Fast-track interventions of low-dose opioid-based general anaesthesia and early tracheal extubation in adults undergoing cardiac surgery

Review question

Fast-track cardiac care involves early removal, within eight hours of heart surgery, of the tube that provides mechanical breathing support (called early tracheal extubation) to enable cardiac surgery. This review examined evidence on the effectiveness and safety of fast-track care compared with conventional (not fast-track) care. We have updated the published evidence that we identified in 2012. It is now current to March 2016.

Background

In the past, adults were given high-dose opioid-based anaesthesia for cardiac surgery and were provided with mechanical breathing support overnight in an intensive care unit after surgery. Now, many surgical units remove the tube that provides mechanical breathing support when the patient is on the operating table or within hours after cardiac surgery. They use time-directed protocols for removing breathing support. Some patients recover in an intensive care unit (ICU) or in a dedicated unit outside the ICU. It is important to improve hospital efficiency by using safe fast-track interventions.

Study characteristics

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.

Key findings and quality of evidence

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.

Conclusion

Fast-track cardiac care is safe in patients considered to be at low to moderate risk of death after surgery.

Authors' conclusions: 

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.

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Background: 

Fast-track cardiac care is a complex intervention involving several components of care during cardiac anaesthesia and in the postoperative period, with the ultimate aim of early extubation after surgery, to reduce length of stay in the intensive care unit and in the hospital. Safe and effective fast-track cardiac care may reduce hospital costs. This is an update of a Cochrane review first published in 2003, updated in 2012 and updated now in 2016.

Objectives: 

To determine the safety and effectiveness of fast-track cardiac care compared with conventional (not fast-track) care in adult patients undergoing cardiac surgery. Fast-track cardiac care intervention includes administration of low-dose opioid-based general anaesthesia or use of a time-directed extubation protocol, or both.

Search strategy: 

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 5), MEDLINE (January 2012 to May 2015), Embase (January 2012 to May 2015), the Cumulative Index to Nursing and Allied Health Literature (CINAHL; January 2012 to May 2015) and the Institute for Scientific Information (ISI) Web of Science (January 2012 to May 2015), along with reference lists of articles, to identify additional trials. We applied no language restrictions.

Selection criteria: 

We included all randomized controlled trials of adult cardiac surgical patients (coronary artery bypass grafts, aortic valve replacement, mitral valve replacement) that compared fast-track cardiac care and conventional (not fast-track) care groups. We focused on the following fast-track interventions, which were designed for early extubation after surgery: administration of low-dose opioid-based general anaesthesia during cardiac surgery and use of a time-directed extubation protocol after surgery. The primary outcome was risk of mortality. Secondary outcomes included postoperative complications, reintubation within 24 hours of surgery, time to extubation, length of stay in the intensive care unit and in the hospital, quality of life after surgery and hospital costs.

Data collection and analysis: 

Two review authors independently assessed trial quality and extracted study data. We contacted study authors for additional information. We calculated a Peto odds ratio (OR) for risk of mortality and used a random-effects model to report risk ratio (RR), mean difference (MD) and 95% confidence intervals (95% CIs) for all secondary outcomes.

Main results: 

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).

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