A nurse administers an opioid analgesic to a postoperative client who also has severe obstructive sleep apnea (OSA). Which Intervention is most important for the nurse to implement before leaving the client alone?

A Elevate the head of the bed to a 45 degree angle. D Remove dentures or other oral appliance. C Apply the client's positive airway pressure device. B Lift and lock the side rails in place.