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“We can't always predict with certainty who will be affected by post-operative nausea and vomiting or how severe it will be,” says plastic surgeon and breast reconstruction specialist Dr. Constance M. Chen, “but we can identify factors that put some patients at higher risk and we can take steps before, during, and after surgery to prevent, minimize, and treat it.”
Nausea and vomiting are triggered in the brain, which receives signals via neurotransmitters – chemical messengers that transmit stimuli from various parts of the body to the brain. After surgery those stimuli might include pain, fear, and anxiety, or reactions to anesthetics and drugs such as opioids that are used to control pain. Dr. Chen says: “Our strategy for preventing or minimizing postoperative nausea and vomiting starts with assessing each patient's risk, trying to reduce those risk factors, administering one or more antiemetics (drugs that counter nausea and vomiting) depending on the patient's risk level, and treating postoperative nausea and vomiting if it does occur. Put briefly, we assess, prevent, and treat.”
Assessing risk for PONV
The risk of PONV for an individual patient varies widely as does the range of possible medications that might prevent it. To identify the best match between patient risk and preventive solution, a risk profile can be developed for each patient. Risk factors can be patient-related and anesthesia-related. The primary patient-related risk factors are gender (women are more susceptible to PONV than men); non-smoking status; and a prior incidence of PONV or susceptibility to motion sickness.
Risk factors associated with anesthesia include general anesthesia; inhalational vs. intravenous anesthesia; and longer periods of time under anesthesia. An additional factor is the administration of opioids during or after surgery to manage pain. “We can't change the patient-specific risk factors,” says Dr. Chen, “and surgical requirements may reduce the options for anesthesia and pain relief but we can take all these factors into account in determining a patient's risk and take preventive measures accordingly.”
Preventing PONV
The primary strategy for preventing PONV is avoiding narcotics and the administration of antiemetic medications. Different antiemetic drugs have different methods of action, that is, they act on different neurotransmitter receptors, so multiple antiemetics can be safely and effectively combined to improve the prophylactic effect. Among the commonly used antiemetics are anticholinergics, such as a scopolamine transdermal patch, which is applied several hours before surgery; a serotonin antagonist such as ondansetron (Zofran); and a neurokinin blocker such as aprepitant (Emend). Some antiemetics are long-lasting and are given only once; others can be repeated every six hours as needed.
“In patients at high risk for PONV, we try to reduce the use of opioids for post-operative pain management,” says Dr. Chen. “Acetaminophen, nonsteroidal anti-inflammatories (NSAIDs) and other non-opioid medications can effectively control pain in some cases and reduce the need for opioids, particularly in patients who have had previous reactions to them.”
Treating PONV
If post-operative nausea and vomiting do occur, it can be treated with a drug from a different class than the one that was given before surgery or with an additional dose of the original drug if it was effective but has worn off.
“Post-operative nausea and vomiting can be part of the pre-surgical consultation,” says Dr. Chen.” The anesthesia record from previous surgeries – whether successful in preventing PONV or not – can be invaluable to the surgeon and anesthesiologist in developing a postoperative nausea and vomiting risk profile and management strategy. We may not be able to eliminate postoperative nausea and vomiting entirely, but we have a wide range of options that can help us make every patient's surgery and recovery as comfortable as possible.”
Constance M. Chen, MD, is a board-certified plastic surgeon with special expertise in the use of innovative natural techniques to optimize medical and cosmetic outcomes for women undergoing breast reconstruction. She is Clinical Assistant Professor of Surgery (Plastic Surgery) at Weill Cornell Medical College and Clinical Assistant Professor of Surgery (Plastic Surgery) at Tulane University School of Medicine.
