Postoperative Nausea and Vomiting.
Postoperative nausea and vomiting (PONV ) is the result of multiple of perioperative factors such as fasting, autonomic imbalance, pain, and anesthetic effects on chemotactic centers.
The emetic centers are located in the lateral reticular formation of the medulla.
Patients who have a higher risk of developing PONV should receive double- or triple-agent prophylaxis. Prophylaxis in patients at very low risk may not be indicated.
Regional anesthesia techniques reduce the incidence of PONV significantly. When a general anesthetic is required, limited use of narcotics, volatile anesthetics, and nitrous oxide may be possible with a total intravenous anesthetic technique.
- Increase FiO2 to ensure adequate oxygenation.
- Adequate hydration with intravenous crystalloids.
- Ondansetron 4 mg IV.
- Metoclopramide 25–50 mg. Metoclopramide use has been associated with extrapyramidal and sedative side-effects.
In case of refractory nausea:
- Phenothiazines (promethazine 25 mg IV or prochlorperazine 10 mg IV)
- Droperidol (0.625 mg IV) is highly effective (warning for QTc prolongation)
- Propofol (10–20 mg).
- At low doses, dexamethasone is not only effective against PONV but also against post-surgical pain and fatigue.
Risk Factors:
