Abstract:Objective To investigate the clinical effect of nasal cannula combined with mask oxygen inhalation and transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) on painless colonoscopy in elderly patients.Methods 150 elderly patients aged 65 ~ 80, American Society of Anesthesiologists (ASA) were I to II, scheduled for painless colonoscopy, were enrolled and randomly assigned to three groups: nasal cannula group (group C), nasal cannula combined with mask group (groups M) and THRIVE group (group T), 50 patients in each group. Patients in three groups were given pure oxygen inhalation via nasal cannula, nasal cannula combined with face mask and THRIVE. Compare respiratory-related adverse events and intervention, incidence of adverse reactions, painless colonoscopy procedure and satisfaction of patients, anesthesiologists and endoscopist.Results The incidence of subclinical respiratory depression and hypoxia in group M and group T were lower than those in group C, the airway interventions such as jaw lift, increasing oxygen flow and mask ventilation in group M and group T were less than those in group C, the incidence of body movement in group M and group T was lower than that in group C, and the satisfaction of anesthesiologists and endoscopist in group M and group T were higher than those in group C (P < 0.05). There were no significant differences in respiratory-related adverse events, airway intervention measures and satisfaction score between group M and group T (P > 0.05).Conclusion Nasal cannula combined with mask oxygen inhalation as well as THRIVE could reduce respiratory related adverse events and airway intervention measures during painless colonoscopy in the elderly patients, reduce the occurrence of patients’ body movement, improve the satisfaction of anesthesiologists and endoscopist. The operation of nasal cannula combined with mask oxygen inhalation is convenient and can be used in clinic practice.