Intrathecal morphine increases the incidence of urinary retention in orthopaedic patients under spinal anaesthesia.

BACKGROUND Morphine injected into the subarachnoid space enhances the analgesic effects of spinal anaesthesia, improving the patient's comfort in the postoperative period. However, it is likely to be associated with adverse side effects that reduce patient satisfaction, e.g., urine retention. The aim of the present study was to evaluate the incidence of urine retention in patients receiving spinal anaesthesia combined with intrathecal morphine. METHODS The postoperative course of 30 patients undergoing orthopaedic surgical procedures was analysed. Patients were divided into two groups: the control group (BSH; 16 individuals anaesthetised with a 0.5% hyperbaric solution of bupivacaine) and the experimental group (BSH + MF; 14 individuals anaesthetised with a 0.5% hyperbaric solution of bupivacaine with the addition of 0.2 mg morphine). The following parameters were analysed: duration of anaesthesia, time to miction, time to urgency and need to introduce a urinary catheter. RESULTS There were no statistically significant differences in the duration of anaesthesia, incidence of hypogastric discomfort/difficulties in urination, time to hypogastric discomfort or duration of discomfort. Patients receiving intrathecal morphine were characterised by longer time to miction, higher incidence of urinary catheterisation and longer time between anaesthesia and urinary catheterisation. CONCLUSIONS Patients receiving spinal anaesthesia with a 0.5% hyperbaric solution of bupivacaine combined with intrathecal morphine were demonstrated to have a higher incidence of urinary catheterisation, longer time to urinary catheterisation and longer time to miction compared to patients receiving only local anaesthetics.