Optimum support by high-flow nasal cannula in acute hypoxemic respiratory failure: effects of increasing flow rates
- 3.3k Downloads
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.
A prospective randomized cross-over study was performed in non-intubated patients with patients AHRF and a PaO2/FiO2 (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 FiO2 (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 (PTPPes), and lung volume, by electrical impedance tomography.
Seventeen patients with AHRF were enrolled in the study. At increasing flow rate, HFNC reduced ΔPes (p < 0.001) and PTPPes (p < 0.001), while end-expiratory lung volume (ΔEELV), tidal volume to ΔPes ratio (V T/ΔPes, which corresponds to dynamic lung compliance) and oxygenation improved (p < 0.01 for all factors). Higher HFNC flow rate also progressively reduced minute ventilation (p < 0.05) without any change in arterial CO2 tension (p = 0.909). The decrease in ΔPes, PTPPes and minute ventilation at increasing flow rates was better described by exponential fitting, while ΔEELV, V T/ΔPes and oxygenation improved linearly.
In this cohort of patients with AHRF, an increasing HFNC flow rate progressively decreased inspiratory effort and improved lung aeration, dynamic compliance and oxygenation. Most of the effect on inspiratory workload and CO2 clearance was already obtained at the lowest flow rate.
KeywordsHigh-flow nasal oxygen Spontaneous breathing Electrical impedance tomography Esophageal pressure Acute lung injury Acute respiratory failure
Compliance with ethical standards
Conflicts of interest
The authors declare that they have no conflict of interest related to the present study.
Ethical approval and consent to participate
The Ethical Committee of the Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy approved the study (reference number: 1628/2015), and informed consent was obtained from each patient according to local regulations.
- 3.Maggiore SM, Idone FA, Vaschetto R, Festa R, Cataldo A, Antonicelli F, Montini L, De Gaetano A, Navalesi P, Antonelli M (2014) Nasal high-flow versus Venturi mask oxygen therapy after extubation. Effects on oxygenation, comfort, and clinical outcome. Am J Respir Crit Care Med 190(3):282–288CrossRefPubMedGoogle Scholar
- 4.Frat JP, Thille AW, Mercat A, Girault C, Ragot S, Perbet S, Prat G, Boulain T, Morawiec E, Cottereau A, Devaquet J, Nseir S, Razazi K, Mira JP, Argaud L, Chakarian JC, Ricard JD, Wittebole X, Chevalier S, Herbland A, Fartoukh M, Constantin JM, Tonnelier JM, Pierrot M, Mathonnet A, Béduneau G, Delétage-Métreau C, Richard JC, Brochard L, Robert R, FLORALI Study Group; REVA Network (2015) High-flow oxygen through nasal cannula in acute hypoxemic respiratory failure. N Engl J Med 372(23):2185–2196CrossRefPubMedGoogle Scholar
- 5.Stéphan F, Barrucand B, Petit P, Rézaiguia-Delclaux S, Médard A, Delannoy B, Cosserant B, Flicoteaux G, Imbert A, Pilorge C, Bérard L, BiPOP Study Group (2015) High-flow nasal oxygen vs noninvasive positive airway pressure in hypoxemic patients after cardiothoracic surgery: a randomized clinical trial. JAMA 313(23):2331–2339CrossRefPubMedGoogle Scholar
- 6.Hernández G, Vaquero C, González P, Subira C, Frutos-Vivar F, Rialp G, Laborda C, Colinas L, Cuena R, Fernández R (2016) Effect of postextubation high-flow nasal cannula vs conventional oxygen therapy on reintubation in low-risk patients: a randomized clinical trial. JAMA 315(13):1354–1361CrossRefPubMedGoogle Scholar
- 7.Hernández G, Vaquero C, Colinas L, Cuena R, González P, Canabal A, Sanchez S, Rodriguez ML, Villasclaras A, Fernández R (2016) Effect of postextubation high-flow nasal cannula vs noninvasive ventilation on reintubation and postextubation respiratory failure in high-risk patients: a randomized clinical trial. JAMA 316(15):1565–1574CrossRefPubMedGoogle Scholar
- 19.Mojoli F, Chiumello D, Pozzi M, Algieri I, Bianzina S, Luoni S, Volta CA, Braschi A, Brochard L (2015) Esophageal pressure measurements under different conditions of intrathoracic pressure. An in vitro study of second generation balloon catheters. Minerva Anestesiol 81(8):855–864PubMedGoogle Scholar
- 21.Mauri T, Yoshida T, Bellani G, Goligher E, Carteaux G, Rittayamai N, Mojoli F, Chiumello D, Piquilloud L, Grasso S, Jubran A, Laghi F, Magder S, Pesenti A, Loring S, Gattinoni L, Talmor D, Blanch L, Amato M, Chen L, Brochard L, Mancebo J, the PLeUral pressure working Group (PLUG—Acute Respiratory Failure section of the European Society of Intensive Care Medicine) (2016) Esophageal and transpulmonary pressure in the clinical setting: meaning, usefulness and perspectives. Intensive Care Med 42:1360–1373CrossRefPubMedGoogle Scholar
- 22.Mauri T, Eronia N, Abbruzzese C, Marcolin R, Coppadoro A, Spadaro S, Patroniti N, Bellani G, Pesenti A (2015) Effects of sigh on regional lung strain and ventilation heterogeneity in acute respiratory failure patients undergoing assisted mechanical ventilation. Crit Care Med 43(9):1823–1831CrossRefPubMedGoogle Scholar
- 31.Mauri T, Eronia N, Turrini C, Battistini M, Grasselli G, Rona R, Volta CA, Bellani G, Pesenti A (2016) Bedside assessment of the effects of positive end-expiratory pressure on lung inflation and recruitment by the helium dilution technique and electrical impedance tomography. Intensive Care Med 42(10):1576–1587CrossRefPubMedGoogle Scholar