Hypertonic saline prehydration in patients undergoing transurethral resection of the prostate under spinal anaesthesia

Thirty-three patients undergoing elective transurethral resection of the prostate were allocated randomly to receive either 0.9% isotonic saline 7 ml kg^-1 (16 patients), or 3% hypertonic saline 7 ml kg^-1 (17 patients) as a preload before spinal anaesthesia. After spinal anaesthesia, the incidence of systolic arterial pressure < 75% of control value was greater in the normal saline group than in the hypertonic saline group. Also, the mean dose of phenylephrine required to maintain arterial pressure > 75% of the baseline value was significantly greater in the normal saline group than in the hypertonic saline group.