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Choice of Catheter Size for Infants in Continuous Renal Replacement Therapy: Bigger Is Not Always Better
Francesco Garzotto1, Marta Zaccaria2, Enrico Vidal3
1Department of Nephrology, Dialysis and Transplantation, San Bortolo Hospital, Viale Ferdinando Rodolfi 37, Vicenza, Italy.
Insights
This study investigated central vascular catheter performance in infant renal replacement therapy. Optimal rheologic performance was observed when catheter and pump sizes were matched, despite a slight increase in hemolysis.
Area of Science:
- Pediatric Nephrology
- Biomedical Engineering
- Extracorporeal Circulation
Background:
- Renal replacement therapy (RRT) is crucial for infants with severe renal dysfunction.
- Early RRT initiation may prevent acute kidney injury complications.
- Effective RRT in infants requires adequate vascular access, but catheter-device interactions are understudied.
Purpose of the Study:
- To characterize the operating conditions and performance of 4F, 5F, and 7F central vascular catheters.
- To evaluate catheter performance with adult and pediatric extracorporeal blood circulation models.
- To describe the rheologic performance of different vascular access sizes with RRT models.
Main Methods:
- In vitro tests using simulated extracorporeal circuit models for pediatric and neonatal RRT.
- Experimental extracorporeal circulation circuit tests with two-roller (adult) and three-roller (pediatric) pumps.
- Pressure-flow measurements and hemolysis estimation.
Main Results:
- Maximal blood flows of 13 mL/min (4F) and 29 mL/min (5F) achieved with a small pump within safe pressures.
- Maximal flows of 10 mL/min (4F) and 20 mL/min (5F) with an adult pump.
- Higher hemolysis observed with the three-roller (pediatric) pump, though likely not clinically relevant.
Conclusions:
- Small central vascular catheters show optimal rheologic performance when RRT device pumps are size-proportionate.
- Matched catheter and pump sizes facilitate effective RRT with higher blood flows.
- Increased hemolysis risk is associated with size-matched systems but may be clinically insignificant.
Objectives:
Renal replacement therapy in infants and small children is the treatment of choice for severe oligoanuric renal dysfunction, with an increasing consensus that early initiation might contribute to preventing acute kidney injury complications. Safer renal replacement therapy devices specifically designed for neonates may contribute to ameliorating outcomes and increasing chances of survival. One of the crucial factors to achieve an effective renal replacement therapy in small infants is adequate vascular access. The interaction of small size central vascular catheters with renal replacement therapy devices has never been investigated. The aim of this study was to characterize both the operating conditions and performance of three different central vascular catheters sizes (4F, 5F, and 7F) connected to two different extracorporeal blood circulation models (adult and pediatric). The rheologic performance of each vascular access size in combination with the adult and pediatric renal replacement therapy models was described.
Design:
Series of experimental extracorporeal circulation circuit tests were conducted with different setups. A two-roller pump was used to simulate a standard adult dialysis machine, whereas a small three-roller pump served as pediatric renal replacement therapy device.
Setting:
A pressure-flow setup aimed to collect pressure and flow values under different test conditions. A second experiment focused on hemolysis estimation induced by the extracorporeal system. Hemolysis exclusively induced by the 4F catheter was also evaluated. Finally, our data were applied to estimate the optimal catheter size theoretically capable of delivering adequate doses basing on anthropometric data (patient weight and cannulation site) in absence of direct ultrasound vessel measurement.
Subjects:
In vitro tests conducted on simulated extracorporeal circuit models of continuous pediatric and neonatal renal replacement therapy.
Interventions:
None.
Measurements And Main Results:
When 4F and 5F catheters are used, maximal blood flows within safe circuit pressures can be set at the values of 13 and 29 mL/min, respectively, when a small pump is used. Differently, when using adult roller pumps, only maximal flows of 10 and 20 mL/min are reached. However, hemolysis is higher when using a three-roller pump compared with the two-roller. The clinical impact of this increased hemolytic burden is likely not relevant.
Conclusions:
Small size central vascular catheters display optimal rheologic performances in terms of pressures and flows particularly when the renal replacement therapy device is equipped with pumps proportional to central vascular catheters sizes, and even when relatively high blood flows are set. This is achieved at the risk of a higher hemolysis rate.
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