A 45-year-old man presents to the ED with shortness of breath that began 4 hours ago. He reports 2 days of cough, fever, and pleuritic chest pain. He is speaking in 3–4 word phrases, breathing at 33 breaths/minute, and appears in mild to moderate respiratory distress. He has right middle lobe crackles on auscultation. An arterial blood gas shows a pH of 7.48, a PaO2 of 54 mm Hg, and a PaCO2 of 33 mm Hg. What physiologic benefit does high-flow nasal cannula oxygen provide?
Decreases functional residual capacity
Improves carbon dioxide washout of physiologic dead space
Maximizes the dilution of oxygen
Provides fewer peak inspiratory flows than required
Riera J, Pérez P, Cortés J, Roca O, Masclans JR, Rello J. Effect of high-flow nasal cannula and body position on end-expiratory lung volume: a cohort study using electrical impedance tomography. Respir Care. 2013;58(4):589–596. https://rc.rcjournal.com/content/58/4/589.full
Rittayamai N, Tscheikuna J, Rujiwit P. High-flow nasal cannula versus conventional oxygen therapy after endotracheal extubation: a randomized crossover physiologic study. Respir Care. 2014;59(4):485–490. https://rc.rcjournal.com/content/59/4/485.full
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Post Peer Reviewed By: Salim R. Rezaie, MD (Twitter/X: @srrezaie)