Systematic Reviews, Meta-Analyses, Critical Appraisal, and Evidence-Based Practice Guidelines — WACS Viva & Clinical Scenarios (Statistics & Evidence-Based Practice)

Exam-style systematic reviews, meta-analyses, critical appraisal, and evidence-based practice guidelines viva scenarios with examiner probes and model answers…

Scenarios covered

• SCENARIO 1: You are presented with a published forest plot from a high-impact meta-analysis evaluating the efficacy of intravenous dexamethasone versus placebo for the prevention of postoperative nausea and vomiting (PONV) in adult surgical patients. The pooled relative risk is 0.65 (95% CI 0.55 to 0.77), the Cochran Q test has a p-value of 0.01, and the I² statistic is 68%. As a journal club lead, how do you systematically interpret the diamond, the individual study weights, the heterogeneity metrics, and decide between a fixed-effects versus random-effects model?
• SCENARIO 2: Your departmental head requests a formal appraisal of an international guideline on perioperative fasting and pulmonary aspiration prevention before implementing it in your institution. Outline how you will use the AGREE II instrument and the GRADE (Grading of Recommendations Assessment, Development and Evaluation) framework to evaluate the methodological rigor, stakeholder involvement, and applicability of this guideline in your resource-limited practice.
• SCENARIO 3: You are critically appraising an open-label randomised trial comparing hyperbaric versus isobaric ropivacaine for spinal anaesthesia in lower limb orthopaedic surgery. Using the Cochrane Risk of Bias 2 (RoB 2) tool, systematically evaluate the five standard bias domains and explain the methodological vulnerability of an open-label design on subjective endpoints such as sensory block level and duration.
• SCENARIO 4: You examine a funnel plot constructed for a systematic review investigating the use of thoracic epidural analgesia on postoperative mortality after major abdominal surgery. The funnel plot demonstrates marked visual asymmetry with a complete absence of small negative studies on the bottom left. How do you assess publication bias, explain the mathematical basis of Egger's test, and discuss non-publication causes of funnel plot asymmetry?