Epidural Multiorifice Catheters Function as Single-Orifice Catheters: An In Vitro Study

In Brief In an in vitro study, we determined the flow rates required to use selective orifices of multiorifice catheters. Saline was infused at rates between 1 and 360 mL/h through Portex and Braun 20-gauge multiorifice catheters using Baxter, Abbott Laboratories, and Alaris infusion pumps. The numbers of orifices used via infusion and manual injection, and the pressure within the catheter during continuous infusion, were recorded. Infusion rates <80 mL/h used one orifice, between 100 and 280 mL/h used two orifices, and >300 mL/h used three orifices. Catheter pressures with Braun catheters were 40% greater than with Portex catheters. Manual injections by all 12 residents used all three orifices. Twenty-gauge multiorifice catheters function as single-orifice catheters at clinically relevant infusion rates, but function as multiorifice catheters during manual boluses. IMPLICATIONS: We determined the flow rates required to use all three orifices of multiorifice catheters. Continuous infusion rates up to 80 mL/h used a single orifice; rates between 100 and 280 mL/h used two orifices; rates in excess of 300 mL/h used all three orifices. We conclude that 20-gauge multiorifice catheters function as single-orifice catheters at clinically relevant epidural infusion rates.