Background: Despite the widespread use of nitroglycerine, little is known of its cerebral haemodynamic effects. The present study was undertaken to evaluate the effects of nitroglycerine on cerebral circulation and cognitive function in normal volunteers.
Design: Twelve healthy male volunteers (age 25 +/- 3 years; mean +/- SD) received continuous intravenous infusions of nitroglycerine at 1 mg h-1 and 2 mg h-1 rates as well as placebo (0.9% saline) under randomized, double-blind cross-over conditions on three different occasions. A 10-min quantitative EEG (qEEG) was recorded before, during and repeatedly after infusion. Blood flow velocity in the left arteria cerebri media (MCA) was measured simultaneously by means of transcranial Doppler sonography. Cognitive performance was assessed with a computerized test battery.
Results: Administration of nitroglycerine caused a significant reduction of mean blood flow velocity in the left MCA. In parallel a significant increase of absolute power density < 4 Hz was noted. The latter effect was dose dependent. Cognitive functions, such as attention and memory, were not altered.
Conclusions: The decrease in cerebral blood flow velocity in the left MCA may be due to vasodilatation and/or reduction in perfusion. The concomitant increase of slow wave power in the qEEG may indicate an impairment of brain function.