Cerebral oxygenation during prostaglandin E1 induced hypotension

Purpose: To evaluate the cerebral oxygenation effects of hypotension induced by prostaglandin E-1(PGE(1)) during fentanyl-oxygen anaesthesia. Methods: Ten patients who underwent elective cardiac surgery received infusion of PGE(1). After measuring the baseline arterial, mixed venous and internal jugular vein blood gases, systemic haemodynamics, and regional cerebral oxygen saturation (rSO(2)) estimated by INVOS 3100(R), PGE(1) was continuously infused at 0.25-0.65 mu g.kg(-1).min(-1) (mean dosage: 410 +/- 41.4 mg.kg(-1).min(-1)) intravenously. Ten, 20 and 30 minutes after the start of drug infusions, blood gases described above were obtained simultaneously with the measurement of systemic haemodynamics and rSO(2). Thirty minutes from the start of drug infusions, administration of PGE(1) was stopped. The same parameters were measured again 10, 30 minutes after the stop of drug infusion. Results: PGE(1) decreased mean arterial pressure (MAP) to approximately 70% of the baseline value (P < 0.05). PGE(1) increased mixed venous saturation, but in contrast did not effect internal jugular pressure, internal jugular oxygen saturation and rSO(2). Conclusions: These results suggest that PGE(1) is a suitable drug for induced hypotension because flow/metabolism coupling of brain and regional cerebral oxygenation were well maintained during hypotension.