{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,1]],"date-time":"2026-07-01T05:17:22Z","timestamp":1782883042493,"version":"3.54.5"},"reference-count":23,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2025,12,23]],"date-time":"2025-12-23T00:00:00Z","timestamp":1766448000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Background: Use of high-flow nasal cannula (HFNC) expanded from ICUs to internal medicine\/respiratory wards during and after the COVID-19 pandemic, but safety and effectiveness in non-ICU settings remain uncertain. Methods: We performed a systematic review and meta-analysis of adults (\u226518 years) initiated on HFNC in non-ICU wards. Primary outcomes were in-hospital (or 28-day) mortality and ICU transfer; where available, we compared mortality for HFNC vs. conventional oxygen therapy (COT) in do-not-intubate (DNI) cohorts. Observational studies and trials were eligible. Random-effects models synthesized proportions and risk ratios; risk of bias (ROBINS-I\/RoB 2) and certainty (GRADE) were assessed. Results: Ten studies met the inclusion criteria for any-ward HFNC; subsets contributed data to pooled analyses. Across all non-ICU wards (general wards plus step-up IMCU\/HDU), pooled mortality was 14.0% (95% CI 4.6\u201335.5; I2 \u2248 92%). Pooled ICU transfer after ward\/step-up HFNC start was 20.0% (95% CI 6.3\u201348.1; I2 \u2248 97%). Restricted to internal medicine\/respiratory wards, pooled mortality was 19.8% (95% CI 7.1\u201344.2; I2 \u2248 95%) and ICU transfer 31.2% (95% CI 9.9\u201365.0; I2 \u2248 97%). In step-up units (IMCU\/HDU), ICU transfer appeared lower and less variable (22.0% [95% CI 16.5\u201328.8]; I2 \u2248 10%), suggesting environment-dependent outcomes. In a multicenter DNI COVID-19 cohort, HFNC vs. COT showed no clear mortality difference (RR \u2248 0.90, 95% CI 0.75\u20131.08; adjusted OR \u2248 0.72, 95% CI 0.34\u20131.54). Certainty of evidence for all critical outcomes was very low due to observational design, high inconsistency, and imprecision. Conclusions: HFNC outside the ICU is feasible, but it is related to nontrivial mortality and frequent escalation\u2014particularly on general wards\u2014while step-up units demonstrate more reproducible trajectories. Outcomes appear strongly conditioned by care environment, staffing, monitoring, and escalation pathways. Given very low certainty and substantial heterogeneity, institutions should pair ward HFNC with protocolized reassessment and rapid response\/ICU outreach, and future research should prospectively compare ward HFNC pathways against optimized COT\/NIV using standardized outcomes.<\/jats:p>","DOI":"10.3390\/jcm15010097","type":"journal-article","created":{"date-parts":[[2025,12,26]],"date-time":"2025-12-26T03:06:02Z","timestamp":1766718362000},"page":"97","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["High-Flow Nasal Cannula Outside the ICU: A Systematic Review and Meta-Analysis"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9303-7790","authenticated-orcid":false,"given":"Andrea","family":"Boccatonda","sequence":"first","affiliation":[{"name":"Diagnostic and Therapeutic Interventional Ultrasound Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Policlinico Sant\u2019Orsola-Malpighi, via Massarenti n 9, 40138 Bologna, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0005-2809-1658","authenticated-orcid":false,"given":"Alice","family":"Brighenti","sequence":"additional","affiliation":[{"name":"Diagnostic and Therapeutic Interventional Ultrasound Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Policlinico Sant\u2019Orsola-Malpighi, via Massarenti n 9, 40138 Bologna, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5573-4536","authenticated-orcid":false,"given":"Damiano","family":"D\u2019Ardes","sequence":"additional","affiliation":[{"name":"Institute of \u201cClinica Medica\u201d, Department of Medicine and Aging Science, \u201cG. D\u2019Annunzio\u201d University of Chieti-Pescara, 66100 Chieti, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3745-8368","authenticated-orcid":false,"given":"Luigi","family":"Vetrugno","sequence":"additional","affiliation":[{"name":"Emergency Department, Anesthesia and Intensive Care, Health Integrated Agency of Friuli Centrale, 33028 Tolmezzo, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,12,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"735","DOI":"10.4187\/respcare.06718","article-title":"High-Flow Nasal Cannula Oxygen Therapy Devices","volume":"64","author":"Nishimura","year":"2019","journal-title":"Respir. 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