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SAMBA issues new guidelines for PONV
Pediatrics and post-discharge addressed
Increased emphasis on patients at risk for postoperative nausea and vomiting (PONV), enhanced information on anesthesia for pediatric patients, and focus on post-discharge PONV are three significant changes in the Society for Ambulatory Anesthesia Guidelines for the Management of Postoperative Nausea and Vomiting.
Published in the December 2007 issue of Anesthesia & Analgesia, the guidelines update the 2003 guidelines, according to Tong J. Gan, MD, professor of anesthesiology at Duke University Medical Center in Durham, NC, and co-author of the guidelines. "The guidelines committee reviewed over 300 articles about PONV that have been published since we published the previous guidelines," he explains. "There has been a great deal of research, and we have learned a lot about PONV and side effects of different drugs in recent years."
The guidelines include an updated list of indicators of risk for PONV for adults and pediatric patients, says Gan. Risk factors for adults are female gender, nonsmoker, history of PONV, and use of postoperative opioids. Risk factors for pediatric patients are surgery lasting longer than 30 minutes, age older than 3, strabismus surgery, and history of POV or PONV in family members. "It's important to listen carefully to patients to identify these risks, especially previous history of PONV," he says. "Once you've identified the need for prophylactic treatment, don't just focus on one drug."
An algorithm for treatment of PONV identifies the various drugs available and how to determine dosage for adults and pediatric patients, he says. Specific information on pediatric medications is a significant addition to the new guidelines, Gan says. "In the 2003 guidelines, we did not talk specifically about pediatric patients, but with more pediatric surgeries occurring in the ambulatory setting, it is important to address this population," he says.
Determining proper dosage for children is difficult because clinical trials for medications are conducted with adults, so clinicians differ in their opinions on proper dosage for pediatric patients, Gan says. "Our guidelines include dosage recommendations based on the literature review we conducted," he says.
One key point made in the guidelines is the effectiveness of using a combination of antiemetic treatments as opposed to a single drug, says Gan. "One drug may not be enough, so the guidelines include a table that describes effective combination therapies," he says.
Another new section in the guidelines focuses on post-discharge nausea and vomiting, points out Gan. When patients at risk for PONV are identified and treated prophylactically, you still may see some nausea and vomiting in the recovery room, he says. "But, it is also important that we consider the nausea and vomiting that occur on the ride home, or even on Day 2 or Day 3," Gan says. "Evidence suggests that we should not use the same drugs after the patient has left the facility, so we identified different drugs that can help patients after the day of surgery." Transdermal scopolamine as well as orally disintegrating ondansetron tablets may provide a longer lasting antiemetic effect for patients who experience post-discharge nausea and vomiting, he adds.
In addition to identifying drugs that can prevent or treat PONV, the guidelines also suggest methods to reduce the baseline risk of PONV, says Gan. The strategies include: avoidance of general anesthesia by using regional anesthesia, use of propofol, avoidance of nitrous oxide, avoidance of volatile anesthetics, minimization of intraoperating and postoperative opioids, minimization of neostigmine, and adequate hydration. One item missing from the list of strategies to reduce the risk of PONV is the use of oxygen, he points out.
"We used to recommend that a high concentration of oxygen can be helpful in reducing PONV, but the scientific literature does not support that strategy," he says. "We no longer recommend this a way to minimize PONV."
There is a growing awareness of the need to minimize PONV, Gan says. "Although the medications to prophylactically treat PONV add to the cost of the case, it is very cost-effective for high-risk patients when you consider the cost of delayed discharge or admission to the hospital," he explains. "I believe that prophylactic treatments are more widely used, especially as costs of some drugs decrease."
The cost of Zofran dropped from $16 per dose to $1 per dose because the drug is now available as a generic, Gan says. Even with lower-cost drugs, don't use only the least expensive, he warns. "To keep PONV treatment cost-effective, it is still important not to rely only on one drug," Gan says. "The treatment won't be cost-effective if it doesn't work."
For more information or to obtain a copy of the Society for Ambulatory Anesthesia Guidelines for the Management of Postoperative Nausea and Vomiting, contact:
Postoperative and Post-discharge nausea and vomiting guidelines are also available from the American Society of PeriAnesthesia Nurses. To see the guidelines go to www.aspan.org, go to "clinical practice" on the top navigational bar and scroll down to "PONV/PDNV guidelines."