Hypoxia is one of the most frequent adverse events with sedated GI endoscopy and can lead to serious consequences. No modalities have been found previously to prevent hypoxia. High-flow nasal cannula (HFNC) supportive oxygen therapy provides heated and humidified oxygen up to 60 L/minute. Because of its ability to improve respiratory function and good tolerance, we aimed to evaluate the validity and safety of HFNC supportive oxygen therapy in preventing the incidence of hypoxia in patients undergoing gastroscopy with propofol sedation.

In a multicenter, prospective randomized single-blinded study, 1994 outpatients undergoing routine gastroscopy with propofol sedation provided by an anesthesiologist were randomized into 2 groups: the nasal cannula group (O₂ [2 L/minute] was supplied via an HFNC) and the HFNC group (O₂ [30-60 L/minute] was supplied via an HFNC) at 3 centers from November 2017 to February 2018. The primary outcome was the incidence of hypoxia. Other adverse events were also recorded.

HFNC supportive oxygen therapy decreased the incidence of hypoxia (75% ≤ Spo₂ < 90% for <60 seconds) and severe hypoxia (Spo₂ < 75% for any duration or 75% ≤ Spo₂ < 90% for ≥60 seconds) from 8.4% to 0% (P < .001) and from 0.6% to 0% (P = .03), respectively. The only HFNC-related adverse event was xeromycteria/rhinalgia (1.7%), which was observed 1 minute after the procedure and disappeared after 30 minutes.

HFNC supportive oxygen therapy can prevent the incidence of hypoxia and severe hypoxia in patients in America Society of Anesthesiologists class I-II undergoing elective gastroscopy under propofol sedation, with minimal related adverse events and good tolerance. (Clinical trial registration number: NCT03332433.)