Abstract: We included 28 trials (4438 participants) in the updated review. We considered most participants to be at low to moderate risk of death after surgery. We assessed two studies as having low risk of bias and 11 studies high risk of bias. Investigators reported no differences in risk of mortality within the first year after surgery between low-dose versus high-dose opioid-based general anaesthesia groups (OR 0.53, 95% CI 0.25 to 1.12; eight trials, 1994 participants, low level of evidence) and between a time-directed extubation protocol versus usual care (OR 0.80, 95% CI 0.45 to 1.45; 10 trials, 1802 participants, low level of evidence). Researchers noted no significant differences between low-dose and high-dose opioid-based anaesthesia groups in the following postoperative complications: myocardial infarction (RR 0.98, 95% CI 0.48 to 1.99; eight trials, 1683 participants, low level of evidence), stroke (RR 1.17, 95% CI 0.36 to 3.78; five trials, 562 participants, low level of evidence) and tracheal reintubation (RR 1.77, 95% CI 0.38 to 8.27; five trials, 594 participants, low level of evidence). Comparisons with usual care revealed no significant differences in the risk of postoperative complications associated with a time-directed extubation protocol: myocardial infarction (RR 0.59, 95% CI 0.27 to 1.31; eight trials, 1378 participants, low level of evidence), stroke (RR 0.85, 95% CI 0.33 to 2.16; 11 trials, 1646 participants, low level of evidence) and tracheal reintubation (RR 1.34, 95% CI 0.74 to 2.41; 12 trials, 1261 participants, low level of evidence). Although levels of heterogeneity were high, low-dose opioid anaesthesia was associated with reduced time to extubation (reduction of 4.3 to 10.5 hours, 14 trials, 2486 participants, low level of evidence) and length of stay in the intensive care unit (reduction of 0.4 to 7.0 hours, 12 trials, 1394 participants, low level of evidence). Use of a time-directed extubation protocol was associated with reduced time to extubation (reduction of 3.7 to 8.8 hours, 16 trials, 2024 participants, low level of evidence) and length of stay in the intensive care unit (reduction of 3.9 to 10.5 hours, 13 trials, 1888 participants, low level of evidence). However, these two fast-track care interventions were not associated with reduced total length of stay in the hospital (low level of evidence). Low-dose opioid-based general anaesthesia and time-directed extubation protocols for fast-track interventions have risks of mortality and major postoperative complications similar to those of conventional (not fast-track) care, and therefore appear to be safe for use in patients considered to be at low to moderate risk. These fast-track interventions reduced time to extubation and shortened length of stay in the intensive care unit but did not reduce length of stay in the hospital.

Plain-language summary: We found 28 relevant randomized controlled studies, conducted between 1994 and 2015. Most of the 4438 adults who participated in these studies were undergoing first-time elective coronary artery graft bypass or valve replacement surgery, or both. They were at low to moderate risk of death after surgery. Eighteen studies examined the use of low-dose opioid-based general anaesthesia. Sixteen studies assessed how effective the protocols were in guiding staff to remove the tube that provided breathing support within eight hours after surgery. We found no differences in risk of death in the first year after surgery (18 trials, 3796 participants) nor in complications after surgery such as the need to replace the tracheal tube after surgery (17 trials, 1855 participants) and occurrence of myocardial infarction (16 trials, 3061 participants) or stroke (16 trials, 2208 participants), when we examined both types of interventions. Occurrences of acute renal failure, major bleeding, sepsis and wound infection also were not different. We rated the quality of evidence as low for both mortality and postoperative complications. Tracheal tubes were removed from adults in the fast-track care group up to a half day earlier than for those in the conventional care group. The fast-track group spent less time in the intensive care unit, but length of time spent in the hospital was similar between groups. The quality of evidence was low because of study limitations and unexplained variation in study findings. Large trials were few, and only one trial was designed to study postoperative effects of myocardial infarction, stroke or death. Our results did not apply to ‘high-risk' patients who had multiple concurrent health problems or to settings in which a short-acting opioid (remifentanil) was used for general anaesthesia. Fast-track cardiac care is safe in patients considered to be at low to moderate risk of death after surgery.