Abstract:Objective To evaluate the efficiency of ventilation through modified nasopharyngeal airway to prevent hypoxia during painless gastroscopy in patients with obstructive sleep apnea syndrome (OSAS).Methods 90 patients underwent painless gastroscopy were randomized divided into the following 3 groups: the supplementary oxygen via nasal cannula group (group C), the supplementary oxygen via modified nasopharyngeal airway group (group N) and the ventilation via modified nasopharyngeal airway group (group M). In the group C, O2 (5 L/min) was supplied via nasal cannula; In the group N, O2 (5 L/min) was supplied via modified nasopharyngeal airway; In the group M, ventilation was performed via a modified nasopharyngeal airway by connecting an anesthetic machine. The primary outcome of interest was the incidence of hypoxia. Secondary outcomes included subclinical respiratory depression, severe hypoxia, the necessary interventions (jaw lift, mask ventilation, and intubation) used to treat the adverse events, intreoperative and postoperative adverse events such as body movement, cough, pharyngalgia, xerostomia, nasal bleeding, and the satisfaction of the physician, anesthetist, and patient.Results Compared with the group C, the incidence of hypoxia was decreased in the group N (P < 0.05), the incidence of subclinical respiratory depression, the incidence of hypoxia, the requirement of jaw lift, and the incidence of cough were decreased in the group M, the satisfaction of the anesthetist and physician were significantly higher in the group M (P < 0.05). Compared with the group N, the incidence of hypoxia was decreased in the group M (P < 0.05). There were no significant difference in the incidence of body movement, nasal bleeding, pharyngalgia, and xerostomia among the 3 groups (P > 0.05).Conclusion The modified nasopharyngeal airway ventilation can effectively reduce the incidence of hypoxia during painless gastroscopy in patients with OSAS, with minimal related adverse events and good tolerance.