The cardiorespiratory effects of perfluorochemicals on acute carbon monoxide poisoning in the pregnant ewe

Abstract

Studies in nonpregnant animal models of carbon monoxide poisoning have demonstrated the protective effect of perfluorochemicals. Anesthetized pregnant ewes were exposed to carbon monoxide. After symptoms of toxicity were demonstrated, group 1 animals were respired with room air. Group 2 animals respired room air and were given intravenous perfluorochemicals. Group 3 animals were administered 100% oxygen. Group 4 animals were given intravenous perfluorochemicals and respired 100% oxygen. In all ewes exposure to carbon monoxide resulted in increased cardiac output, heart rate, and carboxyhemoglobin level without a significant change in arterial oxygen tension. After carbon monoxide exposure, there was no significant difference in the carboxyhemoglobin to oxyhemoglobin conversion between groups 1 and 2 although the conversion rates were more rapid in groups 3 and 4. Fetal oxygenation was improved in groups 3 and 4. All fetal lambs exhibited a progressive increase in carboxyhemoglobin and a decrease in venous pH regardless of the maternal postexposure treatment. There was no significant increase in the fetal venous oxygen content of group 4 as compared with that of group 3, suggesting that the adjunctive administration of limited quantities of perfluorochemicals to the mother offers no apparent advantage over 100% oxygen alone for acute fetal resuscitation.