Prevention of hypotension by a single 5-mg dose of ephedrine during small-dose spinal anesthesia in prehydrated cesarean delivery patients

To evaluate the effectiveness of prophylactic ephedrine for the prevention of hypotension associated with spinal anesthesia, 50 parturients undergoing cesarean delivery received either ephedrine 5 mg. or saline IV in a double -blinded fashion immediately after the induction of spinal anesthesia. Spin al anesthesia was performed with hyperbaric bupivacaine 6.6 mg combined wit h sufentanil 3.3 mu g as part of a combined spinal-epidural technique. All patients received 1000 mL of lactated Ringer's solution and 500 mL of hydro xyethyl-starch 6% before the spinal injection. Additional ephedrine boluses (5 mg) were administered IV when the systolic blood pressure or heart rate decreased by more than 30% from baseline values, when systolic blood press ure became <100 mm Hg, or when patients complained of nausea or feeling fai nt. The height of the block was equal in the groups; however, more patients in the placebo group were found to develop hypotension (58% vs 25%, P < 0. 05). Only 2 (8%) patients in the ephedrine group developed hypotension with systolic blood pressure values <90 nun Hg, whereas 10 patients (42%) in th e saline group experienced hypotension of this severity (P < 0.05). In addi tion, there was a higher incidence of nausea in the placebo-treated patient s. The total amount of ephedrine administered did not differ between groups . These findings suggest that the incidence and severity of hypotension are significantly reduced by the IV administration of a prophylactic dose of 5 mg ephedrine in patients receiving small-dose spinal anesthesia for cesare an delivery. Implications: Ephedrine is the drug most often used to correct hypotension during spinal anesthesia for cesarean delivery in healthy pati ents. A single IV dose of 5 mg decreases the occurrence and limits the seve rity of hypotension in prehydrated subjects receiving a small-dose spinal l ocal anesthetic-opioid combination.