Surgical mortality dropping worldwide

Robin Wulffson MD's picture
surgery, general anesthesia, risk, mortality

The prospect of a surgical procedure is often extremely stressful. However a new study has some good news for individuals facing “going under the knife.” Researchers affiliated with the University of Western Ontario (London, Canada) conducted a study to determine perioperative mortality rates in developing and developed nations. Perioperative mortality is a death that occurs during a surgical procedure; the death is related to anesthesia and/or the surgical procedure itself. They published their findings in the September 22 issue of The Lancet.

The researchers note that the magnitude of risk of death related to surgery and anesthesia is not well understood. Therefore, they conducted a study to assess whether the risk of perioperative and anesthetic-related mortality has decreased over the past five decades and whether rates of decline have been comparable in developed and developing countries.


The researchers conducted a systematic review to identify all studies published up to February, 2011, in any language, with a sample size of over 3,000, which reported perioperative mortality across a mixed surgical population who had undergone general anesthesia. Two authors, using standard forms, independently identified studies for inclusion and extracted information on rates of anesthetic-related mortality, perioperative mortality, cardiac arrest, American Society of Anesthesiologists (ASA) physical status, geographic location, human development index (HDI), and year. The primary outcome measure was mortality primarily due to anesthesia. Secondary outcome measures were anesthetic contributory mortality, total perioperative mortality, and cardiac arrest.

The researcher identified 87 studies that met their inclusion criteria; in all, more than 21.4 million anesthetic administrations were administered given to patients undergoing general anesthesia for surgery. The investigators found that mortality solely attributable to anesthesia declined over time, from 357 per million before the 1970s to 52 per million in the 1970s—1980s, and 34 per million (29—39) in the 1990s—2000s. Total perioperative mortality decreased over time, from 10,603 per million before the 1970s, to 4,533 per million (4,405—4,664) in the 1970s—1980s, and 1,176 per million (1,148—1,205) in the 1990s—2000s. Meta-regression showed a significant relation between risk of perioperative and anesthetic-related mortality and HDI. (Meta-regression is an analytic technique that further validates the findings of several studies.) Baseline risk status of patients who presented for surgery as shown by the ASA score increased over the decades. Thus, the patients who more recently underwent surgery had, on the average, a higher surgical risk (i.e., less healthy patients and/or more complex surgery).

The authors noted that despite increasing patient baseline risk, perioperative mortality has declined significantly over the past 50 years; furthermore, the greatest decline has occurred in developed nations. They recommended that global priority should be given to reducing total perioperative and anesthetic-related mortality by evidence-based best practice in developing nations.

Reference: The Lancet

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