Effects of a perfluorocarbon emulsion for enhanced O2 solubility on hemodynamics and O2 transport in dogs.

Perfluorocarbon emulsions raise blood O2 solubility and thus augment O2 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 PO2 (PVO2). After hematocrit reduction to 24-26% by exchange with 5% albumin, anesthetized ventilated dogs breathing 100% O2 were given Oxy (n = 6) or 5% albumin (n = 5) intravenously in four successive 3 ml/kg doses. After each dose, arterial and venous PO2, PCO2, and pH, [O2], hematocrit, heart rate, and systemic, pulmonary arterial, and airway pressures were measured. Ventilation-perfusion relationships and cardiac output (QT) were determined by the multiple inert gas method. Oxy at 12 ml/kg almost doubled blood O2 solubility, increasing arterial [O2] by 1.28 ml/100 ml but did not affect O2 consumption and ventilation-perfusion relationships. QT rose by 21% after 3 ml/kg, then fell with increasing doses (-18% from baseline after 12 ml/kg); O2 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. PVO2 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) dose not impair pulmonary gas exchange in doses up to 12 ml/kg, 2) leads to progressively higher systemic vascular resistance and fall in QT at > 3-6 ml/kg, possibly because of increased blood viscosity, and 3) augments PVO2, as predicted from the increase in plasma O2 solubility.