Does regional anesthesia improve outcomes, mortality, and major morbidity for patients undergoing intermediate- to high-risk surgery? This question has been a hot topic in anesthesiology for several decades. The latest contribution to the debate is an analysis of Cochrane reviews in order to summarize the effects of neuraxial anesthesia on the perioperative rates of death, chest infection, and myocardial infarction by Dr. Joanne Guay, Department of Anesthesiology, CSSS Rouyn-Noranda, Rouyn-Noranda, Québec, Canada, and colleagues from Canada and the United States. Their results are discussed in the article “ Neuraxial Anesthesia for the Prevention of Postoperative Mortality and Major Morbidity: An Overview of Cochrane Systematic Reviews,” which was published in this month’s issue of Anesthesia and Analgesia. The authors concluded that compared to general anesthesia, neuraxial anesthesia may decrease the 30-day mortality rate after surgery.
The methodology used in this study was innovative; the authors assessed previous Cochrane reviews of this topic and reanalyzed the results. They retrieved 9 systematic reviews that included 117 trials, but rejected the majority, which did not meet their inclusion criteria, and thus retained only 40 trials for analysis. This review could therefore be considered a “super Cochrane review.” The remaining 40 trials were subjected to a rigorous statistical evaluation.
In brief, compared with general anesthesia, neuraxial anesthesia decreased the 30-day mortality rate from 7.9% to 5.2% and reduced the risk of pneumonia (7.6% for neuraxial anesthesia vs. 16.8% for general anesthesia), but had no effect on the incidence of myocardial infarction. The addition of general anesthesia to neuraxial blockade abolished these beneficial effects with the possible exception of the risk of pneumonia where the results were equivocal. The authors assessed the quality of the evidence as moderate, indicating that further research is likely to have an important impact on the confidence of the estimate of the effect and may even change the estimate. Key methodological deficiencies identified were the absence of blinding and the failure to report side effects of neuraxial blockade.
As noted by Drs. Stavros G. Memtsoudis and Spencer S. Liu, Department of Anesthesiology, Hospital for Special Surgery, Weill-Cornell Medical College, New York, New York, in the accompanying editorial titled “Do Neuraxial Techniques Affect Perioperative Outcomes? The Story of Vantage Points and Number Games,” “…while the literature on anesthetic and analgesic techniques and their effect on outcome is far from definitive, it is clear that the interpretation of studies depends on factors as simple as definitions chosen and as complex as the discussion regarding our role as anesthesiologists in the wider health care system.”
The important benefits of neuraxial blockade, importantly without concomitant general anesthesia, provide further support for the proponents of regional anesthesia. Other anesthesiologists will note that many of the studies cited were published in the 1980s and 1990s and question their relevance to practice in the 21st century. This is an important and challenging paper. Controversy and debate are good for the specialty – a must read for all anesthesiologists.