High-Flow Nasal Oxygen and Desaturation During Deep Sedation for Colonoscopy in Patients at Increased Respiratory Risk: A Propensity Score-Matched Cohort Study
6 affiliations
- 1Critical Care Department, Hospital Universitario del Tajo, 28300 Aranjuez, Spain
- 2Facultad de Ciencias Biomédicas y de la Salud, Universidad Alfonso X el Sabio, 28692 Villanueva de la Cañada, Spain
- 3Fundación para la Investigación Biomédica e Innovación, Hospital Universitario Infanta Sofía, Hospital Universitario del Henares y Hospital Universitario del Tajo, 28702 San Sebastián de los Reyes, Spain
- 4Critical Care Department, Hospital General Universitario Gregorio Marañón, 28030 Madrid, Spain
- 5Facultad de Medicina, Universidad Complutense de Madrid, 28040 Madrid, Spain
- 6Gastroenterology Department, Hospital Universitario del Tajo, 28300 Aranjuez, Spain
Abstract
Background/Objectives: Hypoxaemia is the most common adverse event during procedural sedation. High-flow nasal oxygen (HFNO) may reduce desaturation through continuous positive airway pressure, anatomical dead space washout, and stable FiO2 delivery. This retrospective cohort study assessed the association between two oxygen delivery strategies—HFNO versus Venturi mask oxygen—and the incidence of desaturation (SpO2 <90% at any time) during deep sedation for colonoscopy in patients at increased respiratory risk. The two strategies differed simultaneously in flow rate, delivered FiO2 (0.50 vs. 0.40), device interface, and humidification; any observed difference cannot be attributed exclusively to the high-flow mechanism. Methods: A single-centre retrospective cohort study with propensity score matching (PSM) was performed, including 200 consecutive adult patients with established obstructive sleep apnoea (OSA) or high-risk STOP-BANG criteria undergoing deep sedation for colonoscopy, grouped by oxygen delivery strategy: HFNO via nasal cannula (50 L/min, FiO2 0.50) versus Venturi mask (12 L/min, FiO2 0.40). The estimand of interest was the average treatment effect on the treated (ATT). Results: After 1:1 nearest-neighbour PSM (calliper 0.2 SD of the logit propensity score), 71 matched pairs were obtained; 10 of 17 covariates achieved adequate balance (SMD < 0.10). In the matched cohort, desaturation occurred in 12.7% of HFNO patients versus 22.5% of controls (matched-pair OR 0.53, 95% CI 0.23–1.23; p = 0.211; McNemar test), an absolute risk difference of 9.8 percentage points (95% CI −1.5 to +21.1). The estimate was imprecise and the confidence interval included no association. A sensitivity analysis using conditional logistic regression yielded an adjusted OR of 0.52 (95% CI 0.22–1.21; p = 0.129). The sample provided only 30.8% statistical power; an estimated 474 total patients (237 per group, parallel group design) would be required for 80% power in a future confirmatory randomised trial. Conclusions: In this propensity-matched cohort, the observed desaturation rate was lower with HFNO than with Venturi mask oxygen, but the estimate was imprecise, the confidence interval included no association, and residual confounding precludes definitive conclusions. These findings are hypothesis-generating and should be evaluated in a prospectively designed, adequately powered randomised trial.
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BibTeX
@article{alonsofernandez2026highflow,
title = {{High-Flow Nasal Oxygen and Desaturation During Deep Sedation for Colonoscopy in Patients at Increased Respiratory Risk: A Propensity Score-Matched Cohort Study}},
author = {M. Ángeles Alonso-Fernández and Óscar Martínez-González and Mónica García-Alonso and Carmen Martín-Parra and Susana Soto-Fernández and Blanca López-Matamala and Elena Marín-Alcolado and Madian Manso-Álvarez and M. José Pérez-Grueso and Miriam Chana-García and María de Lucas-Gallego and Rafael Blancas},
journal = {Journal of Clinical Medicine},
year = {2026},
month = oct,
doi = {10.3390/jcm15218254},
url = {https://www.mdpi.com/2077-0383/15/21/8254},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - High-Flow Nasal Oxygen and Desaturation During Deep Sedation for Colonoscopy in Patients at Increased Respiratory Risk: A Propensity Score-Matched Cohort Study
AU - M. Ángeles Alonso-Fernández
AU - Óscar Martínez-González
AU - Mónica García-Alonso
AU - Carmen Martín-Parra
AU - Susana Soto-Fernández
AU - Blanca López-Matamala
AU - Elena Marín-Alcolado
AU - Madian Manso-Álvarez
AU - M. José Pérez-Grueso
AU - Miriam Chana-García
AU - María de Lucas-Gallego
AU - Rafael Blancas
PY - 2026
DA - 2026/10/23
JO - Journal of Clinical Medicine
DO - 10.3390/jcm15218254
UR - https://www.mdpi.com/2077-0383/15/21/8254
AB - Background/Objectives: Hypoxaemia is the most common adverse event during procedural sedation. High-flow nasal oxygen (HFNO) may reduce desaturation through continuous positive airway pressure, anatomical dead space washout, and stable FiO2 delivery. This retrospective cohort study assessed the association between two oxygen delivery strategies—HFNO versus Venturi mask oxygen—and the incidence of desaturation (SpO2 <90% at any time) during deep sedation for colonoscopy in patients at increased respiratory risk. The two strategies differed simultaneously in flow rate, delivered FiO2 (0.50 vs. 0.40), device interface, and humidification; any observed difference cannot be attributed exclusively to the high-flow mechanism. Methods: A single-centre retrospective cohort study with propensity score matching (PSM) was performed, including 200 consecutive adult patients with established obstructive sleep apnoea (OSA) or high-risk STOP-BANG criteria undergoing deep sedation for colonoscopy, grouped by oxygen delivery strategy: HFNO via nasal cannula (50 L/min, FiO2 0.50) versus Venturi mask (12 L/min, FiO2 0.40). The estimand of interest was the average treatment effect on the treated (ATT). Results: After 1:1 nearest-neighbour PSM (calliper 0.2 SD of the logit propensity score), 71 matched pairs were obtained; 10 of 17 covariates achieved adequate balance (SMD < 0.10). In the matched cohort, desaturation occurred in 12.7% of HFNO patients versus 22.5% of controls (matched-pair OR 0.53, 95% CI 0.23–1.23; p = 0.211; McNemar test), an absolute risk difference of 9.8 percentage points (95% CI −1.5 to +21.1). The estimate was imprecise and the confidence interval included no association. A sensitivity analysis using conditional logistic regression yielded an adjusted OR of 0.52 (95% CI 0.22–1.21; p = 0.129). The sample provided only 30.8% statistical power; an estimated 474 total patients (237 per group, parallel group design) would be required for 80% power in a future confirmatory randomised trial. Conclusions: In this propensity-matched cohort, the observed desaturation rate was lower with HFNO than with Venturi mask oxygen, but the estimate was imprecise, the confidence interval included no association, and residual confounding precludes definitive conclusions. These findings are hypothesis-generating and should be evaluated in a prospectively designed, adequately powered randomised trial.
SN - 2077-0383
ER -