Late afternoon may be the least desirable time to have surgery, according to a study that finds certain adverse effects are more common after 3 p.m.

In a review of more than 90,000 surgeries performed at their medical center, Duke University researchers found that negative effects related to anesthesia - most often pain or nausea - were most common after late-afternoon procedures.

For example, a patient’s odds of suffering postoperative nausea and vomiting, wound infection or some other “harm” were three times higher if the surgery began at 3 p.m. versus 8 a.m. - though few patients had such problems at either time.

Along with postoperative nausea, inadequate management of patients’ pain during and after surgery was the most common problem reported.

According to the study authors, there are a number of potential reasons for the late-afternoon slump, including doctors’ late-day fatigue and hospital shift rotations. It’s also possible that people are more susceptible to pain or nausea late in the day - perhaps from lack of food all day or the stress of waiting to go under the knife.

“We believe that identifying the specific periods when problems are most likely to occur is an important step in the overall process of making surgery safer and ensuring that patients have a good experience,” lead researcher Dr. Melanie Wright said in a statement.

She and her colleagues at the Durham, North Carolina, medical center report their findings in the journal Quality & Safety in Health Care.

For their study, the researchers analyzed a database kept by the center’s anesthesiology department, tracking adverse events among 90,159 surgeries performed over four years.

They found 31 instances of error, such as giving patients the wrong dose of anesthesia medication, and 2,662 instances of adverse events during or soon after surgery.

In all, adverse effects were most common after about 3 p.m.

In addition, the researchers found, “administrative delays” - waiting for lab test results, doctors running late - were more common in late afternoon. This, they speculate, might have contributed to the higher risk of anesthesia-related problems.

The researchers are now planning a follow-up study that will analyze each step in the surgery process to try to weed out the factors that separate procedures done in the morning from those done late in the day.

SOURCE: Quality & Safety in Health Care, August 2006.