Table 1 Schedule of patient enrollment, study interventions, and outcome measurements

Enrollment

 Inclusion criteria

 × 

 Exclusion criteria

 × 

 Written informed consent

 × 

 Baseline characteristics

 × 

 PONV risk score

 × 

 Randomization

 × 

 Allocation

 × 

Interventions

 Sequence 1: OFA-OBA

 × 

 Sequence 2: OBA-OFA

 × 

Endpoint measures

 Incidence of PONV

 × 

 × 

 × 

 Severity of PONV

 × 

 × 

 × 

 Antiemetic rescue therapy

 × 

 × 

 × 

 Postoperative pain scores

 × 

 × 

 × 

 The worst pain

 × 

 × 

 × 

 Need for rescue analgesia

 × 

 × 

 × 

 Level of sedation

 × 

 × 

 Hypotension

 × 

 × 

 Bradycardia

 × 

 × 

 Hypertension

 × 

 × 

 Tachycardia

 × 

 × 

 Hypoxemia

 × 

 × 

 × 

 Psychotomimetic/dissociative effects

 × 

 × 

 × 

 Time to extubation

 × 

 Length of PACU stay

 × 

Perioperative data

 Patient satisfaction

 × 

 In hospital major complications

 × 

 Length of anesthesia

 × 

 Length of procedure

 × 

 Postoperative length of hospital stay

 ×