Postoperative vomiting in children (many children affected are unable to vocalize a feeling of nausea) is a common cause of morbidity after surgery. The incidence of vomiting after surgery is likely twice as high as it is in adults. Established factors that place a pediatric patient at risk for POV include patient age > 3 years, surgery > 30 min, type of procedure (i.e strabismus surgery and adenotonsillectomy), and history of POV. Due to the increased risk, there may be a greater need for prophylactic treatment in children. Drugs that have compelling evidence for their use in preventing POV in children include the 5-HT3 antagonists, Dexamethasone, and Droperidol.
The 5-HT3 antagonist, of which Ondansetron is the best studied (and most efficacious) are currently the best known prophylactic treatment for POV in children (NNT 2/3 for early/late POV respectively). Both the oral and IV forms are effective. The optimal dose is 0.1 – 0.15 mg/kg.
Dexamethasone has proven to be effective with a NNT of about 4. The optimal dose of dexamethasone is unknown (0.15 mg/kg is optimal according to Britian/Ireland)
Droperidol is also effective with a NNT of about 5. The optimal dose appears to be 50 – 70 mcg/kg, however, this dose is exceptionally high in children. The actual recommended dose is 10 – 15 mcg/kg for POV prevention.
Propofol at sub-hypnotic doses has also proven beneficial in preventing POV.
Combination therapy has proven to be more effective than monotherapy, especially in moderate to high risk children. The current recommendations are to give prophylactic doses of Ondansetron and Dexamethasone to all children at moderate to increased risk of POV unless contraindicated.
Reducing baseline risk factors is beneficial in preventing POV in children. Reducing baseline risk factors can be accomplished by utilizing regional anesthesia when available and avoidance of N2O, volatile anesthetics, adequate hydration and limiting opioids.
Gan et al. Consensus guidelines for the management of postoperative nausea and vomiting. Anesth. Analg.: 2014, 118(1);85-113
Anthony L Kovac Management of postoperative nausea and vomiting in children. Paediatr Drugs: 2007, 9(1);47-6