Wong, Jean

Objective This systematic review and meta-analysis aim to evaluate the risk factors associated with postoperative opioid-induced respiratory depression (OIRD). Design Systematic review and meta-analysis. Data sources PubMed-MEDLINE, MEDLINE in-process, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, PubMed and Clinicaltrials.gov (January 1946 to November 2017). Eligibility criteria The inclusion criteria were: (1) adult patients 18 years or older who were administered opioids after surgery and developed postoperative OIRD (OIRD group); (2) all studies which reported both OIRD events and associated risk factors; (3) all studies with reported data for each risk factor on patients with no OIRD (control group) and (4) published articles in English language. Data analysis We used a random effects inverse variance analysis to evaluate the existing evidence of risk factors associated with OIRD. Newcastle-Ottawa scale scoring system was used to assess quality of study. Results Twelve observational studies were included from 8690 citations. The incidence of postoperative OIRD was 5.0 cases per 1000 anaesthetics administered (95% CI: 4.8 to 5.1; total patients: 841 424; OIRD: 4194). Eighty-five per cent of OIRD occurred within the first 24 hours postoperatively. Increased risk for OIRD was associated with pre-existing cardiac disease (OIRD vs control: 42.8% vs 29.6%; OR: 1.7; 95% CI: 1.2 to 2.5; I 2 : 0%; p<0.002), pulmonary disease (OIRD vs control: 17.8% vs 10.3%; OR: 2.2; 95% CI: 1.3 to 3.6; I 2 : 0%; p<0.001) and obstructive sleep apnoea (OIRD vs control: 17.9% vs 16.5%; OR: 1.4; 95% CI: 1.2 to 1.7; I 2 : 31%; p=0.0003). The morphine equivalent daily dose of the postoperative opioids was higher in the OIRD group than in the control; (24.7±14 mg vs 18.9±13.0 mg; mean difference: 2.8; 95% CI: 0.4 to 5.3; I 2 : 98%; p=0.02). There was no significant association between OIRD and age, gender, body mass index or American Society of Anesthesiologists physical status. Conclusion 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.

Smoking increases the risk of postoperative morbidity and mortality. Smoking cessation before surgery reduces the risk of complications. The perioperative period may be a “teachable moment” for smoking cessation and provides smokers an opportunity to engage in long-term smoking cessation. Anesthesiologists as the perioperative physicians are well-positioned to take the lead in this area and improve not only short-term surgical outcomes but also long-term health outcomes and costs. Preoperative interventions for tobacco use are effective to reduce postoperative complications and increase the likelihood of long-term abstinence. If intensive interventions (counseling, pharmacotherapy, and follow-up) are impractical, brief interventions should be implemented in preoperative clinics as a routine practice. The “Ask, Advise, Connect” is a practical strategy to be incorporated in the surgical setting. All anesthesiologists should ask their patients about smoking and strongly advise smokers to quit at every visit. Directly connecting patients to existing counseling resources, such as telephone quitlines, family physicians, or pharmacists using fax or electronic referrals, greatly increases the reach and the impact of the intervention.