medwireNews: Oxygenation via a high flow nasal cannula (HFNC) significantly reduces the incidence of hypoxia during sedated gastrointestinal (GI) endoscopy in patients with obesity without increasing adverse events, researchers say.
“With the increase in obesity rates, a device that can reduce airway adverse events is clinically relevant,” write Diansan Su (Shanghai Jiaotong University School of Medicine, China) and colleagues in The BMJ.
The researchers undertook the trial in 984 patients to validate the benefits of HFNC for individuals with obesity, for whom evidence around the use of HFNC in GI endoscopy has been scarce, they say.
The investigators enrolled adults aged from 18 to 70 years with a BMI of 28 kg/m2 or more, and an American Society of Anesthesiologists (ASA) class of I or II, representing healthy patients and those with a mild systemic disease, respectively. The participants were scheduled to undergo sedated GI endoscopy including gastroenteroscopy, gastroscopy, and colonoscopy.
The patients were given oxygen through a nasal cannula at a rate of 3 L/min before being sedated with 0.5 mg/kg propofol. After this, the group using an HFNC received oxygen at a flow rate of 60 L/min at 37°C and an oxygen concentration of 100%, while the control group received oxygen at a flow rate of 6 L/min via a standard nasal cannula. Patients undergoing gastroscopy or colonoscopy, and gastroenteroscopy received sufentanil 5.0 µg and 7.5 µg, respectively, before receiving intravenous propofol 1–2 mg/kg. The patients were kept sedated throughout the procedure with intermittent propofol given at a dose of 0.2–0.5 mg/kg.
During the procedure, the investigators recorded incidences of hypoxia, which were classified as having an arterial oxygen saturation (SpO₂) of between 75% and 90% for under 60 seconds. They also measured how many patients had subclinical respiratory depression (SpO₂ 90–95% for any duration), severe hypoxia (SpO₂ 75–90% ≥60 seconds), and other adverse events including xeromycteria, rhinalgia, pharyngalgia, headache, and barotrauma.
The patients were a mean of 49.2 years old, 63.1% were men, and 79.1% were classified as ASA II, with 54.7%, 26.4%, and 18.9% undergoing gastroenteroscopy, gastroscopy, and colonoscopy, respectively.
Baseline characteristics were balanced across the HFNC and control groups, including BMI (30.1 vs 29.9 kg/m2), mean pre-anesthesia SpO₂ (97.8 vs 97.8%), surgery time (10.9 vs 10.4 mins), snore mentioned by family (89.9 vs 90.6%), and having a high probability of obstructive sleep apnea based on the STOP-Bang score (73.6 vs 71.9%). The HFNC group received significantly more propofol than the control group, with corresponding totals of 184.0 mg versus 174.0 mg for actual body weight.
HFNC oxygenation significantly reduced hypoxia with an incidence of 2.0% of patients versus 21.2% in the control group, and a risk ratio of 0.10 in favor of HFNC. It also led to significantly fewer incidences of subclinical respiratory depression (5.6 vs 36.3%; risk ratio=0.16), and severe hypoxia (0.0 vs 4.1%).
Su et al write that the data “show that HFNC oxygenation can completely eliminate the occurrence of severe hypoxia in patients with obesity but not the occurrence of hypoxia and subclinical respiratory depression.”
Nonetheless, the authors note that hypoxia was easier to correct for patients receiving HFNC, with none requiring mask ventilation and only 2.2% needing a jaw thrust maneuver compared with 4.9% and 21.1% of controls, respectively.
Su and colleagues also observed a similar rate of adverse events (AEs) among HFNC patients and controls, such as bradycardia, tachycardia, and hypotension, with the AEs being mild and infrequent. The most common AE among the HFNC group after awakening was xeromycteria in 2.8% of the patients.
The benefits of HFNC held up when analyzing different subgroups, including by BMI, surgery type, STOP-Bang score, and propofol dose, “indicating that the benefits of HFNC were consistent in different clinical settings,” the researchers say.
In an editorial related to the study, Michele Carron, from the University of Padua in Italy, and Enrico Tamburini, from Padua University Hospital in Italy, say that the trial “marks a pivotal step in managing respiratory risks in patients with obesity during sedated gastrointestinal endoscopy.”
On the other hand, they point out that cost concerns limit the adoption of HFNC and that “[p]olicy makers must balance costs with benefits in reducing complications and improving outcomes in high risk groups.”
They conclude: “Integrating high flow nasal oxygenation into practice will require global collaboration among clinicians, educators, and policy makers to ensure that its potential is fully realized across diverse healthcare settings.”
medwireNews is an independent medical news service provided by Springer Healthcare Ltd. © 2025 Springer Healthcare Ltd, part of the Springer Nature Group