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Combined effect of catheter and tubing size on fluid flow

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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
KENNETH V. ISERSON, MD, ELIZABETH CRISS, RN
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-
vices.6
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,
1985,
Address reprint requests to Dr. Iserson.
Key Words: Catheter, flow rate, intravenous, rapid fluid resusci-
tation, tubing.
238
MATERIALS AND METHODS
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-
sion.
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-
ISERSON AND CRISS n CATHETER AND TUBING SIZE
TABLE 1. Mean Time (minutes:seconds) for Two Fluid Systems
Pump-up/Drain Take-down/
(1st liter) Set-up
(min:sec) (mln:sec)
Pump-up/Drain
(2nd liter)
(mmsec)
Total Time
(mln.sec)
Flow Rate
(mlisec)
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.
RESULTS
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.
DISCUSSION
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.
Viscosity’
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
239
AMERICAN JOURNAL OF EMERGENCY MEDICINE n Volume 4, Number 3 n May 1986
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-
suscitation.
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1. Dailey R. Use of wire-guided (Seldinger-type) catheters in the
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2. Haynes B, Carr F, Neimann JT. Catheter introducers for rapid
fluid resuscitation. Ann Emerg Med 1983;10:606-609,
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ology. Ann Emerg Med 1984;2:97-100.
4. Millikan J. Cain T, Hansbrough J. Rapid volume replacement
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5. lserson K, Reeter AK, Criss E. Comparison of flow rates for
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6. lserson K, Reeter A, Wood W, et al. Pressurization of IV bags:
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1980:987.
240
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... 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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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.
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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.
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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.
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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.
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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