EFFECTS OF A PERFLUOROCARBON EMULSION FOR ENHANCED O-2 SOLUBILITY ON HEMODYNAMICS AND O-2 TRANSPORT IN DOGS

Perfluorocarbon emulsions raise blood O-2 solubility and thus augment O-2 transport, but their cardiopulmonary effects at higher doses may limit their use. We therefore examined effects of increasing doses of perfluorooctylbromide emulsion (Oxy) on 1) pulmonary gas exchange, 2) pulmonary and systemic hemodynamics, and 3) mixed venous Po-2 (P-(v over bar 2)). After hematocrit reduction to 24-26% by exchange with 5% albumin, anesthetized ventilated dogs breathing 100% O-2 were given Oxy (n = 6) or 5% albumin (n = 5) intravenously in four successive 3 ml/kg doses. After each dose, arterial and venous Po-2, Pco(2), and pH, [O-2], hematocrit, heart rate, and systemic, pulmonary arterial, and airway pressures were measured. Ventilation-perfusion relationships and cardiac output (Q(T)) were determined by the multiple inert gas method. Oxy at 12 ml/kg almost doubled blood O-2 solubility, increasing arterial [O-2] by 1.28 ml/100 ml but did not affect O-2 consumption and ventilation-perfusion relationships. Q(T) rose by 21% after 3 ml/kg, then fell with increasing doses (-18% from baseline after 12 ml/kg); O-2 delivery remained constant. Oxy at >6 ml/kg increased systemic blood pressure and systemic vascular resistance considerably. Mean pulmonary arterial pressure and pulmonary vascular resistance increased slightly. Airway pressures were unaffected. P-(V over bar o2), rose from 66 to 77 Torr (6 ml/kg), then fell to 72 Torr (12 ml/kg), in accord with theoretical predictions. In this model, Oxy 1) does not impair pulmonary gas exchange in doses up to 12 ml/kg, 2) leads to progressively higher systemic vascular resistance and fall in Q(T) at >3-6 ml/kg, possibly because of increased blood viscosity, and 3) augments P-(v over bar o2), as predicted from the increase in plasma O-2 solubility.