No Difference in Risk by Time of Day, Week, or Year—Study Allays Concerns about Effects of Fatigue
Newswise — San Francisco, CA. (November 23, 2011) – The timing of surgical procedures—afternoon versus morning or Friday versus Monday—doesn't affect the risk of death after surgery, concludes a study in the December issue of Anesthesia & Analgesia, official journal of the International Anesthesia Research Society (IARS).
The findings help to alleviate concerns that fatigue may contribute to an increased rate of safety problems for operations performed later in the workday or workweek. The study also shows no increase in mortality in the summer months, when new residents begin work. No Variation in Mortality by Timing of OperationLed by Dr Daniel I. Sessler of The Cleveland Clinic, the researchers analyzed the outcomes of 32,001 elective surgeries performed from 2005 to 2010. The risk of death within 30 days after surgery was analyzed according to time of day of the procedure (from 6:00 am to 7:00 pm), day of the week, and month of the year.
The researchers took steps to eliminate emergency surgical procedures from the study, along with certain types of surgeries that are commonly performed on an urgent basis. As a "negative control," differences in outcome by phase of the moon were analyzed as well.
The overall risk of death within 30 days after surgery was 0.43 percent. After adjustment for other factors, mortality risk was not significantly different for patients operated on at different times of day. Neither was there any evidence of an increased risk of death for operations performed later in the workweek.
There was also no difference in mortality by time of year. Specifically, risk was not increased for operations performed in July and August, which is when most new residents start working in teaching hospitals. As expected, there was no difference by phase of the moon.
A similar analysis found no difference in complication rates for surgeries performed at different times of the day, days of the week, or months of the year. The overall rate of in-hospital complications was 13 percent.
"Human factors such as fatigue, circadian rhythms, scheduling, and staffing may have an impact on patient care across medical specialties," according to Dr Sessler and colleagues. Some previous studies have raised concerns of a decline in safety for operations performed later in the day.
The new study suggests that the timing of surgery does not affect the safety of surgery. "Elective surgery thus appears to be comparably safe at any time of the workday, any day of the workweek, and in any month of the year in our teaching hospital," Dr Sessler and colleagues conclude. They note that their results apply to hospitals that perform "high risk surgery in a high-risk population" and may not apply to other types of hospitals.
The findings have important implications for OR scheduling, according to an accompanying editorial by Drs Franklin Dexter and Alan P. Marco. The results suggest that facilities can decide whether to add additional operating rooms or run the scheduled operating rooms late on busy days based entirely on the economic tradeoffs, because patient safety is not compromised either way.
About the IARSThe International Anesthesia Research Society is a nonpolitical, not-for-profit medical society founded in 1922 to advance and support scientific research and education related to anesthesia, and to improve patient care through basic research. The IARS contributes nearly $1 million annually to fund anesthesia research; sponsors an annual forum for anesthesiology leaders to share information and ideas; maintains a worldwide membership of more 15,000 physicians, physician residents, and others with doctoral degrees, as well as health professionals in anesthesia-related practice; sponsors the SmartTots initiative in conjunction with the FDA; and publishes the journal Anesthesia & Analgesia. Additional information about the society and the journal may be found at the IARS website.
About Anesthesia & AnalgesiaAnesthesia & Analgesia was founded in 1922 and was issued bi-monthly until 1980, when it became a monthly publication. A&A is the leading journal for anesthesia clinicians and researchers and includes more than 500 articles annually in all areas related to anesthesia and analgesia, such as cardiovascular anesthesiology, patient safety, anesthetic pharmacology, and pain management. The journal is published on behalf of the IARS by Lippincott Williams & Wilkins (LWW), a division of Wolters Kluwer Health.