Fig. 2

Stacked bar charts showing the severity of PONV (A), PON (B), and POV (C) within 48 h postoperatively between the two groups. The severity of PONV was evaluated as follows: I = no nausea or vomiting, II = nausea but no vomiting, III = mild to moderate vomiting, and IV = severe and frequent vomiting more than five times within 24 h. The severity of PON was evaluated as follows: I = mild, II = moderate, III = severe. The severity of POV was evaluated as follows: I = no vomiting, II = vomiting episodes occurring 1–2 times within 24 h, III = vomiting episodes occurring 3–5 times within 24 h, IV = vomiting episodes occurring > 5 times within 24 h. PONV postoperative nausea and vomiting, PON postoperative nausea, POV postoperative vomiting