Abstract: Objective To observe the efficacy and safety of transnasal humidified rapid insufflation ventilatory exchange (THRIVE) in the elderly patients receiving painless gastroscopy combined with colonoscopy. Methods One hundred and twenty patients who need painless gastroscopy combined with colonoscopy, aged 65-79 years old, with an American Society of Anesthesiologists physical status of Ⅰ-Ⅲ, with body mass index of 18-28, with a Mallampatti of Ⅰ or Ⅱ, were divided into two groups (n=60) using a random number table method, nasal catheter oxygen inhalation group (group C) and THRIVE group (group T). The adverse reactions and treatments related to hypoxia during operation were recorded according to the procedure of Society of Intravenous Anaesthesia (SIVA). The other adverse events including involuntary limbs swing, choking cough, vomiting, airway injury and air pressure injury were recorded as well. The levels of the hemodynamic index of the patients before anesthesia (T₀), after insertion of the gastroscope (T₁), and at the time of awaking (T₂) were recorded. The operation time, recovery time, total dose of propofol and remifentanil, satisfaction of the anesthesiologists, operators and the patients were recorded after the operation. Results Compared with group C, the incidence rates of SpO₂<95%, jaw-lift, pressured mask, inserted asopharyngeal airway and involuntary limbs swing in group T were significantly decreased(P<0.05), and the dosage of propofol was increased (P<0.05), and the satisfaction of the anesthesiologists, operators and the patients was significantly improved (P<0.05).The levels of hemodynamic index, the dose of remifentanil, the operation and recovery time showed no significant differences between the two groups (P>0.05). No patients presented with airway injury or air pressure injury in both groups. Conclusions THRIVE can maintain the oxygenation in the elderly patients receiving painless gastroscopy combined with colonoscopy more safely and effectively, reducing the incidence of the involuntary limbs swing and improving the satisfaction of the doctors and patients.

Key words: transnasal humidified rapid insufflation ventilatory exchange, gastroscopy, colonoscopy, aged