SGEM#505: Close Enough for (ARF) Acute Respiratory Failure (HFNO vs NIV)

Date: March 11, 2026 Reference: RENOVATE Investigators and the BRICNet Authors; High-Flow Nasal Oxygen vs Noninvasive Ventilation in Patients With Acute Respiratory Failure: The RENOVATE Randomized Clinical Trial. JAMA March 2025 Guest Skeptic: Dr. Rory Spiegel is an emergency medicine and critical care physician known for his work in evidence-based medicine and critical care. He is widely recognized for translating emerging research into practical bedside insights through lectures, writing, and digital medical education. His work focuses on resuscitation science, airway management, and the critical appraisal of medical literature. I’m in Maui at the Centre for Continuing Medical Education Year in Review Course. CCME has been doing courses for almost 40 years. The courses take place at amazing locations in the US, including Maui, Hilton Head, Key West, and NYC. CCME recruits four outstanding educators to review ~260 articles from the past year. It’s a unique course because there are no PowerPoint slides to get in the way of the attendees and the speakers. Two faculty members summarize a few articles on a topic in ½ hour with direct interaction with the speakers. You come to this course…you are up to date on the latest EM literature.   Case: A 64-year-old woman with a history of COPD (GOLD stage III) and hypertension presents to the emergency department (ED) with worsening shortness of breath over the past 24 hours. She reports increased sputum production and wheezing. On arrival, she is tachypneic and speaking in short phrases. Her vital signs are heart rate 104 beats per minute, blood pressure 148/86 mm Hg, respiratory rate 30 breaths per minute, and SpO₂ 88% on 4 L nasal cannula. She is using accessory muscles and has diffuse expiratory wheezes on auscultation. An arterial blood gas reveals pH 7.29, PaCO₂ 58 mm Hg, and PaO₂ 62 mm Hg. Chest X-ray shows hyperinflation without focal consolidation. Background: Acute respiratory failure (ARF) is one of the most common serious respiratory problems managed in emergency medicine and critical care. For decades, noninvasive ventilation (NIV) has been a central part of therapy for selected patients. This is particularly true for those with COPD exacerbations and acute cardiogenic pulmonary edema. By delivering positive pressure, NIV reduces the work of breathing, improves oxygenation and ventilation. This intervention has been shown to reduce intubation rates and mortality in specific populations. However, NIV can be poorly tolerated, requires a tight mask seal and monitoring, and is resource-intensive [1-3]. These downsides can become more problematic in disease states that are not readily reversible over the first few hours. High-flow nasal oxygen (HFNO) has emerged over the past decade as an attractive potential alternative. By delivering heated, humidified oxygen at high flow rates, HFNO improves oxygenation, improves ventilator efficiency by reducing dead space, and is often better tolerated than mask-based ventilation. Its physiologic appeal and ease of use have led to widespread adoption, particularly during the COVID-19 pandemic. Yet enthusiasm has at times outpaced evidence, and important clinical questions remain:  Is HFNO equivalent/non-inferior to NIV in preventing intubation or death? How does it perform across different types of respiratory failure? And when should clinicians choose one over the other? Clinical Question: Is HFNO noninferior to NIV regarding the rates of endotracheal intubation or death at 7 days across five distinct patient groups with ARF? Reference: RENOVATE Investigators and the BRICNet Authors; High-Flow Nasal Oxygen vs Noninvasive Ventilation in Patients With Acute Respiratory Failure: The RENOVATE Randomized Clinical Trial. JAMA March 2025 Population: Hospitalized adults with ARF (hypoxemia plus respiratory effort or tachypnea) classified into 5 groups: Nonimmunocompromised with hypoxemia Immunocompromised with hypoxemia COPD exacerbation with respiratory acidosis Acute cardiogenic pulmonary edema (ACPE) Hypoxemic COVID-19 Exclusions: The main exclusion criteria were if there was an urgent need for endotracheal intubation, hemodynamic instability or contraindications to NIV. Intervention: High-flow nasal oxygen (HFNO) delivered continuously, titrated toward 60 L/min. Comparison: Noninvasive ventilation (NIV) delivered through a face mask. Outcome: Primary Outcome: Endotracheal intubation or death within 7 days. Secondary Outcomes: 28-day and 90-day mortality, mechanical ventilation-free days, and ICU-free days. Type of Study: Multicenter, adaptive, noninferiority randomized clinical trial using a Bayesian hierarchical model with dynamic borrowing across patient groups. Authors’ Conclusions: “Compared with NIV, HFNO met prespecified criteria for noninferiority for the primary outcome of endotracheal intubation or death within 7 day