Clinical outcomes, safety, and potential prognostic factors of noninvasive respiratory support in patients with COVID-19: A Japanese multicenter observational study

Jiro Ito; Toshiki Yokoyama; Aiko Tanaka; Ryutaro Seo; Keisuke Tomii; Clara So; Shinyu Izumi; Yutaka Kozu; Kazuo Chin; Yasuhiro Gon; Naoki Nishimura; Hajime Sasano; Kazuko Yamamoto; Yuichiro Takeshita; Eriko Hamada; Motoo Yamauchi; Tetsuhisa Kitamura; Yuji Fujino; Yasuhiro Kondoh

doi:10.1016/j.resinv.2025.06.013

Clinical outcomes, safety, and potential prognostic factors of noninvasive respiratory support in patients with COVID-19: A Japanese multicenter observational study

Respir Investig. 2025 Jun 30;63(5):794-799. doi: 10.1016/j.resinv.2025.06.013. Online ahead of print.

Authors

Jiro Ito¹, Toshiki Yokoyama², Aiko Tanaka³, Ryutaro Seo⁴, Keisuke Tomii⁵, Clara So⁶, Shinyu Izumi⁶, Yutaka Kozu⁷, Kazuo Chin⁸, Yasuhiro Gon⁷, Naoki Nishimura⁹, Hajime Sasano², Kazuko Yamamoto¹⁰, Yuichiro Takeshita¹¹, Eriko Hamada¹², Motoo Yamauchi¹³, Tetsuhisa Kitamura¹⁴, Yuji Fujino¹⁵, Yasuhiro Kondoh¹⁶

Affiliations

¹ Department of Anesthesiology and Critical Care Medicine, Kobe City Medical Center General Hospital, 2-1-1 Minatojima-Minamimachi, Chuo-ku, Kobe, Hyogo, 650-0047, Japan.
² Department of Respiratory Medicine and Allergy, Tosei General Hospital, 160 Nishioiwake-cho, Seto, Aichi, 489-8642, Japan.
³ Department of Anesthesiology and Intensive Care Medicine, Osaka University Graduate School of Medicine, 2-15 Yamadaoka, Suita, Osaka, 565-0871, Japan; Department of Intensive Care, University of Fukui Hospital, 23-3 Matsuoka Shimoaizuki, Eiheiji-cho, Yoshida-gun, Fukui, 910-1193, Japan.
⁴ Department of Emergency Medicine, Kobe City Medical Center General Hospital, 2-1-1 Minatojima-Minamimachi, Chuo-ku, Kobe, Hyogo, 650-0047, Japan.
⁵ Department of Respiratory Medicine, Kobe City Medical Center General Hospital, 2-1-1 Minatojima-Minamimachi, Chuo-ku, Kobe, Hyogo, 650-0047, Japan.
⁶ Department of Respiratory Medicine, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo, 162-8655, Japan.
⁷ Division of Respiratory Medicine, Nihon University School of Medicine, 30-1 Ohyaguchi-Kamicho, Itabashi-ku, Tokyo, 173-8610, Japan.
⁸ Department of Sleep Medicine and Respiratory Care, Division of Sleep Medicine, Nihon University of Medicine, 30-1 Ohyaguchi-Kamicho, Itabashi-ku, Tokyo, 173-8610, Japan.
⁹ Department of Pulmonary Medicine, Thoracic Center, St. Luke's International Hospital, 9-1 Akashi-cho, Chuo-ku, Tokyo, 104-8560, Japan.
¹⁰ Division of Infectious, Respiratory, and Digestive Medicine, University of the Ryukyus Graduate School of Medicine, 207 Uehara, Nishihara, Nakagami-gun, Okinawa, 903-0215, Japan.
¹¹ Department of Pulmonary Medicine, International University of Health and Welfare, Narita Hospitall, 852 Hatakeda, Narita, Chiba, 286-0124, Japan.
¹² Department of Respiratory Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan.
¹³ Department of Respiratory Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan; Department of Clinical Pathophysiology of Nursing, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8522, Japan.
¹⁴ Division of Environmental Medicine and Population Sciences, Department of Social Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
¹⁵ Department of Anesthesiology and Intensive Care Medicine, Osaka University Graduate School of Medicine, 2-15 Yamadaoka, Suita, Osaka, 565-0871, Japan.
¹⁶ Department of Respiratory Medicine and Allergy, Tosei General Hospital, 160 Nishioiwake-cho, Seto, Aichi, 489-8642, Japan. Electronic address: yshr.kondoh@gmail.com.

PMID: 40591993
DOI: 10.1016/j.resinv.2025.06.013

Abstract

Background: This study aimed to explore the clinical practice of noninvasive respiratory support (NIRS) in COVID-19 patients, and assess its clinical outcomes, safety, and prognostic factors.

Methods: A multicenter, retrospective observational study was conducted with consecutive adult COVID-19 patients who underwent NIRS at nine Japanese hospitals between January 1 and September 30, 2021. NIRS modalities included high-flow nasal cannula oxygen therapy (HFNC), noninvasive ventilation (NIV), and continuous positive airway pressure (CPAP). NIRS failure, defined as intubation or in-hospital death, intubation rate, in-hospital mortality, and the incidence of SARS-CoV-2 infection in health care workers (HCWs) were evaluated. The respiratory rate-oxygenation (ROX) index was examined as a predictor of NIRS failure.

Results: We included 694 patients with a median age of 61 years, of whom 516 (74.4 %) were men. HFNC was the first-line respiratory support for 622 (89.6 %) patients, followed by CPAP in 54 (7.8 %) and NIV in 18 (2.6 %). The NIRS failure rate was 41.5 %, with an intubation rate of 32.0 % and in-hospital mortality of 18.4 %. The ROX index at baseline and 1 and 24 h after NIRS initiation were independent predictors of NIRS failure (odds ratio [95 % CI] 0.89 [0.85-0.94], p < 0.001; 0.84 [0.78-0.89], p < 0.001; 0.84 [0.78-0.90], p < 0.001, respectively). Nine possible NIRS-related HCW infections were reported.

Conclusion: The majority of COVID-19 patients in this study were treated with HFNC, with a NIRS failure rate of about 40 %. The ROX index within 24 h effectively predicted NIRS failure. HCW infections were infrequent, indicating the relative safety of NIRS.

Keywords: COVID-19; Continuous positive airway pressure; High-flow nasal cannula oxygen therapy; Japan; Noninvasive ventilation.