A healthy 30-year-old female undergoes an uneventful, elective ventral hernia repair under general anesthesia. She goes to the surgical floor, where she receives a hydromorphone PCA for pain control and is kept NPO until return of bowel function. She does well until postoperative day 2, when she develops nausea and vomiting. Her nurse calls you asking what to do. You evaluate the patient. When you arrive at her bedside, you find her sitting up in bed leaning over an emesis bin. She tells you she has been vomiting intermittently for the past 2 hours. Her incision looks benign and her abdomen is not distended. She has infrequent bowel sounds.
1. What is the best medication to give her to help with her symptoms?
2. Is this patient’s nausea and vomiting likely due to the lingering effects of anesthesia?
Postoperative Nausea and Vomiting
There are 3 types of afferent nerve inputs that ultimately result in vomiting—input from the vestibular complex, input from the viscera, and input from the chemoreceptor trigger zone in the base of the fourth ventricle. Numerous neurotransmitters are involved in these pathways, although dopamine and serotonin are the most clinically relevant. This is because visceral stimulation and stimulation of the chemoreceptor trigger zone are the most likely causes of nausea in postsurgical patients, both of which are mediated by these 2 neurotransmitters. This helps to explain why the most frequently used antiemetics following surgery target dopamine and serotonin.
Metoclopramide (Reglan) and promethazine (Phenergan) are the most common dopamine antagonists. Promethazine is especially useful as it is available in both suppository and intravenous forms. Unfortunately, this entire class of medications may cause significant side effects, including orthostatic hypotension and excessive sedation. They can also cause extrapyramidal effects and are therefore strictly contraindicated in patients with Parkinson disease. In addition, promethazine can cause venous sclerosis at the site of administration, while metoclopramide has promotility effects and should not be given to patients with either confirmed or suspected bowel obstruction.
Due to their better side effect profiles, serotonin antagonists have become the primary treatment for a variety of causes of nausea. While side effects of serotonin antagonists are rare, they include headache, diarrhea, hypersensitivity reactions, and QT prolongation. The most common drug in this class is ondansetron (Zofran), which would be an appropriate first-line medical treatment for the case presented.
Nausea and vomiting are not uncommon in the postoperative period. Nausea and vomiting in the first 24 hours after surgery is defined as “early” postoperative nausea and vomiting (PONV), and is usually directly related to the effects of anesthesia. Early PONV occurs in 20% to 30% of patients, is more common in females, and is the number 1 reason for unexpected hospital admission following ambulatory surgery. Early PONV can often be prevented with appropriate chemoprophylaxis in people at high risk for ...