Detection of intravenous fluid extravasation using resistance measurements.

Abstract

Resistance to fluid infusion can be derived from measurements of pressure at two or more flow rates. We measured resistance in 31 patients using a pressure-monitoring infusion pump (Model 560, IVAC) by recording pressure at five flow rates (0, 50, 100, 200, and 300 mL/hr), and computing resistance as the slope of the pressure versus flow curve. Resistance was measured subcutaneously (Rtissue) and intravenously (Rvein) immediately after unsuccessful or successful IV catheter placement. In all patients, Rtissue was always greater than Rvein. The difference ranged from 23 resistance units (RU) to 4166 RU, with a mean difference of 1147 RU (p < 0.0001, Student's t-test). Unpaired analysis of the..