Urinary retention after spinal anaesthesia with hyperbaric prilocaine 2% in an ambulatory setting.

BACKGROUND Hyperbaric prilocaine 2% is a medium long-acting spinal anaesthetic. There are few data on time to recovery and rate of urinary retention after spinal administration of hyperbaric prilocaine 2%. This prospective study was carried out to evaluate the time to spontaneous micturition, quantify the rate of necessary bladder catheterizations, and identify the risk factors for urinary retention after intrathecal prilocaine administration. METHODS ASA I/II patients (16-80 yr) undergoing ambulatory lower limb surgery were enrolled and received spinal anaesthesia using hyperbaric prilocaine 2% (60 mg). Ringer's lactate was administered for peroperative volume replacement. Bladder ultrasound was performed hourly until spontaneous micturition or catheterization, when bladder filling reached 600 ml, and they were unable to urinate spontaneously. RESULTS Eighty-six patients completed the study (49 males and 37 females). Mean (sd) fluid administration was 1200 (499) ml until either micturition or catheterization; 37.8% of the women and 12.2% of the men required catheterization (P=0.009). Mean (sd) time between spinal anaesthesia and catheterization was 190 (88) min, and 260 (61) min to micturition (P<0.0001). Age <40 or >60 yr and female gender were predisposing factors for urinary retention. CONCLUSIONS After spinal anaesthesia with hyperbaric prilocaine 2% (60 mg) for ambulatory lower limb surgery, 23% of patients required postoperative urinary catheterization. Postoperative bladder ultrasound and early catheterization are essential to avoid bladder distension and facilitate discharge in patients after intrathecal prilocaine 2% administration in ambulatory surgery.