Shock and resuscitation. III. Accurate refractometric COP determinations in hypovolemia treated with HALFD

In 38 critically burned patients with symptomatic hypovolemia being treated by intravenous fluids, the accuracy of colloid oncotic pressure (COP) calculated from the refractometrically-determined serum total protein (TPRI) was compared with COP values determined by a commercially-available clinical oncometer. Sera were obtained randomly from seven patients receiving Ringer's lactate solution, five receiving a hypertonic solution (240 mOsm Na+) and 26 receiving a hypertonic solution containing albumin (12.5 gm/liter, HALFD method). There was poor correlation between COP measure and that calculated from RI in patients receiving colloid-free fluid, but high correlation (r = 0.925) in patients receiving HALFD. There was high correlation (r = 0.951) between measured COP and values calculated from TPRI in patients receiving hypertonic fluid, colloid containing hypertonic fluid, or no fluid:COP = 4.08 (TPRI)--4.61.