TUESDAY, March 12, 2002 (HealthDayNews) -- New combinations of medications and therapies, preceded by an old-fashioned chat between doctor and patient, could reduce the rates of nausea and vomiting following surgery.
That's the conclusion of an analysis of dozens of studies of postoperative nausea and vomiting (PONV), an unwelcome side effect of the anesthesia used during surgery.
Despite significant advances in the safety and side effects of anesthesia since the 1960s, study author Dr. Tong J. Gan says, roughly 30 percent of all surgical patients still experience nausea and vomiting after an operation.
Gan says that by identifying those at greatest risk of PONV before surgery, a combination of anti-nausea, anti-vomiting drugs and complementary therapies could shrink that percentage.
Gan, an associate professor of anesthesiology at Duke University Medical Center, says that could increase patient satisfaction, send people home faster and save on health-care expenses. His report appears in tomorrow's issue of the Journal of the American Medical Association.
Aside from the discomfort of PONV, Gan notes that, in some cases, repeated heaving and retching can interfere with wound healing and prolong a patient's hospital stay.
Gan says it's crucial for anesthesiologists to identify characteristics about people that put them at a higher risk for PONV. These include being female, being a nonsmoker, having a history of nausea and vomiting following surgery or a history of motion sickness, or having received opioids such as morphine as a painkiller.
"We know that women have three times the incidence of nausea and vomiting compared to men," Gan says. Although research has looked for hormonal explanations for this difference, the reasons are still not well understood.
The key to reducing the risk of PONV, Gan says, is for a patient and doctor to discuss potential risk factors before surgery. This may make her a candidate for anti-nausea or anti-vomiting medications.
"If they can communicate that with their anesthesiologist, that would certainly improve the chance of them not getting sick following surgery," says Gan, explaining the anesthesiologist might decide to give the patient preventive medications.
Drugs such as dexamethasone, ondansetron, droperidol, and scopolamine can be used alone or in combination to fight symptoms of nausea or vomiting, Gan says.
Another preventive approach that has gained ground in recent years is the use of a higher inhaled oxygen percentage during and after surgery. Room air is made up of about 20 percent oxygen, and patients are generally given a mixture containing about 30 percent oxygen during surgery.
However, some anesthesiologists have found success by giving patients a mix containing about 80 percent oxygen during surgery, sometimes continuing this for two hours after the operation.
Dr. Daniel I. Sessler, a professor of anesthesiology at the University of Louisville, has conducted several studies of this therapy's effect on reducing PONV.
It's suspected that during surgery, the flow of oxygen-rich blood to the intestinal tract is compromised, prompting the release of chemicals that are involved in nausea of vomiting.
"Giving extra oxygen will give the intestines enough oxygen even with low blood flow," Sessler says. "It's an attractive therapy in that it's risk-free and cost-free, and yet effective."
Along with the high-oxygen approach, Sessler says, there are other ways to reduce the risk of PONV, including choosing certain anesthetics over others.
Sessler says patients should also receive lots of fluids during surgery, and agrees that patients at high risk should receive preventive medications against nausea and vomiting.
At the same time, Gan says, there is a growing acceptance among anesthesiologists of complementary medicine techniques, including acupuncture and hypnosis, to treat PONV.
"Using a combination of techniques has been shown to be more effective than just using one single drug," says Gan, adding it starts with better communication between doctors and patients. "Eventually, it will help the patients to experience a better recovery if they communicate with their doctors and anesthesiologists about their risk factors."
Gan stresses that while the field of anesthesia has made huge strides in terms of safety, "we need to concentrate on how to improve the quality of postoperative recovery."
What To Do
Children pose a special problem. While kids under 2 have a low incidence of nausea and vomiting, Gan says common childhood procedures such as tonsillectomies have PONV rates of as high as 60 percent. Kids can check out the article What's Puke? from KidsHealth.org.
Read about PONV from Aventis or the Southern Medical Journal.
You can find more general information on nausea and vomiting from MedlinePlus.
