Patient-controlled versus nurse-controlled analgesia after cardiac surgery -: a meta-analysis

Background: Patient-controlled analgesia (PCA) has been advocated as superior to conventional nurse-controlled analgesia (NCA) with less risk to patients. This systematic review and meta-analysis sought to determine whether PCA improves clinical and resource outcomes when compared with NCA. Methods: A comprehensive search was undertaken to identify all randomized controlled trials of PCA vs NCA. Medline, Cochrane Library, Embase, and conference abstract databases were searched from the date of their inception to August 2005. The primary postoperative outcome was defined as mean visual analogue scale (VAS) scores. Secondary postoperative outcomes included cumulative morphine equivalents, intensive care unit (ICU) and hospital length of stay, postoperative nausea and vomiting, sedation, respiratory depression, and all-cause mortality. Odds ratios or weighted mean differences (WMD) and their 95% confidence intervals (CI) were calculated for discrete and continuous outcomes, respectively. Results: Ten randomized trials involving 666 patients were included. Compared to NCA, PCA significantly reduced VAS at 48 hr (WMD -0.73, 95% Cl -1.19, -0.27), but not at 24 hr (WMD -0.19, 95% CI -0.61, 0.24). Cumulative morphine equivalents consumed were significantly increased at 24 hr (WMD 6.84 mg, 95% CI 0.97, 12.72 mg), and at 48 hr (WMD 10.46 mg 95% CI 2.02, 18.9 mg) for PCA compared with NCA. Ventilation times, length of ICU stay, length of hospital stay, patient satisfaction scores, sedation scores, and incidence of postoperative nausea and vomiting, respiratory depression, severe pain, discontinuations, and death were not significantly different between groups, but these outcomes were generally under-reported. Conclusions: In postcardiac surgical patients, PCA increases cumulative 24 and 48 hr morphine consumption, and improves 48-hr VAS compared with NCA.