Table 2. Patient-, anesthesia-, and surgery-related risk factors for postoperative nausea and vomiting (PONV) in children.

Category	Risk in children (Eberhart classification) 29
Patient related	History of postoperative vomiting (POV) or PONV in relatives Age >3 years: it is rare in children <3 years old, increases with age over 3, and decreases again with puberty 29
Surgery related	Type of surgery: strabismus 30 Duration of surgery >30 minutes

The risk of POV for children with 0 to 1, 2, 3, or 4 of these risk factors is associated with an incidence of PONV of 10, 30, 50, and 70%, respectively. This scoring system has also been validated for children having surgery other than strabismus surgery; POV was observed in 3, 11, 30, and 40% of children who had 0, 1, 2 or 3 risk factors, respectively ³¹.