The influence of nitroglycerin and prostaglandin E1 on dynamic cerebral autoregulation in adult patients during propofol and fentanyl anaesthesia.

Abstract

We investigated dynamic cerebral autoregulation in 24 normocapnic adult patients during propofol and fentanyl anaesthesia. Hypotension was induced, to a mean arterial pressure (MAP) of 60-65 mmHg, using nitroglycerin or prostaglandin E1. Time-averaged mean cerebral blood flow velocity in the right middle cerebral artery was measured continuously using transcranial Doppler sonography. Dynamic autoregulatory response was activated by a sudden decrease in MAP following release of bilateral thigh cuffs (thigh cuff test) and evaluated as a dynamic rate of autoregulation (dRoR in % x s(-1)). The cuff test was repeated to obtain two values of dRoR during baseline and during induced hypotension; the data were then averaged. The mean value of dRoR during baseline and during induced hypotension was 14.2 (2.9) and 14.2 (1.6) % x s(-1), respectively, in the nitroglycerin group, and 14.6 (2.6) and 14.4 (2.4) % x s(-1), in the prostaglandin E1 group. We were unable to demonstrate significant between- or within-group differences in dRoR. Thus, we conclude that nitroglycerin and prostaglandin E1 do not attenuate dynamic cerebral autoregulation.