Same sized three-way indwelling urinary catheters from various manufacturers present different irrigation and drainage properties

Abstract

Background: The three-way indwelling urinary catheter (IUC) is used for continuous bladder irrigation and is considered the cornerstone for clinical treatment of patients with macroscopic hematuria. Although there seems to be a logical relationship between catheter size and efficacy of irrigation and drainage, we often observe relevant variations in these parameters between different brands of catheters available on the market. The aim of this study was to compare the mechanical properties of different models of latex and silicone three-way catheters in an in vitro setting that resembles clinical use. Methods: Three different three-way catheters were evaluated: Gold Silicone-Coated Rusch® (Model A), 100% Silicone Rusch® (Model B) and X-Flow Coloplast® (Model C). Irrigation channel, drainage channel, and overall cross-sectional areas were all digitally measured. Irrigation and drainage channel flow rates were measured and correlated with their corresponding catheter cross-sectional area values. Results: Different catheter models of the same caliber have different internal irrigation port diameters, internal drainage port diameters and internal cuff port diameters. The Model C IUC internal irrigation port diameter is significantly larger than models A and B. When flows were evaluated, we found that in the same model, the increase in caliber of the IUC was related to an increased drainage flow, but not to an increased irrigation flow. Conclusion: Precise measurements of the internal architecture of the three-way catheter, rather than relying on the caliber itself, could assist surgeons in choosing the best product for each specific patient, while minimizing complications.

Analysis of flow rate of continuous bladder irrigation according to the height of the irrigation infusion set

“…First, when the temperature of the irrigation fluid, bladder pressure, and height of the irrigation infusion set are held constant, the flow rate increases with the increasing diameter of the indwelling catheter. These results are consistent with previous findings 2 , 11 , 16 , 23 showing a positive relationship between catheter size and flow rate, which enables the effective elimination of urine, including thrombosis in the bladder. Based on the friction-adjusted Bernoulli's equation used in this study, the flow rate of the irrigation fluid entering the bladder is directly proportional to the diameter of the indwelling catheter.…”

“…These results align with Chang et al 12 , who observe a continuous increase in flow rate up to a height of 80 cm, but differ from their report of a decrease in infusion rate beyond that height. Notably, our study revealed that when the irrigation infusion set height matched that of the bladder or was below 10 cm, the irrigation fluid refluxed from the bladder towards the catheter, which was not reported in previous studies 9 , 11 , 24 . This discrepancy can be attributed to previous studies using model bladders and setting the bladder pressure to atmospheric pressure, instead of considering the actual bladder pressure in humans, when calculating or experimenting with bladder irrigation flow rate.…”

“…Second, under the same intra-bladder pressure, size of indwelling catheter, and height of the fluid bag, the flow rate into the bladder is greater with room-temperature NS than cold saline. Most past studies 9 , 11 , 12 , 24 have calculated the flow rate during CBI using room-temperature NS. However, given that irrigation fluids at varying temperatures are used in clinical practice depending on the patient’s state, it is necessary to examine flow rates when using irrigation fluids at varying temperatures.…”

“…Normal saline (NS) at room temperature is generally used for bladder irrigation to prevent bladder spasms and water intoxication 6 , 9 , and cold saline (4 °C) may be used to reduce hemorrhage through vasoconstriction in cases of severe bladder hemorrhage 10 . CBI is generally performed using a three-lumen catheter 3 , 11 , with an 18Fr catheter for patients without severe hematuria and a 22Fr catheter for those expected to develop severe hematuria 2 .…”