SPINAL ANAESTHESIA FOR CESAREAN DELIVERY; STUDY OF DIFFERENT DOSES OF IV EPHEDRINE AS PROPHYLAXIS TO PREVENT HYPOTENSION DURING

To determine the effective dose of intravenous ephedrine for the prevention of hypotension during spinal anesthesiafor cesarean delivery. Design: A randomized, double-blinded dose finding study. Place and Duration: The study was carried out in CombinedMilitary Hospital Gujranwala from March 2009 to March 2010. Methodology: Total patients were 80 full term women who were randomlyallocated into four groups and were given Ringer lactate 10 ml per kg body weight intravenously. One minute after the spinal injection, patientswere given saline control or ephedrine 0.1mg per kg body weight, 0.25mg per kg body weight, or 0.4mg per kg body weight for 30 seconds. Thestudy period started at the time of spinal injection and continued for 15 minutes. Systolic arterial pressure and heart rate were recorded at 1-minintervals. Side effects like hypotension, hypertension, tachycardia, bradycardia, nausea and vomiting were also recorded. Total rescueephedrine and total dose of used ephedrine in all groups were measured. Neonates were assessed by APGAR score. Results: There was lessincidence of hypotension in the ephedrine 0.4mg per kg body weight and 0.25 mg per kg body weight group as compared with ephedrine 0.1mgper kg body weight and the control group, 5(25%),13(65%) vs. 16(80%), 18 (90%) respectively. Systolic arterial pressure (SAP) in the first 15min after the spinal injection was statistically significant greater in the 0.4mg per kg body weight group compared with other groups (P <0.001).Reactive hypertension occurred in 9(45%) in the 0.4mg per kg group, compared with control group, 0(0%), ephedrine 0.1 mg, 1(5%) andephedrine 0.25 mg 3(15%) patients. The Heart rate in the first 15 minutes in the ephedrine 0.4mg per kg body weight and 0.25 mg per kg bodyweight group was statistically significant higher than those of ephedrine 0.1mg per kg body weight and control group (P<0.001). The incidenceof tachycardia was more in ephedrine 0.4 mg per kg body weight and 0.25 mg per kg body weight groups as compared to ephedrine 0.1mg perkg body weight and the control group, 9 (45%), 6 (30%) vs. 3 (15%), 2 (10%) respectively. There were significant decrease in total doses ofrescue ephedrine required in the ephedrine0.4mg per kg body weight group as compared to other three groups. Total doses of used ephedrinein all groups were similar. Conclusion: We conclude that although ephedrine 0.25 mg per kg body weight reduces the hypotension but thesmallest effective dose of ephedrine to reduce the incidence of hypotension significantly was 0.4mg per kg body weight.