Purpose Urinary retention requiring catheterization carries the risk of infection. Neuraxial anesthesia causes transient impairment of bladder function ranging from delayed initiation of micturition to frank urinary retention. We undertook a review of the literature to determine the elements of neuraxial anesthesia and analgesia that prolong bladder dysfunction and increase the incidence of urinary retention. Methods We performed a systematic search of the PubMed, MEDLINE, and EMBASE databases (from January 1980 to January 2011) to identify studies where neuraxial anesthesia and/or analgesia were employed and at least one of the following outcomes was reported: urinary retention, time to micturition, or post void residual. We included randomized controlled trials and observational studies published in the English language and we excluded case reports. The randomized trials were graded according to the Jadad score. Principal findings Our search yielded 94 studies, and in 16 of these studies, the authors reported time to micturition after intrathecal anesthesia of varying local anesthetics and doses. Intrathecal injections were performed in 41 of these studies, epidural anesthesia/analgesia was used in 39 studies, and five studies involved both the intrathecal and epidural routes. Meta-analysis was not possible because of the heterogeneity of interventions and reported outcomes. The duration of detrusor dysfunction after intrathecal anesthesia is correlated with local anesthetic dose and potency. The incidence of urinary retention displays a similar trend and is further increased by the presence of neuraxial opioids, particularly long-acting variants. Urinary tract infection secondary to catheterization occurred rarely. Conclusions Neuraxial anesthesia/analgesia results in transient detrusor dysfunction. The duration of dysfunction depends on the potency and dose of medication used; however, it does not appear to result in significant morbidity.

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Relative beta power and spectral entropy when considered over the propofol effect-site range studied here increase in value, and correlate well with clinical assessment of sedation.