Effect of high‐flow vs. low‐flow nasal plus mouthguard oxygen therapy on hypoxaemia during sedation: a multicentre randomised controlled trial

Abstract

Whether high-flow vs. low-flow nasal oxygen reduces hypoxaemia for sedation during endoscopic retrograde cholangiopancreatography is currently unknown. In this multicentre trial, 132 patients ASA physical status 3 or higher, BMI > 30 kg.m -2 or with known or suspected obstructive sleep apnoea were randomly allocated to high-flow nasal oxygen up to 60 l.min -1 at 100% F I O 2 or low-flow nasal oxygen at 4 l.min -1 . The low-flow nasal oxygen group also received oxygen at 4 l.min -1 through an oxygenating mouthguard, totalling 8 l.min -1 . Primary outcome was hypoxaemia, defined as S p O 2 < 90% regardless of duration. Hypoxaemia occurred in 7.7% (5/65) of patients with high-flow and 9.1% (6/66) with low-flow nasal oxygen (percentage point difference À1.4%, 95%CI À10.9 to 8.0; p = 0.77). Between the groups, there were no significant differences in frequency of hypoxaemic episodes; lowest S p O 2 ; peak transcutaneous carbon dioxide; hypercarbia (transcutaneous carbon dioxide > 2.66 kPa from baseline); requirement of chin lift/jaw thrust; nasopharyngeal airway insertion; bag-mask ventilation; or tracheal intubation. Following adjustment for duration of the procedure, the primary outcome remained non-significant. In high-risk patients undergoing endoscopic retrograde cholangiopancreatography, oxygen therapy with high-flow nasal oxygen did not reduce the rate of hypoxaemia, hypercarbia or the need for airway interventions, compared with combined oral and nasal lowflow oxygen.

The effectiveness of high-flow nasal cannula during sedated digestive endoscopy: a systematic review and meta-analysis

“…Finally, the full texts of 14 articles were evaluated, and 7 studies were excluded: 1 was a pediatric patient study, 1 was a comment paper, 3 were protocols, 2 were observational studies. In total, 7 RCTs [ 21 – 24 , 26 – 28 ] were eligible in our meta-analysis, which ultimately included 2998 patients. The flowchart of the study is shown in Fig.…”

“…Trials took place across North America, Europe, Asia, and Australia. HFNC in two studies was used during ERCP procedural sedation [ 22 , 24 ], and others were used during esophagogastroduodenoscopy procedural sedation. In 3 of 7 articles, procedures were performed on high risk of hypoxemia subjects [ 23 , 24 , 28 ].…”

“…HFNC in two studies was used during ERCP procedural sedation [ 22 , 24 ], and others were used during esophagogastroduodenoscopy procedural sedation. In 3 of 7 articles, procedures were performed on high risk of hypoxemia subjects [ 23 , 24 , 28 ]. In the other four articles, sedation procedures were performed on low risk of hypoxemia subjects.…”

“…In the other four articles, sedation procedures were performed on low risk of hypoxemia subjects. All studies reported the primary outcome, and 6 of 7 studies reported the secondary outcome [ 21 – 24 , 26 , 28 ].…”

“…Because of its potential to improve oxygenation and ventilation, HFNC has been applied in many clinical situations to prevent hypoxemia, such as in awake fiber-optic intubation [ 19 ], conscious sedation during bronchoscopy and some dental treatments under intravenous sedation [ 16 , 20 ]. In addition, a few randomized controlled trials have shown that HFNC could also reduce the risk of hypoxemia during sedated digestive endoscopy [ 21 , 22 ], but some studies cannot draw the same conclusion [ 23 , 24 ].…”