Fig. 2.

The incidence distribution of PONV in both groups. Dual group: ketorolac and fentanyl delivered by a dual-chamber PCA, Single group: fentanyl alone delievered by a PCA. PACU: post-anesthesia care unit, PONV: postoperative nausea and vomiting, PCA: patient-controlled analgesia, NA: not available. ^*Five patients in the single group discontinued the intravenous PCA at postoperative 2–6 h. ^†Two patients in the dual group and 13 patients in the single group discontinued the intravenous PCA at postoperative 6–12 h.