Respiratory support with nasal high flow without supplemental oxygen in patients undergoing endoscopic retrograde cholangiopancreatography under moderate sedation: a prospective, randomized, single-center clinical trial

Abstract

Abstract BACKGROUND: Nasal high flow (NHF) may reduce hypoxia and hypercapnia during an endoscopic retrograde cholangiopancreatography (ERCP) procedure under sedation. The authors tested a hypothesis that NHF with room air during ERCP may prevent intraoperative hypercapnia and hypoxemia. METHODS: In the prospective, open-label, single-center, clinical trial, 75 patients undergoing ERCP performed with moderate sedation were randomized to receive NHF with room air (40 to 60 L/min, n = 37) or low-flow O2 via a nasal cannula (1 to 2 L/min, n = 38) during the procedure. Transcutaneous CO2, peripheral arterial O2 saturation, a dose of administered sedative and analgesics were measured. RESULTS: The primary outcome was the mean time-weighted total PtcCO2 of 47.2 mmHg in the NHF group and 48.2 mmHg in the LFO group, with no significant difference (-0.97, 95% CI -3.35 – 1.41, p = 0.421). In secondary outcome analysis, the duration of hypercapnia did not differ markedly between the two groups either [median (range) in the NHF group: 7 (0 – 99); median (range) in the LFO group: 14.5 (0 – 206); p = 0.313] and the occurrence of hypoxemia during an ERCP procedure under sedation was observed in 3 patients (8.1%) in the NHF group and 2 patients (5.3%) in the LFO group, with no significant difference (p = 0.674). CONCLUSIONS: Application of NHF with air did not reduce marked hypercapnia during ERCP under sedation relative to LFO. However, there was no significant difference in occurrence of hypoxemia between the two groups that indicates an improvement of gas exchanges by NHF. Trial registration jRCTs072190021 (https://jrct.niph.go.jp/en-latest-detail/jRCTs072190021) The full date of first registration on jRCT: 26/08/2019