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Abstract
Background and Aims The effects of intrathecal morphine (IM) are well studied on analgesia, nausea and vomiting but not on bladder function. We aimed to determine the effects of IM on urodynamics in women having spinal anesthesia (SA) for Cesarean section (CS).
Methods The primary outcome variable was the effect of intrathecal opioids on urinary urodynamics; the secondary outcome was the need for urinary bladder re-catheterization.
56 patients undergoing elective CS under SA received a mixture of hyperbaric prilocaine and sufentanil with the addition of 100mcg morphine or NaCl.
We evaluated bladder volume, micturition volume, peak flow, duration of miction and postmicturition residual volume (PMRV) before and after CS.
Independent continuous variables were compared by X2 test or Mann-Whitney test. Repeated bladder functions data were compared by the analysis of variance for repeated measures with mixed models and a Bonferroni test.
Results The addition of IM prolonged the time to recovery of bladder awareness (8.1 hours ± 3.6 - 8[6–10] v.s. 5.3 hours ± 1.3 - 6[4–6], p<0.001), and time to micturition by 25% (10.4 hours ± 3.3 - 10[8–12] and 6.8 hours ± 1.6 - 6[6–8], p<0.001). Two patients who received IM required a single bladder catheterization (Figure 1).
Conclusions Our study is the first randomized double-blind trial to investigate the effects of IM on urodynamics after CS under SA. The addition of IM delayed voiding by 3 hours with no effect on urodynamics or PMRV. Future studies should investigate the risk-benefit ratio of adding IM in SA for elective CS.