Prevention of postoperative hypotension following spinal anesthesia for TURP: a double-blind randomized controlled trial comparing ephedrine with placebo

Spinal hypotension (SH) is a common side effect of spinal anesthesia and may also occur after the surgical procedure. In this double-blinded, placebo-controlled, randomised clinical trial fifty patients undergoing transurethral prostatectomy under spinal anesthesia received 10 mg of ephedrine IV before being transferred from the operating table into their bed after the procedure, whereas fifty controls received saline IV. The number of per- and postoperative hypotensive episodes and vasopressor use, time delay between the administration of the study medication and the first hypotensive episode, level of spinal blockade at the start of surgery, pre- and postoperative hemoglobine and sodium concentration, cardiovascular co-morbidity and chronic medication were registered. There was no statistically significant difference in the incidence of postoperative hypotension between the two groups, but Poisson regression of the expected number of postoperative hypotensive episodes per patient showed a protective effect of ephedrine (p < 0.05). The occurence of peroperative hypotension was a risk factor for developing postoperative hypotension (p < 0.05). There was no statistically significant relation between age, level of spinal blockade, cardiovascular co-morbidity or biochemical parameters and the risk of developing per- or postoperative hypotension, except for a correlation between preoperative alpha-receptor blocking drugs and peroperative hypotension (p < 0.05). Postoperative hypotension (recorded incidence 31%) was almost as common as peroperative hypotension (recorded incidence 37%) and occurred as late as 190 minutes after the end of surgery. Ephedrine IV at the end of surgery reduced the number of postoperative hypotensive episodes per patient but did not reduce the overall incidence of postoperative SH.