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 l imit their use. We therefore examined effects of increasing doses of p erfluorooctylbromide emulsion (Oxy) on 1) pulmonary gas exchange, 2) p ulmonary and systemic hemodynamics, and 3) mixed venous Po-2 (P-(v ove r bar 2)). After hematocrit reduction to 24-26% by exchange with 5% al bumin, 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 airw ay pressures were measured. Ventilation-perfusion relationships and ca rdiac output (Q(T)) were determined by the multiple inert gas method. Oxy at 12 ml/kg almost doubled blood O-2 solubility, increasing arteri al [O-2] by 1.28 ml/100 ml but did not affect O-2 consumption and vent ilation-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 de livery remained constant. Oxy at >6 ml/kg increased systemic blood pre ssure and systemic vascular resistance considerably. Mean pulmonary ar terial pressure and pulmonary vascular resistance increased slightly. Airway pressures were unaffected. P-(V over bar o2), rose from 66 to 7 7 Torr (6 ml/kg), then fell to 72 Torr (12 ml/kg), in accord with theo retical predictions. In this model, Oxy 1) does not impair pulmonary g as 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.