Published: Mar. 12, 2002
Updated: Nov. 3, 2004
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By Duke Medicine News and Communications
DURHAM, N.C. -- A Duke University Medical Center anesthesiologist who analyzed studies of postoperative nausea and vomiting (PONV) believes that better communication between physicians and patients would significantly reduce nausea and vomiting as a side effect of surgery.
He advocates that physicians work with each patient to develop a plan to reduce PONV that might include treatments ranging from anti-emetic drugs to stress reduction to acupuncture. Not only would the use of such plans return patients to their everyday lives sooner, he said, it could also significantly reduce health care costs.
Despite decades of advances in surgical technique and improved anesthetic agents, one out of three patients will still experience nausea and vomiting after surgery. Such a condition not only influences patient satisfaction, but can also prolong recovery, lengthen hospital stays and negatively impact the surgery itself.
"There are more than 35 million surgical procedures performed each year in the U.S., so PONV is an extremely important health care issue," said Duke anesthesiologist Dr. Tong J. Gan, whose analysis was published in the March 13, 2002 issue of the Journal of the American Medical Association. "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.
"We already know a lot about PONV and new drugs are being developed all the time. It is just a matter of putting it all together," Gan continued. "To do better, physicians need to ask the right questions of their patients in order to develop strategies to reduce the chances of it occurring."
The challenge, according to Gan, is identifying all relevant the risk factors ? whether they be patient characteristics, type of surgery, and method of anesthesia ? that place the patient at higher risk for PONV. With this knowledge, steps can then be taken to make a postoperative recovery as painless and event-free as possible.
According to Gan, four main patient characteristics appear to predispose patients to PONV: being female, being young, being a non-smoker and having a history of PONV or motion sickness. Additionally, the chance of PONV increases significantly if opioids are used for postoperative pain management.
"Women are at a three times higher risk of PONV when compared to men," Gan explained. "There have been studies looking at hormonal links or where a woman may be in her menstrual cycle at the time of surgery. But nothing to date is conclusive."
In general terms, the likelihood of developing PONV decreases with age, and studies during the past five years have shown that smokers have a lower risk for PONV, though the mechanism of this protection is not well understood, Gan said.
According to Gan, patients with none of the above patient risk factors have a 10 percent chance of PONV, while patients with all risk factors have a 79 percent chance.
On the surgical side, there are certain procedures that are known for producing a high incidence of PONV, including certain neurosurgical procedures, major breast procedures, certain eye surgeries, otolaryngologic (ear, nose, throat) operations, laparoscopy and laparotomy.
Interestingly, he said, the minimally invasive procedures such as laparoscopy have high rates of PONV. This could be due to the gas, which is used to "inflate" the abdomen to create a workspace for the instruments, putting pressure on the vagus nerve, which has a connection to the brain's nausea and vomiting center.
"By assessing all these potential risk factors ? both from the patient and the surgical sides ? we can tailor a plan to reduce the incidence of PONV," Gan said. "It takes input from the patient and all members of the medical team."
According to Gan's analysis, patients with one or two of the combined risk factors are considered at mid- to moderate-risk, and a single dose of an anti-emetic drug (anti-nausea) such as droperidol, scopolamine or dexamethasone can be effective. Those with more than four factors should be considered at high risk and should receive a combination of anti-emetics and should probably receive total intravenous anesthesia for their procedure.
In addition to these approaches to preventing PONV, Gan said there are additional options that should be considered, ranging from the delivery of additional oxygen during surgery to maintaining proper hydration during surgery to reducing stress before surgery through the use of medication.
Another complimentary approach includes the use of acupuncture before and during surgery. A recent study conducted by Gan demonstrated that this ancient Chinese practice was just as effective in controlling PONV for women undergoing major breast surgery as anti-emetics. These procedures cause PONV in about 70 percent of the cases.
"Anesthesia is very safe now and we need to move beyond the surgery itself to improving the quality of recovery," Gan said. "The aim is not just to ensure our patients survive a surgical procedure, but to get our patients back to their normal everyday lives quicker."