BLOOD-VOLUME DETERMINATION USING HYDROXYETHYL STARCH - A RAPID AND SIMPLE INTRAVENOUS-INJECTION METHOD

Objective: To develop and evaluate a new method for blood volume measu rements using hydroxyethyl starch as a dilution marker. Design: Labora tory and clinical investigation. Setting: Neurosurgical operating room s and anesthesiological laboratories of a university hospital, Patient s: Twelve patients who underwent a neurosurgical operation. interventi ons: Anesthesia and operations were carried out by physicians who were not involved in the study. In addition, blood samples were drawn from 50 volunteers. Measurements and Main Results: Blood volume measuremen ts by the hydroxyethyl starch method were validated in vivo by com par ison with a conventional carbon monoxide technique. Patients were intr avenously injected with hydroxyethyl starch (100 mt) and received simu ltaneously an injection of carbon monoxide (50 mt) into a closed-circu it ventilation system. Brood samples obtained before and 5 mins after injection were analyzed for carboxyhemoglobin and glucose plasma conce ntrations after acidic hydrolysis of hydroxyethyl starch, Blood volume was calculated from the difference between glucose concentrations mea sured after hydrolysis in the plasma, before and after the addition of hydroxyethyl starch. In vitro, the hydroxyethyl starch method had an error and a precision of similar to 2%. In vivo, simultaneous measurem ents of blood volume using hydroxyethyl starch and carbon monoxide dem onstrated a high correlation (r(2) = .96, p < .001)between these meth ods. The mean difference between the two methods relative to their ave rage value was 1.0 +/- 3.5%; the bias was 52.3 mt, and the 95% confide nce interval was -64.0 to +168.7 mL. Conclusions: Blood volume determi nation by the hydroxyethyl starch method is accurate and rapid and may enhance perioperative monitoring of fluid and blood therapy.