Heart surgery outcomes unaffected by time or day, season or moon phases

By Robert Higgs, The Plain Dealer
September 23, 2009, 1:15PM


Cleveland — The outcomes of elective heart surgeries do not differ based on the time of day the surgery was performed or the day of the week, the month of the year or the phase of the moon, according to a new Cleveland Clinic study.

Cleveland Clinic researchers, led by Drs. C. Allen Bashour and Daniel Sessler, analyzed the results of 18,597 elective coronary artery bypass graft surgeries performed at the hospital between 1993 and 2006.

"Our study found that the surgeries can be scheduled throughout the workday, any day of the work week or in any month of the year without compromising outcomes," Bashour said.

"None of the time factors we studied significantly affected the composite morbidity outcome." Bashour noted that the relationship between moon phase and medical events is a well-established urban legend. He said most studies have found that outcomes had nothing to do with whether there was a full moon, a new moon or any other moon phase. The Cleveland Clinic study yielded the same results.

The study can provide valuable insight into quality control measures, Sessler said. Outcome risk varies widely among different medical specialties, but errors are less frequent in specialties that establish strict protocols and safety procedures.

"To the extent that these systems are effective, one might expect them to compensate for daily circadian rhythm effects, workweek fatigue and training variability," he said.

"Consistent with this theory, our principle finding is that surgical start time, day of the week, month of the year and phase of the moon are not associated with outcomes because of well-established protocol-based practices that reduce variability." The results were published in the October issue of Anesthesiology, the journal of the American Society of Anesthesiologists.