accuracy of the pulsed Doppler method in detecting changes in regional blood flow and vascular resistance was established by the demonstration of a highly significant correlation between velocity recorded from the Doppler unit and volume flow recorded simultaneously. These data indicate that the ultrasonic pulsed Doppler flowmeter provides the opportunity to measure changes in regional blood flow and vascular resistance in a conscious freely moving rat.
In 13 anesthetized dogs with their vagi cut and their carotid sinuses kept at constant pressure, the gracilis artery, cranial tibial artery, and lateral saphenous vein of the left hind limb were isolated and perfused at constant flow. In the right hind limb, muscle afferents were stimulated by electrodes in the thigh muscles. At 5 Hz, aortic blood pressure decreased 45 ± 8 mm Hg; perfusion pressure decreased in the gracilis muscle and the paw (26 ± 6 mm Hg and 26 ± 5 mm Hg, respectively) and increased in the saphenous vein (13 ± 3 mm Hg). These effects were not prevented by paralysis of the stimulated muscles, beta-receptor blockade, or administration of atropine or antihistaminic drugs. At 40 Hz, aortic blood pressure increased 29 ± 8 mm Hg; perfusion pressure increased in the gracilis muscle and the paw (33 ± 5 mm Hg and 33 ± 3 mm Hg, respectively) and decreased in the saphenous vein (20 ± 2 mm Hg). These effects were prevented or reversed by paralysis of the stimulated muscles. Similar effects were obtained by central stimulation of the femoral nerve. Left sympathectomy or alpha-receptor blockade abolished the responses in the isolated vascular beds. Thus, muscle contraction is necessary only to activate the muscle afferents which cause constriction of resistance vessels in muscle and paw and dilation of cutaneous veins.
Electrical calf muscle stimulation during surgery has been used for the prevention of deep vein thrombosis (DVT) with varied results in several studies. This effect is mainly achieved by the reduction of venous stasis in the legs. Another possible beneficial effect might be an increased fibrinolytic activity of the blood secondary to the muscle contractions. Previously, single electrical impulses have been used for stimulation, giving rise to ‘single twitches’ in the muscles. In the present study the effect on calf volume of muscle stimulation with groups of impulses giving a short-lasting tetanus was investigated. Changes in calf volume were recorded by strain gauge plethysmography. Optimal values for duration, number and frequency of the impulses within the groups were determined. Stimulation with groups of impulses reduced calf venous volume approximately three times more efficiently than stimulation with single impulses. Calf muscle stimulation did not enhance the increase in fibrinolytic activity of venous blood observed after oesophago- or laryngoscopies under general anaesthesia.
Studies were designed to characterize the distribution of cardiac output during induced isometric exercise in anesthetized dogs. The response to isometric exercise involved significant increases in heart rate (+12 +/- 3%(SE)), mean arterial pressure (+13 +/- 2%), cardiac output (+26 +/- 8%), and respiratory minute volume (+75 +/- 26%); total peripheral resistance did not change significantly. Significant changes in blood flow were observed during isometric exercise in kidneys (-18 +/- 6%) and contracting limb muscles (+453 +/- 154%). Flow to liver (hepatic artery), spleen, brain, and myocardium remained near control values. Section of spinal dorsal roots L6-L7 abolished the responses to isometric exercise except for the increase in flow to exercising limb muscles. Alpha-adrenergic receptor blockade abolished the decrease in renal blood flow during isometric exercise; however, the increase in flow to exercising limb muscles was not affected by either alpha- or beta-adrenergic blockade.
Electric stimulation of the spinal cord and posterior roots has been carried out in 9 patients with varying degrees of vascular insufficiency in a limb. Many of these patients were failures in terms of the effect of sympathectomy and bypass procedures. Striking relief of pain occurs. Infarcted tissue is not restored, but healing is promoted. It is felt that these results are due to antidromic stimulation of C fibers in dorsal roots which provides changes in circulation beyond that obtained with regional sympathectomy and indeed in patients who have had sympathectomy. Percutaneous stimulation can be carried out initially as a trial before any surgical procedure is done.
Sixteen patients who had electrical stimulation applied to various portions of the nervous system were examined for increase in blood flow to the extremities. Clinical observations and a one-channel plethysmograph were used to measure arterial dilatation. Seven patients had transcutaneous stimulation applied over the cervical or thoracic spinal cord, peripheral nerves, or low lumbar region; eight had electrical stimulators implanted over the spinal cord in attempts to relieve intractable pain or some of the symptoms of multiple sclerosis; and one patient had electrical stimulators implanted over the C-6 dorsal roots for small artery disease of the upper extremities. Twelve of 13 patients who had electrical stimulation applied to the spinal cord or dorsal roots had significant arterial dilatation in one or more extremities. Electrical stimulation applied to the ulnar nerves did cause arterial dilatation. One patient did not show any change in the central arterial pressure curve during transcutaneous stimulation of the cervical spinal cord.
The lumbar sympathetic chain was electrically stimulated in different species before and after blocking the adrenergic vasoconstrictor nervous response. Blood flow in the hind limb skeletal muscles was measured. In all species studied, fox, sheep, goat, monkey (five different strains), polecat, rat, badger, opossum rat and hare, stimulation of the lumbar chain before adrenergic blockade resulted in a vasoconstriction. After blocking the vasoconstrictor nervous response stimulation elicited a blood flow increase in fox, sheep and goat. After atropine, the response to stimulation was blocked, indicating that sympathetic cholinergic nerves had been activated. In the other species studied no vasodilator response was observed upon sympathetic chain stimulation. The results suggest that the role attributed to the vasodilator nerves, anticipatory to muscle exercise, are played by other mechanisms in species lacking sympathetic cholinergic vasodilator nerves.
1. In anaesthetized cats tetanic contraction of the hind‐limb muscles, elicited by stimulating the ventral roots L6—S1, caused a rise of arterial blood pressure, usually accompanied by small increases in heart rate and pulmonary ventilation: in decerebrate cats, all components of the response were much increased.
2. With tetani of different strengths, obtained by stimulating with different intensities at the same frequency, the pressor response increased with increasing tension.
3. When muscle contraction had been abolished by gallamine, or when dorsal roots L6—S1 had been sectioned, ventral root stimulation no longer caused a pressor response. The response is therefore a reflex, initiated in the exercising limb.
4. The pressor response was not affected by section of all articular nerves to knee and ankle joints, or by section of the vagi. The stimulus therefore originates in the contracting muscles alone.
5. The pressor response is potentiated by occluding the circulation through the working muscles. Reasons are discussed for concluding that the stimulus is chemical rather than mechanical, and that the ‘metabolic receptors’ for this exercise reflex are the free endings of group III and IV sensory nerve fibres located around the blood vessels.
The possibility of sympathetic vasoconstrictor control of blood flow to active muscles was studied in dogs during graded exercise by comparing the blood flow in the normal with that in the Sympathectomized hind limb. Blood flow was measured by electromagnetic flow transducers around each external iliac artery, or inferred from the oxygen saturation of blood samples from the common iliac veins. The dogs either ran for successive periods of 3 minutes at 5.5 km/hr and grades of 0, 7, 14, 21, and 28% or ran each level of exercise separately. Unilateral lumbar sympathectomy (L-2 through L-7) was performed when the flow transducers were implanted or later by a snare technique. The latter allowed observations during exercise as early as 4 hours after sympathectomy. The magnitude of limb blood flow during exercise and the decline of exercise hyperemia were similar in the normal and the sympathectomized limb, as were the changes in the oxygen saturation of limb venous blood. However, electric stimulation of the lumbar sympathetic chain at the L-5 level in the conscious dog by a chronically implanted electrode reduced limb blood flow at all levels of exercise, the maximal flow of 1,000 ml/min was almost halved.
In anesthetized dogs, the vasoconstrictor nerves to the vessels of the hind limb left the spinal cord in the anterior spinal nerve roots from T-10 through L-4 levels. Maximal vasoconstrictor responses occurred on stimulation of the T-12, T-13, and L-l roots; none occurred on stimulation of roots caudal to L-4. The nerves first entered the lumbar paravertebral chain at or above L-1; the last point of entry was at the L-4, L-5 level. No fibers left the lumbar chain at L-1, L-2, and L-3 levels. The first point of exit was at L-4, and nerves continued to leave as far distal as S-1, The most caudal point examined. The maximal response to stimulation of the lumbar chain was at the L-4, L-5 level. With a single exception, the responses to electric stimulation of the anterior spinal nerve roots, lumbar chain, or sympathetic ganglia were confined to the vessels of the ipsilateral limb. In 22 dogs with unilateral sympathectomy (L-2 through L-7), changes in hind-limb vascular resistance were induced reflexly or by electric stimulation of the anterior spinal roots. The results indicated that sympathetic control of the resistance vessels of the hind limb was still absent 77 days after sympathectomy.
The effect of rhythmically performed muscle contractions on blood flow through muscles was investigated in the calf of cat. During a series of contractions, which had led to maximal dilatation of the resistance vessels, a considerable lowering of the pressure in a small vein from the contracting muscles could be demonstrated between contractions, despite the huge inflow. An optimal effect was obtained when the muscle nerve was stimulated with a short (200–300 msec) impulse train once per sec, a pattern mimicking that during running. Rhythmic contractions of this type led to a characteristic blood flow pattern through the muscles. Arterial inflow to the muscle vascular bed occurred only in between contractions, whereas nearly all the venous outflow from the muscles occurred during the contractions.
The venous pressure reduction occurring between contractions implies a gain in effective perfusion pressure and a corresponding augmentation in blood flow through the muscles. Such an effect was found to be considerable in dependent limbs. Here average blood flow through the rhythmically contracting calf muscles could be as great as, or even greater than, the “free” flow in the immediate post‐exercise period. This effect of the “muscle pump” may be of great importance also in the dependent limbs of man.
An acceptable method for measuring phasic coronary velocity and reactive hyperemia in humans has not been available. We have developed a Doppler probe which can be coupled to surface coronary vessels at the time of cardiac surgery with a small suction cup. Phasic coronary velocity can be measured with a signal to noise ratio that exceeds 20:1. Animal studies have shown that the probe does not alter myocardial perfusion or cause tissue damage. In addition, changes in the mean coronary velocity are closely related (r = 0.97) to changes in coronary flow over a wide range (15-400 ml/min). The characteristics of reactive hyperemia in the coronary circulation of dogs determined with the Doppler system are similar to those obtained simultaneously with an electromagnetic flow meter. Transient occlusions of branch coronary vessels in patients with normal coronary arteries are not associated with significant changes in heart rate, left atrial, or mean arterial pressure. The characteristics of reactive hyperemia in normal vessels of 13 patients were as follows: although reactive hyperemia responses were demonstrable following 1 to 2-second coronary occlusions, maximal responses usually occurred with 20-second coronary occlusions; following 20 seconds of coronary occlusion, the ratio of peak to resting velocity was 5.8 ± 0.6 (mean ± SE); the ratio of repayment to debt area was 3.1 ± 0.2, and the duration of the reactive hyperemia response was 20.8 ± 0.3 seconds. These studies provide the first quantitative measurements of coronary reactive hyperemia in humans.
Development of techniques for the continuous measurement of regional blood flow and vascular resistance in intact small animals has been impeded primarily by the bulkiness of flow probes. The availability of an ultrasonic pulsed Doppler flowmeter system enabled us to construct miniaturized probes using 1-mm-diameter piezoelectric crystals that emit a 20-mHz signal and receive the reflected sound waves from passing blood cells. The finished flow probe is approximately 2.5-4 mm long and 2 mm in cross-sectional diameter with lumen diameters appropriate for the rat, ranging from 0.7 to 1.2 mm. This report describes the materials and methods involved in constructing and implanting the probes in rats to monitor renal, mesenteric, and hindquarter blood flow velocity. The accuracy of the pulsed Doppler method in detecting changes in regional blood flow and vascular resistance was established by the demonstration of a highly significant correlation between velocity recorded from the Doppler unit and volume flow recorded simultaneously. These data indicate that the ultrasonic pulsed Doppler flowmeter provides the opportunity to measure changes in regional blood flow and vascular resistance in a conscious freely moving rat.
The majority of afferent nerve fibers in mammalian skeletal muscle are thin myelinated (A delta or group III) and unmyelinated (C or group IV) afferents. Some 50% of these units appear to be responsible for the reception of noxious chemical, mechanical, and thermal stimuli, i.e., they are nociceptors. The other receptive units with fine afferent fibers presumably are activated by moderate innocuous stimuli such as light stretch, contractions, and light local touching. They possibly play a role in the circulatory and respiratory adjustments during exercise, i.e. they may be ergoreceptors. The data presently available suggest that the nociceptive as well as the ergoreceptive units are very heterogeneous groups with diverse receptive properties. The sensitivity of an individual unit may be restricted to the mechanical domain or to a single chemical substance, whereas other receptors respond to a great variety of chemical, mechanical, and probably thermal stimuli. Each receptor, however, seems to have a preferred susceptibility or "dominant sensitivity" to one or the other stimulus. This sensitivity may be modified by various factors, such as the local concentration of prostaglandins or serotonin. The concept of different types of fine afferent units is supported by preliminary ultrastructural findings showing a great structural diversity both in regard to the localization and the structural design of the receptive endings of these afferents.
Previous experiments in the dog have shown that static contractions of the muscles of one limb elicit a reflex increase of resistance in the vessels of the opposite limb, along with an increase of systemic blood pressure. The aim of the present experiments was to examine whether this reflex can cause a redistribution of cardiac output from the resting areas, in favor of the working parts. In 17 anesthetized and ventilated dogs, static contraction of the muscles of the right thigh was elicited with electrodes inserted into these muscles. The carotid sinuses were kept at constant pressure and the vagi cut. During static contractions systemic blood pressure and cardiac output increased by 17.7 +/- 3.1 and 24.2 +/- 5.5%, respectively. The blood flow measured with an electromagnetic flowmeter decreased by 21.9 +/- 5.3% in the femoral artery of the resting limb and increased by 101 +/- 21% in the femoral artery of the "active limb". Data obtained in six dogs with injection of radioactive microspheres during stimulations show that blood flow decreased not only in the muscles of the rising limb (34 +/- 10%), but also in several other resting areas, such as skin (38 +/- 8%), kidney (24 +/- 8%), gut (38 +/- 6%), and tongue (23 +/- 3%). The results show that the reflex under study causes a redistribution of the cardiac output during static muscular contractions.
The central nervous projections of muscle afferents responsible for producing cardiopulmonary responses during muscular exercise were studied in adult cats, rats, and dogs by a combination of neuroanatomical and electrophysiological techniques. Using electrical stimulation of muscle afferents as well as natural stimulation of stretch, pressure, and induced exercise, the authors were able to establish that group III and IV fibers in muscle afferents were most prominently responsible for the cardiopulmonary effects in muscular exercise. These effects were blocked when small diameter fibers were selectively blocked with low concentrations of procaine. In addition, we traced muscle afferents into the central nervous system using the transganglionic transport of horseradish peroxidase (HRP). In the present study it was not possible to expose selectively only those muscle receptors connected to group III and IV fibers; however, the location of sensory nerve terminals in the lumbar cord permitted the authors to distinguish between the different afferent systems. Moreover, although group III and IV afferent fibers in muscle afferents play a predominant role in cardiopulmonary responses in muscular exercise, it is logical to presume that other groups of muscle afferents must be stimulated as well. Our conclusions from these experiments could form a basis for study of afferents of individual afferents using intracellular tracing methods. In their experiments, sensory fibers from muscle were found terminating in laminae I-V of the spinal cord as well as ascending rostrally to terminal in the dorsal column nuclei and in the nucleus of the tractus solitarius. These results suggest that first order afferent fibers from muscle terminate in the major sensory nuclei related to cardiovascular, respiratory, and gastrointestinal control and could provide an anatomical basis for short latency visceral reflex responses mediated by muscle afferents. Following injections of HRP into the medial nucleus of the tractus solitarius (mnTS), they were able to delineate the afferent projections to the brainstem cardiovascular regions. A number of neurons in laminae I-V (medial border) with dendritic arborizations extending into the region of the dorsal column were located on the ipsilateral side. On the contralateral side, neurons were found in laminae IV-VII. The dorsal root ganglia of L7 and S1 spinal roots also showed HRP labeled perikarya, thus indicating the presence of both crossed and uncrossed afferent fiber systems from spinal cord and muscle afferents terminating in the mnTS.
Electrical stimulation effect on localized blood flow
- Currier
Currier DP: Electrical stimulation effect on localized blood flow. Abstract. Phys Ther 63:761, 1983
Measurements of coronary velocity and reactive hyperemia in the coronary circulation of humans Regional blood flow measurement with pulsed Doppler flowmeter in conscious rat
- M Marcus
- C Wright
- D Doty
Marcus M, Wright C, Doty D, et al: Measurements of coronary velocity and reactive hyperemia in the coronary circulation of humans. Circ Res 49:877-891, 1981 20. Haywood JR, Shaffer RA, Fastenow C, et al: Regional blood flow measurement with pulsed Doppler flowmeter in conscious rat. Am J Physiol 241 :H273-H278, 1981
Kjellmer I: On the competition between metabolic vasodilation and neurogenic vasoconstriction in skeletal muscle
Kjellmer I: On the competition between metabolic vasodilation and neurogenic vasoconstriction in skeletal muscle. Acta Physiol Scand
63:450-459, 1965