A systematic review and meta-analysis of post-operative urinary retention with anaesthetic and analgesic modalities.

Abstract

Post-operative urinary retention (POUR) is defined as the inability to void with a full bladder following surgery [1]. Complications include delirium, pain, prolonged hospital admission, and long-term altered bladder contractility [2]. POUR is readily managed with catheterisation, but this can be emotionally traumatic and is associated with morbidity including urinary tract infection, trauma, and blockage [3,4]. This procedure may be difficult in patients with underlying urological pathology, who are at increased baseline risk of POUR [5]. We aimed to review and analyse current evidence regarding POUR rate with several anaesthetic and analgesic modalities, to enable informed decision-making regarding appropriate perioperative management around urinary retention. We utilised systematic review and meta-analytic methodology, in line with the PRISMA framework [6], and registered prospectively with the PROSPERO database (ID CRD42018111566). Five databases were searched with no time restriction. Terms were formulated to identify articles that reported urinary retention in adult patients with various anaesthetic and analgesic modalities. Studies included were peer-reviewed original randomised-controlled trials (RCTs) or observational studies (OS). Studies that included obstetric or trauma surgery, patients at extremes of body mass index, or multimodal pain management regimes were excluded. In many included studies, urinary retention was not a primary outcome measure. The search yielded 1533 results excluding duplicates. Studies were screened before full text review and comparison to inclusion and exclusion criteria. 44 studies were finally included. Data was extracted using a proforma. Level of evidence was assessed using Oxford Centre for Evidence-based Medicine (OCEM) criteria [7]. Risk of bias was assessed using the Cochrane Risk of Bias tool (RoB 2) for RCTs [8], and the RTI Item Bank for OS [9]. POUR rate was calculated for each study. Summary POUR rate with 95% confidence intervals (CI) and I2 were synthesised for each modality using random effects meta-analysis. If POUR rate was zero (as in studies with local and spinal anaesthesia and nerve or plexus blocks), studies were excluded from further analysis as standard error could not be calculated. Confidence intervals crossing zero and negative I2 values were truncated to zero [10]. Forest plots were constructed. Funnel plots were created to visually assess risk of publication bias. There were 17 OS and 27 RCTs, including a total of 5991 patients. 66% (n = 29) were OCEM level 1b as good quality RCTs. 23% (n = 10) were level 2b, as retrospective cohort studies or chart reviews. 11% (n = 5) were level 3b, as case control studies. 70% (n = 31) had some concerns for bias and 30% (n = 13) were high risk. No studies were considered low risk of bias. Risk of publication bias was low as assessed visually through funnel plot (Fig. 2). Diagnostic criteria for urinary retention was reported in 41% (n = 18) of studies, and not reported in 59% (n = 26). The breakdown of surgical specialties was as follows: