Urinary catheterization may not be necessary in minor surgery under spinal anesthesia with long-acting local...

This prospective study was designed to compare the incidence of urinary retention after spinal anesthesia between 0.5% hyperbaric bupivacaine and 0.5% hyperbaric tetracaine in patients who underwent minor orthopedic and general surgeries.

Eighty patients aged 18-40 were randomly assigned to receive either hyperbaric bupivacaine or tetracaine for spinal anesthesia. Intravenous fluids were administered for maintenance of basal requirement, replacement of blood loss and prevention of hypotension. The highest level of analgesia, regression time of sensory block to L5 level, length of time from spinal injection to spontaneous urinary voidance, and volume of perioperative fluid administered were recorded.

Of the 80 patients who received either hernioplasty, fistulectomy, hemorroidectomy or orthopedic surgery, two were catheterized (2.5%) because of urinary retention. They were administered less than 800 mL of fluid intraoperatively. Intraoperative blood loss was less than 100 mL in all cases. There were no statistical differences in demographic data, types of surgery, sensory blockade and perioperative fluid administration between the two groups. Although the regression time of sensory blockade with tetracaine (means +/- SD, 259.3 +/- 39.6 min) was significantly longer than that of bupivacaine (225.0 +/- 38.6 min, P < 0.01), the time elapsing from the spinal injection to the first spontaneously voiding after surgery did not show statistical difference between two groups (433.9 +/- 89.1 vs. 411.0 +/- 98.3 min, P = 0.286).

Our results show that, in younger surgical patients who did not receive large amount of fluid intraoperatively, the incidence of urinary retention was low, although prolonged sensory blockade by both long-acting local anesthetics was evident. Thus, urinary catheterization should not be a routine must for every patient undergoing minor surgery with long-acting spinal local anesthetics. From the viewpoint of financial expense, avoidance of complication and annoyance of urinary catheterization, careful observation of urinary bladder fullness in the form of lower abdominal distension, discomfort, bradycardia, or vomiting after surgery is superior to routine retention urinary catheterization just for ease with work in younger patients under-going minor surgery under long-acting spinal local anesthetics.