Effects of Crystalloid Administration Before Spinal Block On Hypotention in Elderly

One of the anesthetic techniques with a lot of clinical benefits is spinal block that is produced by injection of local anesthetic solution into the subarachnoid space. This procedure caused 15-18% reduction in peripheral vascular resistance. Decreased blood pressure as a complication of spinal block may be seen in one third of cases. Intravenous fluids before induction is recommended for prevention of this event. There are contradictory studies in this Issue. Propose of this study was determination the effects of Crystalloid administration as a prehydration before operation on decrease of blood pressure. In this randomized clinical trial, double- blind study we selected 112 patients 60-90 years old who did not have any history of hypertension and CHF and antihypertensive medication and were candidate for elective lower abdomen operation. After taking informed consent, patients divided into 2 groups randomly. 500cc Ringer was infused 20 minutes before spinal anesthesia for the first group, second group received no intervention. Blood pressure after 5th, 10th, 15th, 20th minutes was reported. Blood pressure lower than 90-mmhg or more than %30 lower than baseline considered as decreased blood pressure and treated with 5mg Ephedrine. Data was analyzed with SPSS/9 software. We used Chi square and student T-Test, P<0.05 was considered meaningful. There was no significant difference between sex, age, weight and height with level of anesthesia in patients. The rate of decreased blood pressure in 5th minute in first group was 34(60.7%) and in second group was 27(48.2%) which was no significant difference. Ephedrine administration was 34mg in first and 27mg in second group. In both groups 5 persons (8.9%) had nausea and vomiting after spinal anesthesia. In this study Crystalloid administration as prehydration did not reduce occurrence of hypotention. This procedure is not useful for aging people and more studies for prevention of this complication is recommend.