An investigation into the reduction in flow rate of intravenous fluid by antireflux valves.

We have investigated the extent to which antireflux (non-return) valves impede the maximum flow rate of crystalloid in intravenous infusion systems when administered either under gravity or with 300 mmHg added pressure. When used with a 16G cannula, a reduction in flow rate of 19-38% was consistently seen. With a 20G cannula, no significant reduction in flow was found. The valve tested that produced the least reduction in flow was the Westcott Sae-flo valve.