Obstructive sleep apnea (OSA) is defined as the absence of air flow for more than ten seconds occurring more than 30 times during 7 hours of sleep despite continuing ventilatory efforts with associated decrease in arterial oxygen saturation for more than 4% from base line of the patient. The association between sleep and anesthesia has clinical importance; the presence of obstructive sleep apnea syndrome indicates a predisposition to upper airway obstruction under the influence of anesthetic or analgesic effect.A polysomnogram or sleep study is a comprehensive study used to diagnose a wide spectrum of sleep disorders. It is the "gold standard" in the evaluation and diagnosis of obstructive sleep apnea syndrome.CPAP remains the mainstay of positive pressure therapy for obstructive sleep apnea