-
[show abstract]
[hide abstract]
ABSTRACT: PURPOSE: In chronic renal failure, intermittent hemodialysis decreases cerebral blood flow velocity (CBFV); however, in critically ill patients with acute renal failure, the effect of continuous venovenous hemodialysis (CVVHD) on CBFV and cerebrovascular autoregulation (AR) is unknown. Therefore, a study was undertaken to investigate the potential effect of CVVHD on CBFV and AR in patients with acute renal failure. METHODS: This cohort study investigated 20 patients with acute renal failure who required CVVHD. In these patients, the CBFV and index of AR (Mx) were measured using transcranial Doppler before and during CVVHD. RESULTS: The median Mx values at baseline were 0.33 [interquartile range (IQR): 0.02-0.55], and during CVVHD, they were 0.20 [0.07-0.40]. The differences in Mx (CVVHD - baseline) was (median [IQR]) -0.015 [-0.19-0.05], 95% confidence interval (CI) -0.16 to 0.05. The Mx was > 0.3 in 11/20 patients at baseline measurement. Six of these patients recovered to Mx < 0.3 during CVVHD. The CBFV was (median [IQR]) 47 [36-59] cm·sec(-1) at baseline and 49 [36-66] cm·sec(-1) during CVVHD. The difference of CBFV was 0.0 [-4 - 2.7], 95% CI -2.5 to 4.2. CONCLUSION: Compared with patients with intermittent hemodialysis, CVVHD did not influence CBFV and AR in critically ill patients with acute renal failure, possibly due to lower extracorporeal blood flow, slower change of plasma osmolarity, and a lower fluid extraction rate. In a subgroup of patients with sepsis, the AR was impaired at baseline in more than half of the patients, and this was reversed during CVVHD. The trial was registered at ClinicalTrials.gov ID: NCT01376531.
Canadian Anaesthetists? Society Journal 03/2013; · 2.31 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: BACKGROUND:: High levels of positive end-expiratory pressure (PEEP), as part of the treatment in patients with acute respiratory distress syndrome (ARDS), may prevent alveolar collapse and maintain oxygenation. PEEP potentially reduces cerebral venous return, increases intracranial blood volume, and may, therefore, affect cerebral blood flow (CBF) and cerebrovascular autoregulation (AR). This study investigates the effect of PEEP on CBF and AR in patients with respiratory failure. METHODS:: CBF velocity was measured using transcranial doppler and correlated with the invasive arterial blood pressure curve to calculate the index of AR Mx (Mx>0.3 indicates impaired AR). Mx was measured at lower PEEP levels and after increasing PEEP. Only an increase of Mx of >0.2 was considered to be clinically relevant. Two 1-sided Wilcoxon tests. RESULTS:: Twenty mechanically ventilated patients with ARDS were included. Elevation of PEEP from 9.2±1 to 14.3±1 cm H2O did not influence CBF velocity but increased Mx from 0.317±0.35 to 0.414±0.32 (difference ≤0.2). Mx was >0.3 in 11/20 patients during baseline measurements, indicating impaired AR. CONCLUSIONS:: Surprisingly, AR was impaired in 55% of the patients with ARDS. This should be taken into account when managing cerebral perfusion pressure to avoid cerebral hyperperfusion or hypoperfusion. Increasing PEEP from 9.2 to 14.3 cm H2O had no further clinically relevant effect on AR, independent of preexisting AR impairment.
Journal of neurosurgical anesthesiology 11/2012; · 2.41 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: INTRODUCTION: Sepsis-associated delirium (SAD) increases morbidity in septic patients and, therefore, factors contributing to SAD should be further characterized. One possible mechanism might be the impairment of cerebrovascular autoregulation (AR) by sepsis, leading to cerebral hypo- or hyperperfusion in these haemodynamically unstable patients. Therefore, the present study investigates the relationship between the incidence of SAD and the status of AR during sepsis. METHODS: Cerebral blood flow velocity was measured using transcranial Doppler sonography and was correlated with the invasive arterial blood pressure curve to calculate the index of AR Mx (Mx>0.3 indicates impaired AR). Mx was measured daily during the first 4 days of sepsis. Diagnosis of a SAD was performed using the confusion assessment method for ICU (CAM-ICU) and, furthermore the predominant brain electrical activity in electroencephalogram (EEG) both at day 4 after reduction of sedation to RASS >-2. RESULTS: 30 critically ill adult patients with severe sepsis or septic shock (APACHE II 32 +/- 6) were included. AR was impaired at day 1 in 60%, day 2 in 59%, day 3 in 41% and day 4 in 46% of patients; SAD detected by CAM-ICU was present in 76 % of patients. Impaired AR at day 1 was associated with the incidence of SAD at day 4 (p=0.035). CONCLUSIONS: AR is impaired in the great majority of patients with severe sepsis during the first two days. Impaired AR is associated with SAD, suggesting that dysfunction of AR is one of the trigger mechanisms contributing to the development of SAD. Trial registration: clinicalTrials.gov ID NCT01029080.
Critical care (London, England) 10/2012; 16(5):R181. · 4.61 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The beneficial effects of hypertonic saline on neuronal survival and on cerebral blood flow have been shown in several animal models of global and focal brain ischemia. Because of the potential benefits of hypertonic solutions, it is hypothesized that hydroxyethyl starch enhances cerebral blood flow and improves long-term outcome after cardiac arrest and cardiopulmonary resuscitation in an animal model.
Laboratory animal study.
University animal research laboratory.
Fifty-nine male Sprague-Dawley rats.
Rats were randomized to receive either 7.2% saline/6% hypertonic saline hydroxyethyl starch (4 mL/kg) or vehicle (NaCl 0.9 %) after 9 mins of asphyxic cardiac arrest and cardiopulmonary resuscitation. Local cerebral blood flow and physiologic parameters were evaluated during arrest and early restoration of spontaneous circulation. Survival and neurologic assessment were evaluated over a 7-day observation period. Animals received 5-bromo-2-deoxyuridine for 6 days. Neuronal injury and neurogeneration (5-bromo-2-deoxyuridine positive neurons) were quantified on day 7 after cardiac arrest and cardiopulmonary resuscitation.
Hypertonic saline hydroxyethyl starch treatment resulted in an accentuated local cerebral blood flow during early reperfusion, compared to the vehicle group. Animal survival and neurologic outcome were not altered between groups. Neurohistopathological injury was present in hippocampal CA1 and neocortex with no effects of hypertonic saline hydroxyethyl starch on neuronal survival. Increased neurogeneration was found in the dentate gyrus after cardiac arrest/cardiopulmonary resuscitation, which was not influenced by hypertonic saline hydroxyethyl starch administration.
Despite promising results in other models of brain injury, hypertonic saline hydroxyethyl starch failed to improve the outcome when administered after asphyxic cardiac arrest/cardiopulmonary resuscitation in rats. One major difference between the cardiac arrest/cardiopulmonary resuscitation model and other models of brain ischemia is that the effects of asphyxic cardiac arrest involve the whole organism (post-cardiac arrest syndrome) and not exclusively the brain leading to a more severe injury. This might explain why hypertonic saline hydroxyethyl starch has failed to improve outcome in the present model.
Critical care medicine 05/2012; 40(7):2149-56. · 6.37 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: PurposeThis study investigates the effects of S(+)-ketamine and propofol in comparison to sevoflurane on dynamic cerebrovascular
autoregulation in humans.
MethodsTwenty-four patients were randomly assigned to one of the following anesthetic protocols: group I (n = 12): 2.5 mg·kg−1·hr−1 S(+)-ketamine, 1.5–2.5 μg·mL−1 propofol-target plasma concentration; group II (n = 12): 2.0 MAC (4.0 %) sevoflurane. Patients were intubated and ventilated with O2/air (PaO2=0.33). Following 40 min of equilibration dynamic cerebrovascular autoregulation was measured and expressed as the autoregulatory
index (ARI), describing the duration of cerebral hemodynamic recovery in relation to changes in mean arterial blood pressure.
Statistics: Mann-Whitney U test (statistical significance was assumed whenP < 0.05).
ResultsDynamic cerebrovascular autoregulation was intact in all patients with S(+)-ketamine/propofol anesthesia as indicated by an
ARJ of 5.4 ± 1.1. In contrast, dynamic cerebrovascular autoregulation was significantly delayed with 2.0 MAC sevoflurane (ARI
=2.6 ± 0.7).
ConclusionDynamic cerebrovascular autoregulation is maintained with S(+)-ketamine/propofol-based totaliv anesthesia. In contrast, 2.0 MAC sevoflurane delayed dynamic cerebrovascular autoregulation. This supports the use of S(+)-ketamine
in combination with propofol in neurosurgical patients based on its neuroprotective potential along with maintained cerebrovascular
physiology.
ObjectifExaminer les effets de la S(+)kétamlne et du propofol, comparés au sévoflurane, sur l’autorégulatlon vasculalre cérébrale
dynamique chez l’humain.
MéthodeVingt-quatre patients ont été répartis au hasard et ont reçu un des protocoles anesthéslques suivants: groupe I (n = 12):
2,5 mg·kg−1· h−1 de S(+)kétamlne, une concentration plasmatlque cible de propofol de 1,5-2,5μg·mL−1; groupe II (n = 12): 2,0 CAM (4,0 %) de sévoflurane. On a procédé à l’intubation et à la ventilation avec un mélange de O2/alr (PaO2 = 0,33). Après un temps d’équilibre de 40 min, l’autorégulatlon vasculalre cérébrale a été mesurée et exprimée comme l’indice
d’autorégulation (IAR), décrivant la durée de la récupération hémodynamique cérébrale en relation avec les modifications de
la tension artérielle moyenne. Données statistiques: test U de Mann-Whitney (signification statistique avec P < 0,05).
RésultatsL’autorégulatlon vasculalre cérébrale dynamique était Intacte chez tous les patients sous anesthésle avec S(+)kétamlne/propofol
comme l’indiquait un IAR de 5,4 ± 1,1. Par ailleurs, elle a été significativement retardée avec les 2,0 CAM de sévoflurane
(IAR = 2,6 ± 0,7).
ConclusionL’autorégulation vasculalre cérébrale dynamique est maintenue avec une anesthésle exclusivement intraveineuse à base de S(+)kétamlne/propofol
mais retardée avec 2,0 CAM de sévoflurane. Ces données favorisent l’usage de S(+)kétamlne combinée au propofol, en neurochirurgie,
usage fondé sur leur potentiel de neuroprotection et de maintien de la physiologie vasculalre cérébrale.
Canadian Journal of Anaesthesia 04/2012; 48(10):1034-1039. · 2.35 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Since certain surgical procedures still require a sitting or reverse Trendelenburg position, it remains important to evaluate the risk for paradoxical embolization. Intracardiac shunting, the most common cause being a patent foramen ovale, can be excluded by contrast-enhanced transesophageal echocardiography. There are, however, less described cases which result from patency of intrapulmonary functional arteriovenous anastomoses and lead to extra-cardiac paradoxical air embolism during anesthesia. We report a unique case to increase awareness of this real and potentially dangerous complication.
A 52-yr-old male was scheduled for resection of a tumour at the cerebellopontine angle. Preoperative evaluation excluded intracardiac shunts. During a craniotomy in the sitting position, recurrent venous air emboli entered the patient's right heart, leading to a sudden decline in end-tidal CO(2), an increase in PaCO(2), and a reduction of PaO(2). The exact source of surgical entrance could not be identified; therefore, the surgical wound was closed provisionally and the patient was repositioned supine to prevent further venous air emboli. During transition to the supine position, we observed clinically significant crossover of air into the left heart originating from the left pulmonary vein, as detected by transesophageal echocardiography. In all likelihood, the etiology was an opening of intrapulmonary right-to-left anastomoses. The patient recovered without neurological or pulmonary sequelae.
In the presence of massive venous air emboli, intrapulmonary right-to-left paradoxical air emboli can occur while intraoperatively transitioning a patient from the sitting to the supine position.
Canadian Anaesthetists? Society Journal 03/2012; 59(5):478-82. · 2.31 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: To investigate the regulation of the cerebral renin-angiotensin system and the effect of angiotensin II receptor type 1 inhibition on secondary brain damage, cerebral inflammation, and neurologic outcome after head trauma.
The expression of renin-angiotensin system components was determined at 15 mins, 3 hrs, 6 hrs, 12 hrs, and 24 hrs after controlled cortical impact in mice. Angiotensin II receptor type 1 was inhibited using candesartan (0.1, 0.5, 1 mg/kg) after trauma to determine its effect on secondary brain damage, brain edema formation, and inflammation. The window of opportunity was tested by delaying angiotensin II receptor type 1 inhibition for 30 mins, 1 hr, 2 hrs, and 4 hrs. The long-term effect was tested by single and daily repeated treatment with candesartan for 5 days after controlled cortical impact.
University research laboratory.
Male C57Bl/6N mice.
Brain trauma by use of a controlled cortical impact device.
Expression of angiotensin II receptor type 1A decreased by 42% within 24 hrs after controlled cortical impact, whereas angiotensin II receptor type 1B expression increased to 220% between 6 and 12 hrs. Blockage of angiotensin II receptor type 1 with 0.1 mg/kg candesartan within 4 hrs of injury significantly reduced secondary brain damage (30 mins: 25 mm vs. vehicle: 41 mm) and improved neurologic function after 24 hrs but failed to reduce brain edema formation. Daily treatment with candesartan afforded sustained reduction of brain damage and improved neurologic function 5 days after traumatic brain injury compared with single and vehicle treatment. Inhibition of angiotensin II receptor type 1 significantly attenuated posttraumatic inflammation (interleukin-6: -56%; interleukin-1β: -42%; inducible nitric oxide synthase: -36%; tumor necrosis factor-α: -35%) and microglia activation (vehicle: 163 ± 25/mm vs. candesartan: 118 ± 13/mm). Higher dosages (0.5 and 1 mg/kg) resulted in prolonged reduction in blood pressure and failed to reduce brain lesion.
The results indicate that angiotensin II receptor type 1 plays a key role in the development of secondary brain damage after brain trauma. Inhibition of angiotensin II receptor type 1 with a delay of up to 4 hrs after traumatic brain injury effectively reduces lesion volume. This reduction makes angiotensin II receptor type 1 a promising therapeutic target for reducing cerebral inflammation and limiting secondary brain damage.
Critical care medicine 09/2011; 40(3):935-44. · 6.37 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Basic life support (BLS) by laypersons is essential for surviving sudden cardiac death in the community. The present study investigates BLS skill knowledge of German laypersons in a public community place and examines the effect of the interval between the last BLS course and present skills in cardiopulmonary resuscitation (CPR).
Participants were randomly recruited at a public place in a medium-sized German town. Volunteers were confronted with a fictitious cardiac arrest situation using a BLS training manikin and were asked to help. Using a standardised evaluation sheet, measures were documented. Participants' demographic data were evaluated after completion of the scenario.
None of the participants (n=89; male=42, female=47) followed the current BLS algorithm correctly; independent from the last CPR course was attended. Most steps were performed in random order. 43% (n=38) of participants checked for responsiveness, 65% (n=58) performed chest compressions, and 63% (n=56) delivered rescue breathing. 10% (n=9) of participants were unable to name a national emergency telephone number. Laypersons who attended a BLS course more than 10 years ago showed a significant lack of BLS knowledge and failed more often to deliver chest compressions and rescue breathing.
The present study demonstrates that current CPR guidelines for BLS are not followed by laypersons in a medium-sized town in Germany. These data suggest that CPR refresher courses as well as implication of BLS guidelines in daily life are warranted.
Emergency Medicine Journal 09/2011; 28(9):786-9. · 1.44 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: BACKGROUND: Accidental vessel occlusion is one major risk of intracranial aneurysm surgery potentially causing cerebral ischemia. The intraoperative assessment of cerebral ischemia remains a technological challenge.
OBJECTIVE: As a novel approach, cortical tissue integrity was monitored using simultaneous measurements of regional capillary-venous cerebral blood flow (rvCBF), oxygen saturation (Srvo2), and hemoglobin amount (rvHb) during aneurysm surgery.
METHODS: Fifteen patients scheduled for aneurysm surgery of the anterior and posterior circulation were included. A fiber optic probe was placed on the cortex associated with the distal branch of the aneurysmatic vessel. Blinded measurements by combined laser-Doppler flowmetry (rvCBF) and photospectrometry (Srvo2, rvHb) were performed before and after surgical clipping or trapping of the aneurysm. Data were correlated with postoperative imaging and neurological outcome.
RESULTS: Cortical measurements could be successfully performed in all patients. Significant increase (>25% change from baseline) or decrease (<25% change from baseline) of rvCBF, Srvo2, and rvHb was detectable in 33 to 46% of patients after surgical intervention. Severe decrease (>50% change from baseline) of all parameters or solitary of rvCBF was correlated to reduced cerebral perfusion and neurological deficits in 2 patients.
CONCLUSION: Combined laser-Doppler flowmetry and photospectrometry provides real-time information on cortical microcirculation. Intraoperative alterations of parameters (rvCBF, Srvo2, rvHb) might reflect changes of cerebral tissue integrity during intracranial aneurysm surgery.
Neurosurgery 07/2011; 69(2):391-398. · 2.79 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Autologous blood transfusion (ABT), for example, by means of cell saver equipment, is used to reduce the need for allogenic blood transfusion in patients with high perioperative blood loss. This study investigated the effect of blood/extracorporal surface interaction during withdrawal and retransfusion of shed autologous blood on cerebral inflammation in rats. Rats subjected to hypotension with cerebral ischemia served as positive controls.
Eighty-eight male Sprague-Dawley rats were anesthetized with sevoflurane, instrumented, and randomly assigned to the following groups: sham-operation (SHAM), autologous blood withdrawal/transfusion only (ABT), or bilateral carotid artery occlusion and autologous blood withdrawal/transfusion (BCAO/ABT). Inflammatory gene expression was investigated with real-time RT-polymerase chain reaction at 6, 12, and 24 hours after SHAM, ABT, or BCAO/ABT in brain hippocampal tissue. Naive rats were investigated as reference.
ABT alone had no impact on hippocampal inflammatory gene expression, whereas after BCAO/ABT tumor necrosis factor-alpha (10.7 fold at 24 h), interleukin-1β (2.1 fold at 6 h), interleukin-6 (35.7 fold at 24 h), COX-2 (9.3 fold at 6 h), and inducible nitric oxide synthase (3.4 fold at 24 h) increased compared with SHAM.
ABT by itself did not provoke an inflammatory reaction in the healthy brain. However, in combination with cerebral ischemia the induction of a broad spectrum of inflammatory parameters indicates an inflammatory reaction of the hippocampus beginning after 6 hours and being most pronounced after 24 hours. Therefore, this study shows that cerebral inflammation is not induced by ABT after contact with extracorporal surfaces in rats.
Journal of neurosurgical anesthesiology 07/2011; 23(3):215-21. · 2.41 Impact Factor
-
Steven Backman,
Andrew Baker,
Scott Beattie,
Penelope Brasher,
Gregory Bryson,
Davy Cheng,
Mark Crawford,
Alain Deschamps,
François Donati,
Pierre Drolet, [......],
Alan Merry,
Donald R Miller,
David Moher,
Patricia Morley-Forster,
Benoit Plaud,
Roanne Preston,
Saifee Rashiq,
Robert Sladen,
Ban Tsui, Christian Werner
Canadian Anaesthetists? Society Journal 07/2011; 58(7):668-696. · 2.31 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Inflammatory and ischemic processes contribute to the development of secondary brain damage after mechanical brain injury. Recent data suggest that thiazolidinediones (TZDs), a class of drugs approved for the treatment of non-insulin-dependent diabetes mellitus, effectively reduces inflammation and brain lesion by stimulation of the peroxisome proliferator-activated receptor-γ (PPAR-γ). The present study investigates the influence of the TZD pioglitazone and rosiglitazone on inflammation and secondary brain damage after experimental traumatic brain injury (TBI). A controlled cortical impact (CCI) injury was induced in male C57BL/6 mice to investigate following endpoints: (1) mRNA expression of PPAR-γ and PPAR-γ target genes (LPL, GLT1, and IRAP/Lnpep), and inflammatory markers (TNF-α, IL-1β, IL-6, and iNOS), at 15 min, 3 h, 6 h, 12 h, and 24 h post-trauma; (2) contusion volume, neurological function, and gene expression after 24 h in mice treated with pioglitazone (0.5 and 1 mg/kg) or rosiglitazone (5 and 10 mg/kg IP at 30 min post-trauma); and (3) the role of PPAR-γ to mediate protection was determined in animals treated with pioglitazone, the PPAR-γ inhibitor T0070907, and a combination of both. Inflammatory marker genes, but not PPAR-γ gene expression, was upregulated after trauma. Pioglitazone reduced the histological damage and inflammation in a dose-dependent fashion. In contrast, rosiglitazone failed to suppress inflammation and histological damage. PPAR-γ and PPAR-γ target gene expression was not induced by pioglitazone and rosiglitazone. In line with these results, pioglitazone-mediated protection was not reversed by T0070907. The results indicate that the neuroprotective effects of pioglitazone are not solely related to PPAR-γ-dependent mechanisms.
Journal of neurotrauma 06/2011; 28(6):983-93. · 4.25 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Volatile anesthetics reduce postischemic neurohistopathological injury and improve neurological outcome in various animal models. However, the isoflurane concentrations above 1 minimum alveolar concentration (MAC) have been associated with reduced neuronal survival and impaired functional outcome. The aim of this study was to evaluate if 1.8 MAC sevoflurane alters postischemic neuronal survival and neurologic outcome compared with 0.45 MAC sevoflurane.
In this study, 20 fasted male Sprague-Dawley rats were randomly assigned to treatment groups with 1 or 4 vol.% sevoflurane end-tidal concentration. Cerebral ischemia was induced by bilateral carotid artery occlusion and hemorrhagic hypotension (BCAO). The cognitive outcome was assessed after 7 days using the object recognition test. Animals were then re-anesthetized and brains were removed for neurohistopathological analysis of the hippocampus (CA1) and cortex using hematoxylin-eosin staining.
Physiologic parameters were not different between both the treatment groups. The number of viable neurons (median [Q1, Q3]) in the CA1 region on postischemic day 7 was increased after high-dose sevoflurane compared with low-dose sevoflurane (1645 [453, 1825] vs. 3222 [2920, 3993] neurons/ROI, P < 0.05). Results of the object recognition test were not different between both the treatment groups.
Postischemic neuronal survival was increased with 1.8 MAC compared with 0.45 MAC sevoflurane. Therefore, experimental models of cerebral ischemia should account for neuroprotective effects of sevoflurane with increasing concentrations. To ensure minimal interference of sevoflurane on neuronal survival, a low inspired concentration should be used and fluctuations in the depth of anesthesia should be limited.
Neurocritical Care 05/2011; 15(3):577-84. · 2.47 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Abstract Background Out-of-hospital endotracheal intubation performed by paramedics using the Macintosh blade for direct laryngoscopy is associated with a high incidence of complications. The novel technique of video laryngoscopy has been shown to improve glottic view and intubation success in the operating room. The aim of this study was to compare glottic view, time of intubation and success rate of the McGrath® Series 5 and GlideScope® Ranger video laryngoscopes with the Macintosh laryngoscope by paramedics. Methods Thirty paramedics performed six intubations in a randomised order with all three laryngoscopes in an airway simulator with a normal airway. Subsequently, every participant performed one intubation attempt with each device in the same manikin with simulated cervical spine rigidity using a cervical collar. Glottic view, time until visualisation of the glottis and time until first ventilation were evaluated. Results Time until first ventilation was equivalent after three intubations in the first scenario. In the scenario with decreased cervical motion, the time until first ventilation was longer using the McGrath® compared to the GlideScope® and AMacintosh (p < 0.01). The success rate for endotracheal intubation was similar for all three devices. Glottic view was only improved using the McGrath® device (p < 0.001) compared to using the Macintosh blade. Conclusions The learning curve for video laryngoscopy in paramedics was steep in this study. However, these data do not support prehospital use of the McGrath® and GlideScope® devices by paramedics.
Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine. 01/2011;
-
[show abstract]
[hide abstract]
ABSTRACT: It is unclear whether a single, brief, 15-minute episode of background anesthesia already modulates delayed secondary processes after experimental brain injury. Therefore, this study was designed to characterize three anesthesia protocols for their effect on molecular and histological study endpoints. Mice were randomly separated into groups that received sevoflurane (sevo), isoflurane (iso) or an intraperitoneal anesthetic combination (midazolam, fentanyl and medetomidine; comb) prior to traumatic brain injury (controlled cortical impact, CCI; 8 m/s, 1 mm impact depth, 3 mm diameter). Twenty-four hours after insult, histological brain damage, neurological function (via neurological severity score), cerebral inflammation (via real-time RT-PCR for IL6, COX-2, iNOS) and microglia (via immunohistochemical staining for Iba1) were determined. Fifteen minutes after CCI, the brain contusion volume did not differ between the anesthetic regimens (sevo = 17.9±5.5 mm(3); iso = 20.5±3.7 mm(3); comb = 19.5±4.6 mm(3)). Within 24 hours after injury, lesion size increased in all groups (sevo = 45.3±9.0 mm(3); iso = 31.5±4.0 mm(3); comb = 44.2±6.2 mm(3)). Sevo and comb anesthesia resulted in a significantly larger contusion compared to iso, which was in line with the significantly better neurological function with iso (sevo = 4.6±1.3 pts.; iso = 3.9±0.8 pts.; comb = 5.1±1.6 pts.). The expression of inflammatory marker genes was not significantly different at 15 minutes and 24 hours after CCI. In contrast, significantly more Iba1-positive cells were present in the pericontusional region after sevo compared to comb anesthesia (sevo = 181±48/mm(3); iso = 150±36/mm(3); comb = 113±40/mm(3)). A brief episode of anesthesia, which is sufficient for surgical preparations of mice for procedures such as delivering traumatic brain injury, already has a significant impact on the extent of secondary brain damage.
PLoS ONE 01/2011; 6(5):e19948. · 4.09 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Out-of-hospital endotracheal intubation performed by paramedics using the Macintosh blade for direct laryngoscopy is associated with a high incidence of complications. The novel technique of video laryngoscopy has been shown to improve glottic view and intubation success in the operating room. The aim of this study was to compare glottic view, time of intubation and success rate of the McGrath® Series 5 and GlideScope® Ranger video laryngoscopes with the Macintosh laryngoscope by paramedics.
Thirty paramedics performed six intubations in a randomised order with all three laryngoscopes in an airway simulator with a normal airway. Subsequently, every participant performed one intubation attempt with each device in the same manikin with simulated cervical spine rigidity using a cervical collar. Glottic view, time until visualisation of the glottis and time until first ventilation were evaluated.
Time until first ventilation was equivalent after three intubations in the first scenario. In the scenario with decreased cervical motion, the time until first ventilation was longer using the McGrath® compared to the GlideScope® and AMacintosh (p < 0.01). The success rate for endotracheal intubation was similar for all three devices. Glottic view was only improved using the McGrath® device (p < 0.001) compared to using the Macintosh blade.
The learning curve for video laryngoscopy in paramedics was steep in this study. However, these data do not support prehospital use of the McGrath® and GlideScope® devices by paramedics.
Scandinavian Journal of Trauma Resuscitation and Emergency Medicine 01/2011; 19(1):4. · 1.85 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In patients with neuronal injury, the knowledge of the status of cerebrovascular autoregulation can help to optimize the management of the cerebral perfusion pressure. This study characterizes dynamic and static cerebrovascular autoregulation during the first 7 days after severe traumatic brain injury or intracranial hemorrhage.
After approval from the IRB, 16 patients were studied. Cerebral blood flow velocity (CBFV) was measured daily for the assessment of dynamic (10 patients) and static (16 patients) cerebrovascular autoregulation in both the middle cerebral arteries using the transcranial Doppler sonography. Dynamic cerebrovascular autoregulation (dAR) was measured using the cuff-deflation method and was expressed by the index of the dAR. The index of the static cerebrovascular autoregulation (sAR) was calculated from changes in the CBFV in relation to drug-induced alterations of the arterial blood pressure. For statistical analyses, t test and mixed effect model were used.
Both dAR and sAR after brain injury were impaired in most of the patients. The chronologic sequence of the dAR at the ipsilateral injured hemisphere showed a significant decrease until day 4 followed by an incomplete recovery (P < 0.002). Changes in sAR were similar, however, they did not gain statistical significance. CBFV was lower at day 1-2 after injury in comparison with day 4 to 7 (P < 0.02).
Daily measured dAR and sAR were impaired after brain injury with a nadir on day 4 and consecutive incomplete recovery over time.
Journal of neurosurgical anesthesiology 01/2011; 23(1):41-4. · 2.41 Impact Factor
-
Circulation 01/2011; 124(21, S}, Meeting Abstract = {A197). · 14.74 Impact Factor
-
Christian Werner
Best practice & research. Clinical anaesthesiology. 12/2010; 24(4):vii-x.
-
Journal of neurosurgical anesthesiology 10/2010; 22(4):372. · 2.41 Impact Factor
