Flow rates of double‐lumen over‐the‐wire catheters for high‐volume fluid resuscitation in large animal species

To evaluate the maximum in vitro flow rate of 6 types of polyurethane over-the-wire double lumen catheters using both ports, for high volume fluid resuscitation in large animal species.University teaching hospital.Prospective in vitro experimental study.The flow rate of both ports of 6 polyurethane double lumen over-the-wire catheters (11 and 13-Fr, 15 and 20 cm long, elliptical and tapered tip designs) and 2 types of infusion (with or without pressure bags) were tested on a factorial scheme (6 × 2) in triplicate, using commercial isotonic crystalloid (0.9% NaCl) and synthetic colloid (6% Hydroxyethyl starch, 130/0.4).Flow rates were influenced by catheter diameter, length, tip design and presence or absence of pressure bags (P < 0.05). Mean flow rates during non-pressurized 0.9% NaCl infusion ranged from 584 mL/min (35 L/h; 11-Fr x 15 cm x tapered tip catheter) to 905 mL/min (54 L/h; 13-Fr x 15 cm x elliptical tip catheter). Mean flow rates during non-pressurized synthetic colloid infusion varied from 404 mL/min (24 L/h; 11-Fr x 15 cm x tapered tip catheter) to 724 mL/min (43 L/h; 13-Fr x 15 cm x elliptical tip catheter). Mean flow rates during pressurized infusion were 1.72 and 2.02 times greater than those obtained by gravity alone for 0.9% NaCl and synthetic colloid, respectively (P < 0.05).Highest in vitro flow rates were achieved when larger diameter, shorter and elliptical tip catheters were used during 0.9% NaCl infusion. Catheter diameter, tip design but not length influenced the flow rate during synthetic colloid infusion. The use of pressure bags significantly increased the flow rate of all catheters, for both solutions.