Randomized controlled trial to compare the effects of nicardipine and prostaglandin E1 induced hypotension on arterial oxygen pressure in patients undergoing brain tumor resection under general anesthesia

Abstract

Objective: Arterial oxygen pressure (PaO₂) may decrease at induced hypotension during general anesthesia by nicardipine or prostaglandin E₁ (PG). The present study was performed to compare the effects of nicardipine and PG on PaO₂ during induced hypotension in general anesthesia.
Methodology: This randomized controlled non-blind study was conducted at our operating room at the University Hospital. Fifty patients aged 40 to 65 years for resection of brain tumor were enrolled in the study. During general anesthesia with isoflurane, nitrous oxide and fentanyl, when hemodynamics were stable, PG 0.05 µg/kg/min, or 0.1 µg/kg/min, or nicardipine 0.5 µg/kg/min, or 1.0 µg/kg/min was administered for two hours in 10 patients each. Another 10 patients were reserved as the control. Arterial blood pressure, heart rate, percutaneous oxygen saturation (SpO₂), end-tidal carbon dioxide pressure (EtCO₂), and arterial oxygen (PaO₂) and carbon dioxide (PaCO₂) pressures were measured until 90 min after stop of administration of PG or nicardipine. Ratio of PaO₂ and oxygen fraction (P/F ratio) was calculated.
Results: Both PG and nicardipine decreased blood pressure similarly with increase in heart rate. P/F ratio decreased only with PG.
Conclusion. The use of prostaglandin E₁ to induce hypotension during general anesthesia is associated with a decreased PaO₂, while nicardipine has no effect. This difference in effect on PaO₂ is important in selecting an agent to induce hypotension in neurosurgery.
Citation: Nishiyama T. Randomized controlled trial to compare the effects of nicardipine and prostaglandin E1 induced hypotension on arterial oxygen pressure in patients undergoing brain tumor resection under general anesthesia. Anaesth Pain & Intensive Care 2015;19(1):3-7