Risk factors for opioid-induced respiratory depression in surgical patients: a systematic review and meta-analyses

This systematic review and meta-analysis aim to evaluate the risk factors associated with postoperative opioid-induced respiratory depression (OIRD). Twelve observational studies were included and the incidence of postoperative OIRD was 5.0 cases per 1000 anaesthetics administered. Eighty-five per cent of OIRD occurred within the first 24 hours postoperatively. Patients with cardiac, respiratory disease and/or obstructive sleep apnoea were at increased risk for OIRD. Patients with postoperative OIRD received higher doses of morphine equivalent daily dose.