Anuj Malhotra, M.D. (left), emphasizes a point during the PBLD discussion Sunday.
All surgical patients are at risk for postoperative and post-discharge nausea and vomiting (PDNV). Physician anesthesiologists have a wide range of interventions to minimize nausea and vomiting, but many prolong the QT interval.
“The reality is that most of our PDNV agents carry a QT interval warning,” said Anuj Malhotra, M.D., Assistant Professor of Anesthesiology at Mount Sinai Hospital. “But for most agents and most patients, those warnings apply to much higher doses than we typically use to control nausea and vomiting. You can manage the issue by stratifying your patients by their risk of nausea and vomiting, and selecting your drugs appropriately.”
Dr. Malhotra was one of 11 leaders for a Problem-Based Learning Discussion (PBLD) session Sunday. Other topics included blood and fluid replacement, lessons from and impact of the TAVR experience, the anesthesiologist as a second victim of an adverse patient care event, intubation during anesthesia for ERCP, postop pain management in patients on buprenorphine maintenance therapy and regional versus general anesthesia for very elderly patients.
Every patient has a baseline risk of about 10 percent for PDNV, Dr. Malhotra said, and most anti-nausea and antiemetic agents reduce risk by about 20 percent. But that 20 percent risk is cumulative, not additive. If a patient has an 80 percent risk of PDNV, the first agent reduces that risk to 60 percent. The second agent reduces risk another 20 percent to 48 percent, the third agent another 20 percent to 38 percent, and so on.
In addition to declining effects on risk reduction, every additional drug adds new side effects.
“You already know the risk of nausea and vomiting for any particular patient,” he said. “And you want to avoid treatment approaches that add hidden risk. The fewer drugs you can get away with, the better, and it can help to reduce risk factors such as postop opioid use whenever possible. We all have a few favorite drugs, but there are alternatives that you might not think of.”
Dexamethasone remains the most common agent to reduce PDNV, but it is slow to act and is not a useful rescue agent. It carries an increased risk for bleeding and infection, particularly at higher doses, but that risk is offset by its efficacy in preventing nausea and vomiting. Preventing vomiting can be particularly important for patients with oral surgery or fragile suture lines.
Because postop opioids can dramatically increase the risk of PDNV, reducing or eliminating opioid use can reduce risk. For some patients and procedures, a regional block may be a good alternative. Many patients, including children, can be discharged on a regional block with a pump and catheter already in place to maintain the block for several days.
Another alternative is gabapentin or pregabalin. Either drug can be taken the night before surgery to reduce postop pain and reduce the need for opioids. Gabapentin requires a large dose, Dr. Malhotra said, usually 600-800 mg. Pregabalin doses are in the range of 100-150 mg for most patients.
Acupoint electrical stimulation also can reduce postop pain as well as PDNV. Gentle stimulation is usually applied to point P6, located on each wrist near the radial artery. Acupoint stimulation can be particularly useful for patients who are hesitant to use pharmacologic agents or claim allergies.
Simply talking to patients about postop pain, nausea and vomiting can also make a difference.
“Anticipation of nausea, vomiting or pain, or all three, is a powerful risk factor,” Dr. Malhotra said. “The more strongly a patient believes the treatment you are proposing is going to work, the more likely it will succeed.”
