Technical limitations in the rapid infusion of intravenous fluids

We compared fluid delivery, both in vitro and in vivo, using various combinations of fluid sets and intravenous catheters. Administration sets were a minidrip, a maxidrip, and a blood infusion set. The catheters included 14-, 16-, 18-, and 20-gauge short catheters, 16- and 19-gauge long catheters, and an 8 French catheter introducer for flow-directed pulmonary arterial lines. Blood infusion tubing alone delivered fluid at 3.12 +/- .07 mL/second, significantly faster than either the maxidrip (2.59 +/- .06, P less than .01) or the minidrip (0.56 +/- .02, P less than .001). The 8 French introducer provided no additional resistance to the flow of the maxidrip or blood infusion set when used in combination with an anesthesia extension. All the other catheters slowed flow significantly. Percutaneous insertion of an 8 French catheter introducer connected to blood administration tubing allows for rapid delivery of fluids and for subsequent insertion of a Swan-Ganz catheter, which is often necessary in critically ill patients.