Optimum support by high-flow nasal cannula in acute hypoxemic respiratory failure: effects of increasing flow rates

• Published in: Intensive care medicine 2017-10, Vol.43 (10), p.1453-1463
• Main Authors: Mauri, Tommaso, Alban, Laura, Turrini, Cecilia, Cambiaghi, Barbara, Carlesso, Eleonora, Taccone, Paolo, Bottino, Nicola, Lissoni, Alfredo, Spadaro, Savino, Volta, Carlo Alberto, Gattinoni, Luciano, Pesenti, Antonio, Grasselli, Giacomo
• Format: Article
• Language: English
• Subjects: Adult; Aeration; Aged; Analysis; Anesthesiology; Blood Gas Analysis; Blood pressure; Breathing; Cannula; Cannulae; Carbon dioxide; Critical Care - methods; Critical Care Medicine; Cross-Over Studies; Electrical impedance; Emergency Medicine; Esophagus; Female; Flow velocity; Forced Expiratory Flow Rates; Gases; Humans; Hypoxia - physiopathology; Hypoxia - therapy; Intensive; Intensive care; Lungs; Male; Mechanical ventilation; Medical materials; Medicine; Medicine & Public Health; Middle Aged; Noninvasive Ventilation - methods; Organ Dysfunction Scores; Oxygen; Oxygen Inhalation Therapy - methods; Oxygenation; Pain Medicine; Partial pressure; Patients; Pediatrics; Pneumology/Respiratory System; Prospective Studies; Respiration; Respiratory failure; Respiratory insufficiency; Respiratory Insufficiency - physiopathology; Respiratory Insufficiency - therapy; Respiratory therapy; Seven-Day Profile Publication; Skin care products; Tidal energy; Tidal power; Time Factors; Ventilation; Work of Breathing
• ISSN: 0342-4642; 1432-1238
• DOI: 10.1007/s00134-017-4890-1

Purpose Limited data exist on the correlation between higher flow rates of high-flow nasal cannula (HFNC) and its physiologic effects in patients with acute hypoxemic respiratory failure (AHRF). We assessed the effects of HFNC delivered at increasing flow rate on inspiratory effort, work of breathing, minute ventilation, lung volumes, dynamic compliance and oxygenation in AHRF patients. Methods A prospective randomized cross-over study was performed in non-intubated patients with patients AHRF and a PaO 2 /FiO 2 (arterial partial pressure of oxygen/fraction of inspired oxygen) ratio of ≤300 mmHg. A standard non-occlusive facial mask and HFNC at different flow rates (30, 45 and 60 l/min) were randomly applied, while maintaining constant FiO 2 (20 min/step). At the end of each phase, we measured arterial blood gases, inspiratory effort, based on swings in esophageal pressure (ΔPes) and on the esophageal pressure–time product (PTP Pes ), and lung volume, by electrical impedance tomography. Results Seventeen patients with AHRF were enrolled in the study. At increasing flow rate, HFNC reduced ΔPes ( p