Cardiac and microcirculatory effects of different doses of prostaglandin E1 in man

A cumulative dose response to intravenous PGE1 was established in 12 healthy volunteers. Systolic time intervals, including pre-ejection period (PEP), the ventricular ejection time (VET) and the RR-interval, were continuously determined, and transcutaneous oxygen pressure (tcpO2) was recorded. RR-intervals fell in a dose dependent manner, reaching a significantly lower level at 128 ng.kg-1.min-1 of PGE1 (basal value 842 ms falling to 756 ms). PEP decreased from 89 ms to 74 ms and the ratio PEP/VET decreased from 35% to 30%, indicating increased myocardial contractility. The maximal increase in tcpO2 was 125% on the calf and 60% on the foot. The peak tcpO2 was observed at an infusion rate of 16 ng.kg-1.min-1 PGE1. A decline in tcpO2 was seen at infusion rates greater than 64 ng.kg-1.min-1 PGE1 indicating a decrease in skin perfusion. The results indicate that the effects of intravenous PGE1 on skin perfusion occur at a lower threshold than the increase in myocardial contractility. A maximal increase in skin perfusion can be achieved with doses of PGE1 devoid of systemic haemodynamic effects.