Cardiac surgery is commonly performed under general anesthesia with or without cardiopulmonary bypass. The benefits of using epidural analgesia in addition to general anesthesia are argued to reduce the risk of postoperative complications such as pneumonia, respiratory failure, and myocardial infarction.1 High thoracic epidural analgesia is believed to offer cardioprotective effects by increasing myocardial oxygen availability and reducing myocardial consumption.1 However, epidural analgesia does not come without complications; spinal cord depression caused by hematoma can result in paraplegia.1 Systemic anticoagulation required for cardiac surgery may increase the risk and incidence of epidural hematoma.1

Caring for a patient during cardiac surgery requires a specialized, multidisciplinary team including surgeons, anesthesiologists, and associated nursing and perfusion staff.2 These teams work together to ensure patient safety, and the best possible outcomes are achieved for each patient undergoing cardiac surgery. Although the use of epidural analgesia for patients undergoing cardiac surgery may be considered controversial in practice, studies have indicated that it may provide a benefit and improve patient outcomes. It is, therefore, important to evaluate the benefits and adverse effects of epidural analgesia for cardiac surgery patients.

Objective/s

The objective of the systematic review was to examine the evidence related to the use of perioperative epidural analgesia in adults undergoing cardiac surgery and its impact on perioperative mortality and cardiac, pulmonary, and neurological morbidity.

INTERVENTION/METHODS

The methods used in this review were consistent with the methods outlined in the Cochrane Handbook for Systematic Reviews of Interventions.3 A comprehensive search for randomized controlled trials was conducted in the following databases: Cochrane Central Register of Controlled Trials (2018, Issue 11), Ovid MEDLINE (Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Ovid MEDLINE Daily, and Ovid MEDLINE [1946 to November 19, 2018), EMBASE (1974 to November 19, 2018), the Cumulative Index to Nursing and Allied Health Literature (EBSCO Host), and Web of Science (Science Citation Index/Social Sciences Citation Index [November 19, 2018]). A search for gray literature was also conducted in relevant journals and websites. No languages or publications status restrictions were applied. All studies were independently screened, and those meeting the inclusion criteria were extracted independently and assessed for risk of bias using the original Cochrane "Risk of Bias" tool.3

The review compared the use of epidural analgesia to other modes of analgesia during cardiac surgery. Comparisons included systematic analgesia, regardless of route of administration, peripheral nerve blocks, intrapleural analgesia, and wound infiltration; spinal analgesia was excluded.

RESULTS

A total of 69 randomized controlled trials with 4860 participants were included in the review; 2404 received epidural analgesia, and 2456 received a different mode of analgesia. Included studies were published between 1988 and 2018. Most studies were conducted in university hospitals (n = 66), with the remaining 3 studies conducted in tertiary care center hospitals. The mean age of participants varied between 43.5 and 74.6 years. Types of surgery included coronary artery bypass graft, valve procedures, congenital heart surgery, and various other cardiac procedures. Most studies conducted surgery with cardiopulmonary bypass (n = 50); the remaining examined off-pump surgery (n = 15), and 4 studies included participants with and without cardiopulmonary bypass. Evidence related to the primary outcomes are presented hereinafter.

Epidural Analgesia Versus Systemic Analgesia

There may be no difference in mortality at 0 to 30 days between patients receiving epidural analgesia compared with systemic analgesia. There may be a reduction in myocardial infarction when comparing epidural analgesia with systematic analgesia. Epidural analgesia probably reduces the risk of atrial fibrillation or atrial flutter at 0 to 2 weeks. Epidural analgesia probably also reduces the duration of tracheal intubation and may reduce the risk of respiratory depression, but there is probably little or no difference in risk of pneumonia at 0 to 30 days. There may be no difference in cerebrovascular accidents at 0 to 30 days, and none of the included trials reported any epidural hematoma events at 0 to 30 days. Epidural analgesia reduces pain at rest and on movement up to 72 hours after surgery and may increase the risk of hypotension but may make little or no difference in the need for infusion of inotropics or vasopressors.

Epidural Analgesia Versus Other Comparators

Conclusions for all other comparators were uncertain because of the small numbers of trials and participants included in the review.

CONCLUSIONS

The findings of the review demonstrated that epidural analgesia provides better analgesia than systemic analgesia and may offer a reduction in the risk of myocardial infarction, atrial arrhythmia, and pulmonary complications. It was not possible to rule out a difference in mortality when comparing the 2 approaches, because of the insufficient number of participants included in the review and uncertain evidence. The number of studies and included participants comparing epidural analgesia with other techniques of regional anesthesia was very limited.

Implications for Practice and Research

The benefits of epidural analgesia for adults undergoing cardiac surgery have been assessed. Effects of epidural analgesia on 1-year mortality remain unclear because of insufficient data. Whether or not the actual demonstrated benefits justify a potential additional risk of epidural hematoma in this specific population may be a matter of patients' and carers' personal preferences. The evidence presented in the systematic review evaluating the effectiveness of epidural analgesia compared with other techniques of anesthesia was limited and thus of low quality.

Further research from large, well-designed trials is warranted to clarify potential benefits of epidural analgesia on 1-year mortality. Comparisons of epidural analgesia with other regional anesthetics techniques classified as superficial blocks (with no risks of epidural hematoma) and evaluating major outcomes would probably be interesting.

The findings of this review impact nurses working in the perioperative environment, in particular, anesthetic clinical nurse specialists, as they have a role and responsibility to actively improve patient outcomes and to evaluate processes and procedures ensuring best practice standards and patient safety.4

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