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New guidelines for postoperative nausea and vomiting

October 17, 2006

DURHAM, N.C. - After five years of reviewing the latest research findings, a panel of experts led by a Duke University Medical Center anesthesiologist has developed new guidelines to help physicians reduce the occurrence of nausea and vomiting in patients after surgery.

Despite decades of advances in surgical techniques and improved anesthetic agents, one out of three patients still experiences postoperative nausea and vomiting, said Duke anesthesiologist Tong J. Gan, M.D., leader of the panel that developed the guidelines. Such conditions not only can lead to patient dissatisfaction, but also can lengthen hospital stays and prolong recovery, he said.

Gan presented the new guidelines, one set for adults and one for children, on Monday, Oct. 16, at the annual scientific meeting of the American Society of Anesthesiologists, in Chicago. The panel, which included anesthesiologists, surgeons, pharmacists, nurse anesthetists and biostatisticians, was commissioned and supported by the Society of Ambulatory Anesthesia.

The guidelines incorporate the use of new drugs, known as antiemetics, which patients receive prior to surgery to prevent nausea and vomiting. The researchers also found that combining different classes of antiemetics added to their effectiveness.

The guidelines also provide new information that should help physicians identify which patients are at the greatest risk for nausea and vomiting and therefore should receive antiemetics prior to surgery.

"The results of more than 250 trials of antiemetics have been published since the last guidelines were developed five years ago," Gan said. "The new guidelines incorporate much of this new information and provide physicians with up-to-date strategies for preventing and treating postoperative nausea and vomiting."

Children are twice as likely as adults to develop postoperative nausea and vomiting, Gan said, and the panel developed a simple four-point scoring system for identifying those children at highest risk. The four factors are: when a surgical procedure lasts more than 30 minutes; when children are three years of age or older; when there is a family history of postoperative nausea and vomiting; and when the surgery is to correct strabismus, or crossed eyes.

"If one of these risk factors is present, then there is a 10 percent chance of postoperative nausea and vomiting," Gan said. "Each additional factor adds another 20 percent chance, meaning that a child with all four would be at a 70 percent risk. Since the previous guidelines were developed, there have been a number of effective antiemetics approved for use in children, and we would recommend that children identified as being at high risk should be given a combination of these drugs."

For adults, the factors that elevate risk include being female, being a nonsmoker and having a family history of motion sickness or postoperative nausea and vomiting. Also, long surgeries, or those that use nitrous oxide as an agent of general anesthesia, increase risk, Gan said, as does the use of opioids to control pain after surgery.

The panel concluded that being obese does not increase a patient's chances of suffering from nausea and vomiting, as was previously thought, Gan said. Additionally, giving patients 100 percent oxygen during surgery - a common preventive strategy - does not appear to be effective in controlling nausea and vomiting.

The research team also looked at nontraditional preventive methods.

"We have seen more support among the medical community for the use of acupuncture before and during surgery to control postoperative nausea and vomiting," said Gan, who recently conducted a study which found that the ancient Chinese practice is effective for managing the disorder in women undergoing major breast surgery. [link] "However, we also found that hypnosis before surgery was not effective as a preventive measure."

According to Gan, postoperative nausea and vomiting does not receive enough attention from the medical community.

"There are more than 35 million surgical procedures performed each year in the United States, so this is an extremely important health care issue," Gan said. "It is also an issue that most physicians do not take seriously enough; they see it as a short-term nuisance that will soon pass. However, studies have shown that nausea and vomiting after surgery is the major factor influencing whether or not patients are satisfied with their surgery."

The issue is also important for patients who go home in the afternoon after having surgery in the morning.

"More than 70 percent of all surgeries in the United States are performed as day cases, and the persistence of nausea and vomiting symptoms beyond discharge after surgery pose a great challenge to both patients and their physicians," Gan said. "So it is important to consider postoperative nausea and vomiting before surgery and have an effective strategy to manage it."

Duke University Medical Center