ABSTRACT
Sodium nitroprusside given by intravenous drip has been used to control hypertensive crises since 1929. Its evanescent action makes it suitable for controlled hypotension during general anesthesia with enflurane. The patients (n=10) were all undergoing Cotrel-Dubousset instrumentation for the operative treatment of scoliosis or spinal stenosis. Hemodynamic variables were obtained during administration of sodium nitroprusside. Mean arterial pressure was decreased to 50-60mmHg, while cardiac output, central venous pressure, systemic vascular resistance showed only minor changes. The average dosage of sodium nitroprusside (ug/kg/ min), plotted against age, showed a significant correlation (p<0.05, r= -0.63). The amonut of whole blood transfused during operation was 5.7+/-2.2 units (mean+/-SD) and postoperative hemoglobin and hematocrit (11.19+/-1.21g/dl, 33.49+/-3.79%, respectively, mean+/-SD) were singificantly lowered than preoperative hemoglobin and hematocrit (12.94+/-1.78g/dl, 37.22+/-4.88%, respectively, mean+/-SD) (hemoglobin: p<0.004, hematoorit: p<0.006).