A paper by a couple of public health researchers created some media buzz because it suggested that cardiac surgeons' performance deteriorated when they took even 1 day off from surgery.

For a sample of over 56,000 patients undergoing coronary artery bypass grafting (CABG) in Pennsylvania over a 5-year period, the average 1-day mortality was 0.62% and average in-hospital mortality was 2.72%. That means 349 patients died within 24 hours and 1532 died in-hospital.

"An additional day without performing any inpatient procedure was associated with an increase in 1-day mortality of nearly 0.05 percentage points, or 7.4% relative to the sample mean. The absolute effect on in-hospital mortality was larger at nearly 0.07 percentage points, but on a relative basis it was smaller, 2.5%. The effect was smaller in relative magnitude and not statistically significant when temporal distance was defined as days since last CABG rather than last inpatient procedure."

Interestingly, "The effect was smaller in relative magnitude and not statistically significant when temporal distance was defined as days since last CABG rather than last inpatient procedure [of any kind]."

The authors also noted that costs of hospitalizations actually fell after surgeons took days off, which they ascribed to the ordering of fewer tests because complications were not being recognized, without benefit of data to prove that assumption.

Assuming the investigators' methods were correct, what have we learned from this?

Here's what the authors said: "In this study, the data did not allow us to parse out which of the multiple skills that surgeons use to perform CABG procedures were depreciating and how rapidly. They could be primarily cognitive in nature and thus consistent with our hypothesis of inattentive care, which in turn is supported by the results we report here. They could also include dexterity or the ability to manage a surgical team." Nothing in this paragraph is supported by the data.

They also acknowledged that the true reason for the association of days off and increased mortality could not be discerned from the administrative database they used.

The number of unmeasured confounders would be impossible to estimate and include patient's disease severity, time of day of surgery (unavailable to the investigators, but recently shown to be a significant outcome factor in a paper), anesthesiologist, and OR and floor nursing staff experience and numbers, to name a few.

Speaking of estimates, the authors made many assumptions, including this beauty: "Healthier patients are unlikely to die in the short term unless the procedure was performed very poorly." That is not necessarily so. Sometimes people die after surgery that was done perfectly.

The authors would have us believe that surgeons develop problems with dexterity, forget how to do procedures, and lose their ability to recognize complications after even 1 day of not operating.

Let's take the last of those points first. Since not every surgeon has to manage a complication every day, it is hard to believe that taking a day or two off from operating would have any impact on recognition or management of complications.

Although they cited some literature that says worker productivity on assembly lines deteriorates with increased time between tasks, its relationship to surgeon performance is unclear, especially considering that the increased mortality was not CABG specific.

Even if the authors’ conclusions are true, what would be the remedy for this situation?

Physicians are already under fire for working too many hours. Would the authors prefer tired surgeons with optimal dexterity and awareness or rested surgeons with slightly diminished skills?

In an online discussion, someone suggested that dexterity could be improved if surgeons warmed up by playing video games, again with very little data to support that premise. Even if a warm-up were shown to be effective, it would have no impact on the recognition or management of complications.

I hope I never need a CABG, but if I do, I am not going to worry about what my surgeon did on his or her weekend off.