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Combined effect of catheter and tubing size on fluid flow


Abstract and Figures

Several studies have evaluated the effect of large-bore tubing and various intravenous (IV) catheters on rapid fluid resuscitation. This study combines available equipment, which has been demonstrated to increase IV flow rate, into a system. This system is then compared with one commonly used for IV fluid infusion in hypovolemic patients. The new system requires significantly less (P less than 0.0005) time for both drainage of fluid and changing of IV containers. The improvement in flow rate can be attributed to the use of a rapid inflation/deflation pneumatic pressure device instead of the conventional hand-pumped pressure bag and the decrease in resistance through both the large-bore IV tubing and 12-gauge catheter. The rapid manipulation of IV bags is made possible by the rigid structure and the rapid inflation/deflation ability of the external pump. The possibility of faster change of IV bags and an increase in flow rate make this system a practical tool in the treatment of severely hypovolemic patients.
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Clinical Notes
Combined Effect of Catheter and Tubing Size on
Fluid Flow
Several studies have evaluated the effect of large-bore tubing
and various intravenous (IV) catheters on rapid fluid resuscita-
tion. This study combines available equipment, which has been
demonstrated to increase IV flow rate, into a system. This system
is then compared with one commonly used for IV fluid infusion in
hypovolemic patients. The new system requires significantly less
(P < 0.0005) time for both drainage of fluid and changing of IV
containers. The improvement in flow rate can be attributed to the
use of a rapid inflation/deflation pneumatic pressure device in-
stead of the conventional hand-pumped pressure bag and the de-
crease in resistance through both the large-bore IV tubing and
12-gauge catheter. The rapid manipulation of IV bags is made
possible by the rigid structure and the rapid inflation/deflation
ability of the external pump. The possibility of faster change of IV
bags and an increase in flow rate make this system a practical
tool in the treatment of severely hypovolemic patients. (Am J
Emerg Med 1988;4:238-240)
Successful resuscitation of the exsanguinating pa-
tient is dependent upon rapid venous access followed
by volume replacement. The literature is replete with
ideas both to improve venous access1.2 and to increase
intravenous (IV) flow rates. Methods suggested to in-
crease fluid flow include utilizing experimental de-
vices,3 altering the use of available equipment,4 imple-
menting newly available equipment, (e.g., large-bore
tubing),5 and utilizing pneumatic external pressure de-
The purpose of this study was to combine available
equipment, which has been demonstrated to increase
IV flow rates, into a system. The efficacy of this
system could then be compared with one commonly
utilized for IV infusion in hypovolemic patients. In
addition, we measured the learning needed to utilize
both systems effectively in vitro.
From the Section of Emergency Medicine. Arizona Health
Sciences Center, University of Arizona, Tucson, Arizona 85724.
Manuscript received October 4 1985; accepted November 7,
Address reprint requests to Dr. Iserson.
Key Words: Catheter, flow rate, intravenous, rapid fluid resusci-
tation, tubing.
Two IV fluid systems were compared. The first
system (system I) consisted of large-bore IV fluid
tubing (Fenwal Laboratories, Deerfield, Illinois;
#4C2137), a rapid inflation/deflation pneumatic ex-
ternal pressure device (Infusor -I “, patent
#4,.539,005. Aspen Labs, Englewood, Colorado) ar-
ranged in a parallel configuration and connected to a
wall air source,h and a 12-gauge. &cm-long Teflon:‘” IV
catheter (Vygon Laboratories Pharmaceutiques, BP-7
95440, Ecoven, France). The second system (system
II) consisted of standard-bore IV fluid tubing (McGaw
Labs, Puerto Rico: #V 14 15). a hand-pumped external
pressure bag (Fenwal Laboratories, Deerfield, Illinois:
Code 4R 4403) and a l4-gauge. 5.7-cm-long Teflon@ IV
catheter (Quik-Cath@. Travenol Laboratories, Deer-
field, Illinois).
The two IV fluid systems were compared by mea-
suring the time required to drain two l-liter bags, the
take-down/set-up time between utilization of the two
bags, and the total infusion time. Each trial was re-
peated by each study participant five times in succes-
There were eight nurse participants in this study.
These individuals had varying amounts of prior expe-
rience utilizing the pressure devices. Each nurse in-
flated the pressure device (pneumatic or hand-
pumped) to 300 mm Hg and maintained it at that level.
Following drainage and take-down of the first fluid
container. the second liter of fluid was set-up and
drained. The participants were instructed to use any
combination of fluids from the two bags to total 1,800
ml. Each two-bag drainage was considered a new trial
and recorded separately.
Each bag was filled with 1,000 ml of water. utilizing
an additive pump. This pump measures exact amounts
of fluid when preparing special IV solutions.
The experimental design allowed evaluation of the
overall learning curve for each nurse participant. It
also allowed evaluation of the interaction between
each nurse and the various types of equipment used in
the study.
Frequency distributions, means. and standard de-
TABLE 1. Mean Time (minutes:seconds) for Two Fluid Systems
Pump-up/Drain Take-down/
(1st liter) Set-up
(min:sec) (mln:sec)
(2nd liter)
Total Time
Flow Rate
System I (large-bore,
pneumatic pressure device)
System II (standard-bore,
hand-pumped device)
P values
1:16 0:22 1:lO 2:48 640
4:19 1:3? 3:37 9:33 190
<0.0005 <0.0005 <0.0005 <0.0005 <0.0005
viations were generated for each component of the
study (i.e., pump up/drain first liter, take down first
bag/set up second bag, pump up/drain second liter.
and total time). Analysis of variance (ANOVA) was
utilized to determine statistical significance between
the components, the nurses, and the devices. Analysis
by univariate model with repeated measures of
ANOVA was the method for determining the amount
of learning from the replications.
Each of the study participants, independent of ex-
perience, recorded similar times when using system I
(rapid inflation/deflation pneumatic pressure device,
large-bore tubing, 12-gauge catheter). The range of
times needed for the study participants to infuse 1.800
ml of fluid across all the trials ranged from 2:35
(min:sec) to 3:04.
When the nurses utilized system II (hand-pumped
pressure bag, standard-bore tubing, ICgauge catheter)
to infuse 1,800 ml of fluid, the range of times increased
significantly (P < 0.0005) (Table 1). The total time re-
quired to drain the fluid with this system ranged from
7:45 to I1:39.
No learning effect was identified overall or for any
individual nurse utilizing either system.
Severe hypovolemia is a life-threatening emergency,
and fluid resuscitation must begin immediately upon
its diagnosis. The rate of fluid replacement is vital to a
TABLE 2. Intravenous Fluid Viscosities.
Water 1.00 x 10-2
Lactated Ringers’ 1.00 x lo-’
Normal saline 1.01 x 10-2
Dextrose So/&/water 1.10 x to-*
Dextrose 5%/normal saline 1.11 x 10-2
Dextrose 5%/lactated Ringers’ 1.12 x 10-2
* Viscosities are calculated at 25°C (from U.S. Pharmacopeial
Convention Committee of Revision. The United States Pharma-
copeia, 20th revision, Rockville, Maryland: US. Pharmacopeial
Convention, Inc., 1980:987).
successful outcome. Numerous studies have demon-
strated that altering the IV tubing size, catheter size,
or both, with and without an external pressure source,
creates a high fluid flow rate.4-7 This study has com-
bined an easy-to-use pneumatic pressure device with a
commercially available large-bore tubing and a 12-
gauge IV catheter to form a readily available. effi-
cient, and rapid fluid delivery system.
The flow rates, when utilizing system I to drain
1,800 ml of fluid, ranged from 590 ml/min to 700 ml/
min. This represents less than a minute’s difference
among all eight study participants. Several reasons
can be identified for this: 1) since the pneumatic de-
vice fills and releases pressure rapidly and the IV bags
are inserted more easily because the apparatus is rigid
and contains a door, valuable time is not consumed in
changing the empty IV bags: 2) the problem of leakage
from pressure devices, which often requires multiple
personnel for monitoring, is eliminated because of a
continuous wall source of air: 3) the combination of
large-bore tubing and large-gauge catheter decreases
the resistance to flow that is found in other tubing/
catheter combinations.
This system allows for optimal use of limited per-
sonnel, minimizes time to successfully complete the
resuscitation, and allows maximum use of each IV
site. Although use of the entire system is the most sig-
nificant here, utilization of individual components can
improve any fluid system.
In contrast, the flow rates achieved with system II
ranged from 155 ml/min to 230 ml/min. This repre-
sented nearly a 4-minute difference between study
participants to drain 1,800 ml of fluid. It also demon-
strated a 435 ml/min to 470 ml/min slower rate of flow
than with system I. Reasons for these findings in-
clude the following. 1) An extensive amount of time is
needed to change the IV bags because the hand-
pumped pressure bag does not easily deflate between
uses to allow insertion of a new fluid container. 2) De-
spite using new hand-pumped bags in the study, a
constant pressure of 300 mm Hg could not be main-
tained. Additional pressure needed to be added to the
pressure bags throughout the trials, as is often the
case during actual resuscitations. This need for addi-
tional pressure requires additional personnel to mon-
itor the pressure bags. 3) Smaller tubing and catheter
size increases fluid turbulence, thereby decreasing
flow rates. 4,5
All of the nurse participants adapted to both ex-
ternal pressure systems without any start-up learning
problems. This was evidenced by a flat learning curve
on data analysis.
Some problems have been identified with large-bore
IV infusion systems. The large external diameter of
I2-gauge catheters may make placement difficult in el-
derly or severely volume-depleted patients. However,
in the hands of a skilled operator, placement is only
slightly more complicated than a regular 1V catheter.4
The potential for fluid overload also exists with rapid
fluid infusion systems. Utilization of these systems re-
quire close monitoring of infused volume and the pa-
tient’s physiological response to the infusion. Hypo-
thermia, induced by the use of room-temperature or
cold fluids, must also be closely monitored. Main-
taining a supply of previously warmed electrolyte so-
lutions can partially alleviate this potentially dan-
gerous problem.
To universalize this study to various resuscitation
protocols and variations in treatment regimens, water
was utilized as the study fluid. Water has a viscosity
of 1 .O x lo-* stoke.8 The results, therefore, are easily
extrapolated to other IV solutions utilized during re-
suscitations (Table 2).
The rapid-flow IV fluid delivery system, comprising
a 12-gauge catheter, large-bore tubing, and an external
pneumatic pressure device, is a new tool to be used in
the treatment of severely hypovolemic patients, both
in the hospital and pre-hospital environments. Its ease
of use, significantly higher flow rate, and effective de-
crease in personnel requirements should make this a
welcome addition to the armamentarium for fluid re-
1. Dailey R. Use of wire-guided (Seldinger-type) catheters in the
emergency department. Ann Emerg Med 1983;8:489-
2. Haynes B, Carr F, Neimann JT. Catheter introducers for rapid
fluid resuscitation. Ann Emerg Med 1983;10:606-609,
3. lserson K, Reeter A. Rapid fluid replacement: A new method-
ology. Ann Emerg Med 1984;2:97-100.
4. Millikan J. Cain T, Hansbrough J. Rapid volume replacement
for hypovolemic shock: A comparison of techniques and
equipment. J Trauma 1984;5:428-431.
5. lserson K, Reeter AK, Criss E. Comparison of flow rates for
standard and large-bore tubing. West J Med
6. lserson K, Reeter A, Wood W, et al. Pressurization of IV bags:
A new configuration and evaluation for use. J Emerg Med
7. Mateer J, Thompson B, Tucker J, et al. Effects of high pres-
sure and large-bore tubing on IV flow rates. Am J Emerg
Med 1985;3:187-189.
8. U.S. Pharmacopeial Convention Committee of Revision. The
United States Pharmacopeia, 20th revision. Rockville,
Maryland: U.S. Pharmacopeial Convention. Inc.;
... Commonly, gravity or pressure infusion is used in emergency departments for fluid resuscitation, but its low flow rate and the demand for more service members limit its applications especially in military and civilian settings. 6 Alternatively, in-line mechanical infusion pumps can be used in the administration of blood products. They are typically driven by a step motor that moves several circularly arranged rollers. ...
... In the test, each sample of 5 mL taken respectively from the PRBCs before and after transfusion was prepared to extract the supernatant fluid with fHb content by separation of red cells using a Centrifuge. By measuring the absorbance of the supernatant fluid, we can obtain the concentration of the fHb solution in accordance with the above equations (5) and (6). Finally, the hemolysis of this system can be evaluated. ...
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A rapid infusion pump with a maximum flow rate of 6 L/h was designed experimentally using a micro electromagnetic linear actuator, and its effectiveness was evaluated by comparing with that of a commercial Power Infuser under preset flow rates of 0.2, 2, and 6 L/h. The flow rate, air detection sensitivity, occlusion response time, quantitative determination of hemolysis, and power consumption of the infusion devices were extensively investigated using statistical analysis methods (p < 0.05). The experimental results revealed that the flow rate of the designed infusion pump was more stable and accurate, and the hemolysis was significantly less than that of the Power Infuser. The air detection sensitivity and the power consumption could be comparable to that of the Power Infuser except the occlusion response time. The favorable performance made the designed infusion pump a potential candidate for applications in pre-hospital fluid administration. © IMechE 2015.
... -Augmenter le diamètre interne des tubulures tout en tenant compte de leur volume interne [Millikan JS 1984, Mateer JR 1985, Iserson KV 1985, Iserson KV 1986, Dutky PA 1989, Noirot MT 1990, Landow L 1990]. ...
... -Augmenter le diamètre des cathéters tout en tenant compte du volume interne des dispositifs [Hodge D 1985, Iserson KV 1986, Philip BK 1986, Rosen KR 1986, Jones BR 1992, Elad D 1994, Stoneham 1995. ...
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Intravenous (IV) infusion is a common medical act in clinical wards, although not without risk. Many factors affect drug delivery rate (or drug mass flow rate), especially medical devices used to administer one or more drugs. By their very features, these devices may generate more or less significant variations in drug mass flow rate during infusion.The first part of this work consisted in analysing published literature dealing with the impact of medical devices on drug mass flow rate when delivered intravenously. This systematic review revealed mainly in vitro studies on all factors likely to alter the flow rate or concentration of the drug infused.The first stage of our experimental work is dedicated to preventing hazardous disturbances in the mass flow rate of the drug solution infused intravenously to the patient. It showed in vitro the ability of a new multi-lumen infusion access device with a very low internal volume (Multiline-8, Doran International, France) to prevent such disturbances in drug delivery in the context of multi-infusion therapy and when interrupting and resuming carrier fluid flow. The second stage demonstrated in vitro the impact of infusion set characteristics on the accuracy of morphine doses in patient-controlled analgesia. The use of a low dead space volume Y-set significantly improved the accuracy of the morphine dose delivered during bolus and reduced morphine infusion during lockout intervals. Thus, the use of infusion devices with a very low internal volume minimises variations in drug mass flow rate and consequently, clinical impact.The second part of our work focused on the prevention of drug incompatibilities when several treatments are administered simultaneously. The first task accomplished on this topic showed in vitro the ability of multi-lumen infusion access devices to prevent the occurrence of physicochemical incompatibility between two drugs known to be incompatible (furosemide/midazolam). Our results indicate that three factors impact on physical compatibility between drugs: drug concentration, carrier flow rate and the design of the infusion device. Our main hypothesis is that fluid dynamics differ according to infusion devices which modify contact time between the two drugs and saline. The second task was an in vitro quantification of drug loss in the case of drug incompatibility using the example of furosemide and midazolam. Our study revealed that physical incompatibility between two drugs can lead to a significant reduction in drug delivery to the patient, even in the absence of visible particles. Indeed, furosemide precipitation resulting in the formation of visible and/or sub-visible particles led to a drug loss to the patient estimated at between 10% and 15% when midazolam was present. Preventing incompatibilities is a major challenge to ensure the safety and effectiveness of injectable drugs.The results of the whole of our in vitro studies must be validated in a clinical setting to determine the extent to which the choice of device affects the efficiency and safety of IV therapeutics administered to the patient.
... Unfortunately, it may not be possible to establish a large-bore peripheral IV access for many patients who present in shock. Additionally, the amount of time required to set up the IV access, maintain constant pressure, and perform bag changes during the chaotic and resource-limited clinical setting is often underestimated [56]. Furthermore, life-threatening air embolism can occur if all air has not been removed from the IV fluid container prior to infusion [57][58][59]. ...
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Purpose of Review This review provides historical context and an update on recent advancements in volume resuscitation for circulatory shock. Emergency department providers who manage critically ill patients with undifferentiated shock will benefit from the insights of early pioneers and an overview of newer techniques which can be used to optimize resuscitation in the first minutes of care. Recent Findings Rapid infusion of fluids and blood products can be a life-saving intervention in the management of circulatory and hemorrhagic shock. Recent controversy over the role of fluid resuscitation in sepsis and trauma management has obscured the importance of early and rapid infusion of sufficient volume to restore circulation and improve organ perfusion. Evidence from high-quality studies demonstrates that rapid and early resuscitation improves patient outcomes. Summary Current practice standards, guidelines, and available literature support the rapid reversal of shock as a key priority in the treatment of hypotension from traumatic and non-traumatic conditions. An improved understanding of the physiologic rationale of rapid infusion and the timing, volume, and methods of fluid delivery will help clinicians improve care for critically ill patients presenting with shock. Clinical Case A 23-year-old male presents to the emergency department (ED) after striking a tree while riding an all-terrain vehicle. On arrival at the scene, first responders found an unconscious patient with an open skull fracture and a Glasgow coma scale score of 3. Bag-valve-mask (BVM) ventilation was initiated, and a semi-rigid cervical collar was placed prior to transport to your ED for stabilization while awaiting air transport to the nearest trauma center. You are the attending emergency medicine physician at a community ED staffed by two attending physicians, two physicians assistants, and six nurses covering 22 beds. On ED arrival, the patient has no spontaneous respiratory effort, and vital signs are as follows: pulse of 140 bpm, blood pressure of 65/30 mmHg, and oxygen saturation 85% while receiving BVM ventilation with 100% oxygen. He is bleeding profusely through a gauze dressing applied to the exposed dura. The prehospital team was unable to establish intravenous access. What are the management priorities for this patient in shock, and how should his hypotension best be addressed?
Objectives To evaluate the maximum in vitro flow rate of 6 types of polyurethane over-the-wire double lumen catheters using both ports, for high volume fluid resuscitation in large animal species. Settings University teaching hospital. Design Prospective in vitro experimental study. Interventions The flow rate of both ports of 6 polyurethane double lumen over-the-wire catheters (11 and 13–Fr, 15 and 20 cm long, elliptical and tapered tip designs) and 2 types of infusion (with or without pressure bags) were tested on a factorial scheme (6 × 2) in triplicate, using commercial isotonic crystalloid (0.9% NaCl) and synthetic colloid (6% Hydroxyethyl starch, 130/0.4). Measurements and main results Flow rates were influenced by catheter diameter, length, tip design and presence or absence of pressure bags (P < 0.05). Mean flow rates during non-pressurized 0.9% NaCl infusion ranged from 584 mL/min (35 L/h; 11-Fr x 15 cm x tapered tip catheter) to 905 mL/min (54 L/h; 13-Fr x 15 cm x elliptical tip catheter). Mean flow rates during non-pressurized synthetic colloid infusion varied from 404 mL/min (24 L/h; 11-Fr x 15 cm x tapered tip catheter) to 724 mL/min (43 L/h; 13-Fr x 15 cm x elliptical tip catheter). Mean flow rates during pressurized infusion were 1.72 and 2.02 times greater than those obtained by gravity alone for 0.9% NaCl and synthetic colloid, respectively (P < 0.05). Conclusions Highest in vitro flow rates were achieved when larger diameter, shorter and elliptical tip catheters were used during 0.9% NaCl infusion. Catheter diameter, tip design but not length influenced the flow rate during synthetic colloid infusion. The use of pressure bags significantly increased the flow rate of all catheters, for both solutions.
BACKGROUND The physics of ideal fluid flow is well characterized. However, the effect of catheter size, tubing types, injection port adjuncts, and viscosity on flow is not well described. We used a simulated environment to determine how various permutations of common elements affect fluid flow. STUDY DESIGN AND METHODS We tested 16 peripheral and central venous catheters to assess flow through several standard infusion sets and a rapid infuser set; tested flow through standard and blood infusion sets with the addition of intravenous extension tubing, stopcocks, and a needleless connector; and compared the relative viscosity of commonly used blood products and colloids to that of normal saline. RESULTS The maximal flow rate was 200 mL/min for the standard infusion set but 800 mL/min for the rapid infusion set. Choice of infusion tubing was the rate‐limiting component for many larger catheters. A 14‐gauge, single‐lumen central venous catheter (CVC) and 18‐gauge peripheral intravenous catheter (PIV) had equivalent flow rates with all infusion sets. A 16‐gauge single‐lumen CVC allowed a flow rate that was slower than that of a 20‐gauge PIV, and faster than that of a 22‐gauge PIV. The addition of adjuncts slowed flow rate. Needleless connectors had the greatest impact, reducing flow by 75% for the blood infusion set. Packed red blood cells had a viscosity 4.5 times that of normal saline and thereby reduced flow. CONCLUSION Catheter and tubing choice, adjuncts, and fluid viscosity influence flow rates. Our results will help inform adequate vascular access planning in the perioperative environment.
Intravenous infusion, whether used continuously or intermittently, is a common feature in healthcare, although not without risk. Various medical devices can be used to administer the infusion, sometimes simultaneously, of several active substances . These devices, because of their characteristics, may generate more or less significant variations in drug mass flow rate, which is the amount of drug delivered per unit of time to the patient. The first part of this work on these medical devices focuses on studying standard requirements and norms, especially definitions, as well as trial methods and expected conformity thresholds. The main elements of physiology and fluid mechanics are also addressed to offer a better grasp of the problems involved. This study is complemented by analyses of published data on the impact of medical devices on drug mass flow rate when delivered intravenously. A systematic review of publications was made, covering in vitro or in vivo studies related to the topic, targeting more particularly any infusion device likely to alter the flow or concentration of the infused drug. The first experimental in vitro work involves the simultaneous infusion of three drugs using a single infusion device with several access points. The three drugs were infused by syringe pump and a hydration solution by gravity. The purpose of this study was to assess the impact of certain features (residual volume and check valve) of two infusion devices (the former with very low residual volume and a check valve and the latter with a high residual volume and no check valve) on the mass flow of three active ingredients. Simultaneous quantification of three active ingredients in solution (isosorbide dinitrate, midazolam and norepinephrine) made it necessary to develop a multivariate method on UV spectrum (partial least square regression (PLS)). This technique meant that the three drugs could be dosed continuously (1 dose per second) at the catheter egress. The method was validated for concentration scales of 5-60, 10-80 and from 2.5 to 20 µg/ml for isosorbide dinitrate, midazolam and noradrenaline in binary mixtures and 6.67 to 30, 0.83 to 7.5 and 1.67 to 23.33 µg/ml for the same products, in ternary mixtures. The perfecting of the model made it possible to maintain the spectral region between 220 and 300 nm with an optimal Q2cum index. The recovery study, performed on prediction sets containing eight different ternary mixtures of isosorbide dinitrate, midazolam and noradrenalin, yielded recovery values ranging from 99.5 to 101% of the theoretic values. The main parameters assessed in this study were 1) the evolution of mass flow rate for the three drugs, 2) the value of the plateau mass flow rate, and 3) flow change efficiency (FCE).. FCE is obtained by dividing the area under the curve of the experimental mass flow in relation to time by the area under the curve of the expected mass flow in relation to time. This parameter was calculated at each 5-minute interval after the start of infusion. Infusion systems with reduced residual volume provided significantly better FCE (53.0 ° 15.4% with very low residual volume after 5 minutes' infusion compared to 5.6 ° 8.2% with high residual volume), regardless of any changes in flow conditions. A nonlinear relationship was established between residual volume, time since the onset of infusion and FCE. [...]
The flow of crystalloids through peripheral intravenous catheters of the same size, obtained from different manufacturers, varies significantly. Because industry standards do not exist, the amount of variation between peripheral intravenous Teflon(R) catheters from various manufacturers was measured. An electron microscope, dial calipers, and an eye loupe were used to inspect the catheters, revealing marked deviations from the labeled sizes, and significant differences between the products of various manufacturers. The outside diameters, purportedly the site of measurement for labeling, varied as much as 8% in 14g, 13% in 16g, 10% in 18g, and 27% in 20g catheters. The difference between maximum internal diameters also varied widely. Because it is vital, especially in hypovolemic resuscitations, to know the flow capabilities of intravenous catheters, industry-wide standards must be implemented and followed. However, the limited number of test samples measured in this study would suggest a larger study prior to using these data to formulate national standards. (C)1987Aspen Publishers, Inc.
Objective: Despite now being rarely used in the prehospital and emergency department arena because of their excessive length and low inner diameter, narrow-bore central venous catheters (CVC) are sometime used to perform fluid resuscitation using a rapid infusion pump to enhance delivered flow. In this bench study, we tested the hypothesis that the delivered flow rate downstream from the catheter connected to a rapid infusion pump would be significantly lower than the preset flow rate, and this difference would be affected by the catheter size. Materials and methods: Eight units of each type of catheter [two 15 and 20 cm narrow-bore CVC and three 14, 16 and 18 G peripheral venous catheters (PVC)] were connected to a rapid infusion device and were tested with physiological saline. Measurements were repeated using glycerol solution with a viscosity similar to that of packed red blood cells. Infusion pump flow rates were preset to 100, 200, 300 and 400 ml/min. Flow rates were measured downstream from catheters, each connected to a rapid infusion device. Results: The downstream flow rate remained lower than the preset flow rate except with the 14 and the 16 G PVC at 100 ml/min (P<0.001). The type of catheter significantly impacted the flow rates measured with physiological saline (F4,105=1008.83, P<0.001) and glycerol solution (F4,105=1843.46, P<0.001). Conclusion: Using a rapid infusion device, the delivered flow rate was lower than the preset flow rate. Even PVCs are better than narrow-bore CVC, neither is the most suitable cannula for patients requiring massive resuscitation.
It is known that a successful outcome after injury requires haemostasis and replacement of intra- and extracellular fluid losses. In situations of controlled haemorrhage rapid replacement of these fluid losses is likely to be associated with the least morbidity. When considering uncontrolled haemorrhage, however, there is good evidence that effective resuscitative devices and strategies have proven to be associated with a worse outcome when used initially than when their use follows surgical control of bleeding. Despite newer developments in resuscitative technique, surgeons must continue to be involved in the early management of the severely injured so that they are in the best position to employ their skills and provide surgical haemostasis when and where it is required. The 'end' therefore in resuscitation of the injured is a normovolaemic, normotensive patient who is physiologically stable and able to have definitive management of his/her anatomic injuries. The 'means' are good prehospital care, accurate initial assessment and resuscitation that employs temporary and definitive haemostasis combined with adequate volumes of appropriately chosen and delivered resuscitation fluid.
Large animal species in states of shock can require particularly high flow rates for volume resuscitation and the ability to deliver adequate volumes rapidly may be a rate-limiting step. The objective of this study was to determine the maximum flow rates of common combinations of IV catheter, extension set, and fluid administration sets. University veterinary teaching hospital. In vitro experimental study. Maximum flow rates were measured using combinations of 4 IV catheters (3 14-Ga and a single 10-Ga), 2 IV catheter extension sets (small bore and large bore), and 2 types of fluid administration sets (standard 2-lead large animal coiled IV set and nonpressurized 4-lead arthroscopic irrigation set). The catheter, extension sets, and administration sets were arranged in 16 configurations, and flow rates measured in triplicate using tap water flowing into an open receptacle. Flow rates ranged from 7.4 L/h with an over-the-wire 14-Ga catheter, small-bore extension, and coil set, to 51.2 L/h using a 10-Ga catheter, no extension, and arthroscopic irrigation set. There was an increase of 1.3–8.9% in flow rates between the large- versus small-bore extension sets. Crystalloid delivery in vivo to an adult horse was 21% slower (9.1 L/h versus 11.5 L/h) than the corresponding in vitro measurement. Extremely high flow rates can be achieved in vitro using large-bore catheters and delivery systems, although the clinical necessity for rates >50 L/h has not been determined. The use of large-bore extension sets resulted in only a minimal increase in flow rate.
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One of the clinically significant rate-limiting components in even the fastest of intravenous (IV) fluid systems is the tubing connecting the IV catheter to the IV solution container. We evaluated the effect large-bore tubing has on reducing this limitation on fluid flow, measuring gravity and pressurized flow in standard and large-bore tubing alone and when each was connected to an 8 French and 12-,14- and two types of 16-gauge catheters. When combined with an 8 French catheter, large-bore tubing produces a 126% increase in flow under gravity and a 90% increase under pressure. The improvement with the large tubing was less significant as the catheter size decreased. Studies in normovolemic adult volunteers achieved similar results. Large-bore blood tubing and large-bore catheters should be used in all situations where the need for rapid fluid replacement is contemplated.
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External pressure devices are often utilized to increase the flow rates of IV fluids in exsanguinating patients. However, increasing the flow rate by this method also increases the rate at which IV bags need changing. Time is lost and valuable personnel are preoccupied in maintaining the numerous hand-pumped external pressure devices and IV bags. A systematic evaluation comparing the hand-pumped device with a new, pneumatic external pressure device (Infusor-1, Medical Innovations, Inc., Phoenix, AZ) is presented. A new multiunit configuration (Infusor-Rack) for the pneumatic device is also described. We found a significant decrease in IV bag take-down/setup time with the new pneumatic pressure device. This system is faster, more reliable, and easier to use than the standard hand-pumped pressure bag and should be viewed as a practical improvement in the fluid delivery system.
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The ability to replace fluids rapidly is frequently the limiting factor in the survivability of trauma patients. We describe a fluid infusion system that provides approximately a fourfold increase in flow rates over currently available percutaneous systems. It incorporates a 14 French (4.5-mm internal diameter) catheter introduced into a central vein by the Seldinger technique, and a manifold that allows fluid from five separate IV bags to flow into the patient through one line. In vitro tests demonstrated a gravity flow rate of more than 850 mL/min normal saline and a flow rate under pressure of more than 2.0 L/min. Packed red blood cells diluted to 42% hematocrit flowed at 1,725 mL/min under pressure. In vivo testing in dogs demonstrated a maximum gravity flow rate of approximately 650 mL/min, and a pressurized flow rate of more than 1,600 mL/min normal saline. No unusual sequelae of large-bore catheterization were detected.
An in vitro study was conducted to determine the maximum flow rates that can be obtained with commercially available intravenous (IV) catheters, when infusion pressure and IV tubing size are modified. Standard tubing (3.2 mm ID) and two sizes of experimental large-bore tubing (5.0 mm and 6.4 mm ID) were tested with tap water and diluted packed cells (hematocrit 45) at 600 mm Hg, 300 mm Hg, and gravity flow infusion pressure. The maximum flow rate obtained was 3,158 ml/min for tap water and 3,000 ml/min for diluted packed cells. The increases in flow rates from gravity to 300 mm Hg and from gravity to 600 mm Hg are significant (P less than 0.05) and provide up to 197% and 341% increases, respectively, for all catheter/tubing combinations tested. Large-bore tubing is most effective when used in conjunction with large-bore catheters. For the 8.5 French catheter, a change from standard (3.2 mm ID) to large-bore (6.4 mm ID) tubing resulted in a statistically significant (P less than 0.05) increase in flow rate of more than 200% regardless of infusion pressure.
Catheter introducer sets developed for placement of Swan-Ganz catheters are useful as temporary large-diameter lines in hypovolemic patients. The internal diameters of 8 F introducers exceed the diameter of standard intravenous tubing. We compared an 8 F introducer to other catheters and found the introducer had a significantly faster flow rate than did a 14-gauge cannula (P less than .05). Introducers were placed successfully, without any serious complications, in 42 of 47 severely ill patients. Because catheter introducers may be inserted percutaneously into any large vein above or below the diaphragm, they are ideal for rapid fluid resuscitation.
The achievement of a very rapid fluid infusion rate may be critical in the resuscitation of the patient in hypovolemic shock. We studied flow rates of crystalloid and whole blood through various intravenous catheters and tubing systems. The 10-gauge Angiocath and the 8 Fr pulmonary artery introducer catheter provide flow rates equivalent to intravenous tubing (3.2 mm I.D.) inserted directly into the vein. Substantially higher flow rates can be achieved with the use of large-bore intravenous tubing (5.0 mm I.D.) connected to these catheters in place of standard intravenous tubing, allowing the infusion of 1,200-1,400 cc/minute of crystalloid and whole blood into the patient in hypovolemic shock through one intravenous catheter. Clinical trials with larger bore intravenous tubing are probably indicated.
The use of wire-guided catheters is a major technical advance for emergency physicians. The technique is simple, safe, and efficient, and allows tremendous flexibility in usage.
Catheter introducers for rapid fluid resuscitation.
  • Haynes B
  • Carr F
  • Neimann JT
Haynes B, Carr F, Neimann JT. Catheter introducers for rapid fluid resuscitation.
Effects of high pressure and large-bore tubing on IV flow rates
  • Mateer