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.
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).
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.