Article, Cardiology

Are three ports better than one? An evaluation of flow rates using all ports of a triple lumen central venous catheter in volume resuscitation

a b s t r a c t

Background: Poiseuille’s law states flow rates are directly proportional to the radius to the 4th power and indi- rectly proportional to the length of a tube. Because of this property, large bore catheters are commonly used in the resuscitation of the critically ill patient. However, there are no studies comparing simultaneous use of all three lumens of a triple lumen (TL) Central venous catheter with other catheter types. Our objective was to compare the flow rates of normal saline (NS) through various resuscitation catheters against a TL CVC using all 3 ports.

Methods: We performed a blinded prospective observational study of flow rates utilizing multiple resuscitation catheters. Each catheter type was attached to a 1 l bag of NS using standard saline tubing and mean time to infuse 1 l of normal saline was determined. Three trials each were completed with and without pressure bags.

Results: Simultaneous infusion of NS through all ports of a TL CVC demonstrated no statistically significant differ- ence compared to the following catheters: 16 ga peripheral venous catheter (PVC) and 6 Fr CVC with pressure bag. The 14 g PVC and 8.5Fr CVC had statistically significant faster flow rates than the TL CVC both with and with- out a pressure bag. The 6Fr CVC showed significantly faster flow rates than the TL CVC without a pressure bag. Conclusions: Simultaneous use of all 3 ports of a TL CVC generates flow rates comparable to many other common- ly used resuscitation catheters.

(C) 2017

Introduction

The rapid delivery of intravenous (IV)1 fluids can be essential for the resuscitation of critically ill patients. Many catheters are used in resusci- tation, with varying rates of flow. According to Poiseuille’s law, flow is directly proportional to the radius to the fourth power and inversely proportional to the length of a tube. Thus, shorter large bore catheters such as sheath introducers are often chosen to maximize rate of fluid in- fusion. Mateer et al. determined that 8 and 9 Fr sheath introducers had significantly faster in vitro flow rates of saline and blood products than large bore PVCs [1]. This was confirmed in another study that

Abbreviations: TL, triple lumen; CVC, central venous catheter; NS, normal saline; PVC, peripheral venous catheter.

? Presented at ACEP.

?? Funding: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

* Corresponding author at: Department of Emergency Medicine, Beaumont Health, 3601 W 13 Mile Road, Royal Oak, MI 48073, United States.

E-mail address: [email protected] (S. Traylor).

1 IV = intravenous

specifically compared 8 Fr sheath introducers to 14 gauge PVCs with sig- nificantly faster flow rates by the sheath introducer in critically ill pa- tients [2]. Use of these large bore catheters has become a widely accepted means of rapid volume replacement. However, other factors affect flow rates beyond catheter size alone, including type and temper- ature of fluid to be infused, kinking of catheter introducer, and type of IV tubing [3].

TL CVCs are commonly used in the resuscitation of critically ill pa- tients. TL catheters are widely available in emergency departments and have the advantage of allowing for the simultaneous infusion of blood products, medications, and IV fluids through up to three different ports. To our knowledge, no studies have evaluated IV flow rates using simulta- neous use of all three lumens of a TL CVC. Our objective was to compare the flow rates of NS through various catheters commonly used in resusci- tation against a TL CVC utilizing all three ports simultaneously.

Methods

We studied the effect of catheter size on the flow rate of normal sa- line. We selected several different catheter types including CVCs and

https://doi.org/10.1016/j.ajem.2017.09.058

0735-6757/(C) 2017

Table 1

Specifications of study catheters.

Table 3

Flow rates and time to empty by catheter type in pressure trials.

Type

Length

Gauge

Catheter type

Time 1

Flow rate (ml/min)

P-value compared w/ TLC3

Pressure injectible multi-lumen CVC

20 cm

Distal port: 16

TL- distal port

15:45

63.47

b 0.001

Medial Port: 18

TL- 2 ports

11:01

90.806

0.08

Proximal Port: 18

TL- all 3 ports

6:54

145.001

N/A

Percutaneous sheath introducer (large bore CVC)

10 cm

14.4 (6 Fr)

16 ga PVC

6:26

155.44

0.08

10 cm

11.8 (8.5 Fr)

6 Fr CVC

6:16

159.433

0.31

Angiocatheters (PVCs)

4.5 cm

14

14 ga PVC

6:02

165.746

0.008

3.0 cm

16

8.5 Fr CVC

5:16

189.673

0.02

PVCs that we have readily available in our emergency department. Type and size specifications are shown in Table 1. catheter length was mea- sured from the site of injection to the exit port. Diameter was obtained from the specifications listed on the packaging and confirmed by our measurement. Each catheter was attached to IV tubing connected to a 1 l bag of 0.9 saline at a height of 72 in. (182.88 cm). The catheter ends were fed into basins placed on the floor. The identification of the catheter types were visible on one side of a hospital bed, but obscured by the bed to the recorders on the other side. An unblinded group of ex- perimenters held the proximal end of the IV tubing for each catheter in a kinked no-flow position.

Upon instruction by a blinded time-keeper, the IV tubing was unkinked, allowing flow to begin at which point a stop watch was begun. The saline was allowed to flow until the liter bags were empty at which point the time was recorded. Time at empty was measured as the point where continuous flow in the giving set stopped which was de- termined by the blinded observers. The procedure was then repeated for a total of 3 trials. Following this, the entire experiment was repeated, but with the application of pressure bags set at 300 mm Hg to each setup. During the experiment, the pressure was maintained at 300 mm Hg. The primary endpoint was time to empty 1 l for each catheter. Because the TL CVC had multiple liter bags running simultaneously, time to 1 l was calculated from total time to empty all bags. Flow rates were deter- mined and the statistical significance was calculated via ANOVA.

Results

During our trial the mean time to infuse 1 l NS (TIME1) across all in- fusion options in our study are outlined in Table 1. Of note, it took 19:45, 12:33, and 8:44 to infuse 1 l of NS with gravity using the TL CVC with only the distal port (TLC1), TLC with 2 ports simultaneously (TLC2), and TL CVC with all 3 ports simultaneously (TLC3) respectively. Further- more, it took 15:45, 11:01, 6:54 to infuse 1 l of NS with pressure bags using TLC1, TLC2, and TLC3, respectively. The TLC3 demonstrated no sta- tistically significant difference compared to the following catheters: PVC (p-value 0.07 with gravity, 0.08 with pressure), TLC2 with the pressure bag (p-value 0.08), and 6 Fr CVC with pressure bag (p-value 0.311). The

8.5 Fr CVC had significantly faster flow rates in both gravity (TIME1 6:12, p-value 0.007) and pressure (TIME1 5:16, p-value 0.02) trials. The 14 ga PVC had TIME1 of 7:00 (p-value 0.001) in the gravity trials (Table 2) and 6:02 (p-value 0.008) in the pressure trials (Table 3).

Discussion

Our results show that simultaneous use of all 3 ports of a triple lumen catheter significantly improved the ability of the TL CVC to func- tion as a resuscitation catheter and generatED flow rates comparable to other commonly used resuscitation catheters. It is also notable that al- though the 8.5 Fr CVC demonstrated statistically significant higher flow rates than the TL CVC, the time to infuse 1 l was b 3 min faster in the gravity trial and b 2 min faster in the pressure bag trial compared to the TLC3. This is of questionable clinical significance, although it would require in vivo studies to determine if there were measurable dif- ferences in clinical outcomes.

The triple lumen catheter also provides increased versatility com- pared to large bore single lumen catheters. Many critically ill patients have difficult access and require multiple medications that vary in their compatibility. Triple lumen catheters have the benefit of both mul- tiple ports in addition to allowing comparable flow rates to other catheters.

As catheters vary in cost and ease of insertion, we believe these re- sults will have practical importance in the delivery of IV fluids during resuscitation.

Further studies will be necessary to compare the flow rates in Live patients as well as those looking at other fluids, including blood prod- ucts, which are an important component of resuscitation.

Acknowledgements

No funding was provided for this project.

Conflicts of interest

The authors have no conflicts of interest to disclose.

References

  1. Mateer JR, Thompson BM, Aprahamian C, Darin JC. Rapid fluid resuscitation with cen- tral venous catheters. Ann Emerg Med 1983;12(3):149-52. https://doi.org/10.1016/ s0196-0644(83)80556-3.
  2. Haynes BE, Carr FJ, Niemann JT. Catheter introducers for rapid fluid resuscitation. Ann Emerg Med 1983;12(10):606-9. https://doi.org/10.1016/s0196-0644(83)80204-2.
  3. Dutky PA, Stevens SL, Maull KI. Factors affecting rapid fluid resuscitation with large- bore introducer catheters. J Trauma 1989;29(6):856-60. https://doi.org/10.1097/ 00005373-198906000-00025.

    Table 2

    Flow rates and time to empty by catheter type in gravity trials.

    Catheter type

    Time 1

    Flow rate (ml/min)

    P-value compared w/ TLC3

    TL- distal port

    19:45

    50.648

    b0.001

    TL- 2 ports

    12:33

    79.707

    b0.001

    TL- all 3 ports

    8:44

    114.405

    N/A

    16 ga PVC

    7:36

    131.675

    0.07

    6 Fr CVC

    7:26

    134.63

    0.002

    14 ga PVC

    7:00

    142.971

    0.001

    8.5 Fr CVC

    6:12

    161.435

    0.007

Leave a Reply

Your email address will not be published. Required fields are marked *