High-dose versus low-dose opioid anesthesia in adult cardiac surgery: A meta-analysis

Study Objective. We performed a systematic comparison of high-dose and low-dose opioid anesthesia in cardiac surgery. Design Systematic review and meta-analysis of randomized controlled trials (RCTs). Setting Operating room. Patients 1400 adult patients undergoing cardiac surgery using general anesthesia. Interventions All RCTs comparing the effects of various doses of intravenous opioids (morphine, fentanyl, sufentanil, and remifentanil) during adult cardiac surgery using general anesthesia published until May 2018 (full-text English articles reporting data from human subjects) were included. Measurements Primary outcome was intensive care unit (ICU) length of stay (LOS). Secondary outcomes were ventilation time, use of vasopressors, perioperative myocardial infarction, perioperative stroke, and hospital LOS. Main results Eighteen articles were included (1400 patients). There was no difference in ICU LOS between studies using high or low dose of opioids (both short-acting and long-acting) (standard mean difference [SMD]−0.02, 95%CI: −0.15–0.11, P = 0.74). Similarly, there was no difference in secondary outcomes of ventilation time (SMD−0.27, 95%CI: −0.63–0.09, P = 0.14), use of vasopressors (OR 0.61, 95%CI: 0.29–1.30, P = 0.20), myocardial infarction (risk difference 0.00, 95% CI: −0.02–0.03, P = 0.70), stroke (RD 0.00, 95% CI: −0.01–0.01, P = 0.92) and hospital LOS (SMD 0.03, 95% CI: −0.26–0.33, P = 0.84). At meta-regression, there was no effect of age, gender, or type of opioid on the difference between groups. Conclusions Our data suggest that low-dose opioids, both short acting and long acting, are safe and effective to use in adult cardiac surgery patients, independent of the clinical characteristics of the patients and the type of opioid used. In view of the current opioid epidemic, low-dose opioid anesthesia should be considered for cardiac surgery patients.