ABSTRACT: Bronchoscopy is a procedure for diagnosis and treatment decision-making in patients with lung disease, especially those with acute respiratory failure. However, the optimal bronchoscopic method for patients with acute respiratory failure is not known. Therefore, in the real world, we sometimes hesitate to perform bronchoscopy in such patients because of safety and have experienced treating patients without bronchoscopy. To address this problem, we evaluated the usefulness and safety of Jackson mask ventilation, a novel noninvasive method of bronchoscopy performed under mask ventilation using the Jackson Rees circuit, in patients with acute respiratory failure.We retrospectively reviewed patients with acute respiratory failure who underwent bronchoscopy at our institution between January 2015 and May 2018. We compared patients who received Jackson mask ventilation (Jackson group) and those who received conventional oxygen administration (conventional group). Mean percutaneous oxygen saturation (SpO2) and mean oxygen flow rate were compared between the groups by the Wilcoxon signed-rank test. We excluded patients who were intubated and those without acute respiratory failure who received Jackson mask ventilation preventively.Of 1262 patients who underwent bronchoscopy, 12 were classified into the Jackson group and 13 into the conventional group. Proper oxygenation was maintained in the Jackson group, with SpO2 increasing after Jackson mask ventilation (89.4% to 96.8%, P = .03). Mean SpO2 was significantly higher in the Jackson group than in the conventional group (96.8% vs 95.2%, P = .03). Mean oxygen flow rate was significantly lower in the Jackson group (4.0 L/min vs 7.9 L/min, P < .001). There was no significant difference in safety.Our findings suggest that Jackson mask ventilation is safe and effective when performing bronchoscopy in patients with acute respiratory failure. Jackson mask ventilation maintained proper oxygenation and decreased the oxygen flow rate compared with the conventional method. Using Jackson mask ventilation, we could perform bronchoscopy safely and effectively in patients with acute respiratory failure, including some who had unstable respiratory status. (UMIN000038481).