Randomization and allocation concealment
OSA, pain
Patients with OSA (defined as AHI > 5 events/hr), were randomized into two groups: Control or Intervention groups (computer generated blocks of 8) by the research analyst, who was not involved in group allocation or data collection during the study. Group allocation was concealed using sealed, opaque envelops, and patients were assigned to their group following surgery. In the Control group (Group C), there was no bed elevation, and patients were positioned at bedtime with no head elevation or bed angle to zero degrees from the horizontal. In the Intervention group (Group I), patients were positioned at bedtime in a semi-upright position with bed elevated to 30 to 45 degrees from horizontal. The bed angle was measured by a research assistant using an in-built bed angle monitor, or a goniometer, wherever applicable. The bed angle measurements were performed at night and in the morning to monitor compliance with the allocated bed position. Patients had the option to request changing the bed angle to facilitate recovery from surgery in view of pain and discomfort.