Effects of nicardipine-induced hypotension on splanchnic perfusion in patient undergoing meningioma resection / 中华麻醉学杂志

ABSTRACT

Objective Controlled hypotension induced by different drugs may have different effects on splanchnic perfusion. The purpose of this study was to assess the effects of nicardipine- induced hypotension on splanchnic perfusion. Methods Twenty-three ASA Ⅰ-Ⅱ patients (14 male, 9 female) aged 21-60 yr undergoing meningioma resection were studied. The patients were premedicated with ranitidine 150 mg per os and atropine 0.5 mg i.m. Anesthesia was induced with propofol 1.5-2.0 mg?kg-1 , fentany1 2.0?g?kg-1 and vecuronium 0.1 mg? kg-1 and maintained with isoflurane inhalation and intermittent i. v. boluses of fentanyl and vecuronium. The patients were mechanically ventilated after tracheal intubation and PETCO2 was maintained at 33-35 mm Hg. Nicardipine-induced hypotension started from opening of mininges to the resection of tumor. 0.01% nicardipine infusion was started at 30 ml?h-1 and adjusted to reduce systolic blood pressure by 30% of the baseline or MAP to≥60 mm Hg. The adequacy of splanchnic perfusion was defined by gastric intramucosal CO2 tension (PgCO2), the intramucosal pH (pHi) and the difference between intramucosal and arterial PCO2(PCO2 gap) and was assessed before induction of anesthesia, the 1st, 2nd and 3rd hour during controlled hypotension and 1, 2 hour after termination of controlled hypotension. Results The MAP was maintained at about 62 mm Hg during controlled hypotension. The heart rate was stable. Hct was significantly decreased at 1st, 2nd and 3rd hour of hypotension compared with baseline but the mean Hct was greater than 30% . The intramucosal pH decreased slightly with no statistical significance and pHa, PaCO2 , PgCO2 and PCO2 gap were almost unchanged during controlled hypotension compared with the baseline values. Conclusion Nicardipine-induced hypotension is safe when MAP is maintained at≥60 mm Hg and has no adverse effects on splanchnic perfusion.