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Optimum support by high-flow nasal cannula in acute hypoxemic respiratory failure: effects of increasing flow rates.
Intensive Care Med. 2017 Oct; 43(10):1453-1463.IC

Abstract

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 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.

RESULTS

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.

CONCLUSIONS

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.

Authors+Show Affiliations

Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy. Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via F. Sforza 35, 20122, Milan, Italy.Department of Morphology, Surgery and Experimental Medicine, Section of Anesthesia and Intensive Care, University of Ferrara, Ferrara, Italy.Department of Morphology, Surgery and Experimental Medicine, Section of Anesthesia and Intensive Care, University of Ferrara, Ferrara, Italy.Department of Medicine and Surgery, University of Milan-Bicocca, Monza, Italy.Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy.Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via F. Sforza 35, 20122, Milan, Italy.Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via F. Sforza 35, 20122, Milan, Italy.Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via F. Sforza 35, 20122, Milan, Italy.Department of Morphology, Surgery and Experimental Medicine, Section of Anesthesia and Intensive Care, University of Ferrara, Ferrara, Italy.Department of Morphology, Surgery and Experimental Medicine, Section of Anesthesia and Intensive Care, University of Ferrara, Ferrara, Italy.Department of Anesthesiology, Emergency and Intensive Care Medicine, University of Göttingen, Göttingen, Germany.Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy. antonio.pesenti@unimi.it. Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via F. Sforza 35, 20122, Milan, Italy. antonio.pesenti@unimi.it.Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via F. Sforza 35, 20122, Milan, Italy.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

28762180

Citation

Mauri, Tommaso, et al. "Optimum Support By High-flow Nasal Cannula in Acute Hypoxemic Respiratory Failure: Effects of Increasing Flow Rates." Intensive Care Medicine, vol. 43, no. 10, 2017, pp. 1453-1463.
Mauri T, Alban L, Turrini C, et al. Optimum support by high-flow nasal cannula in acute hypoxemic respiratory failure: effects of increasing flow rates. Intensive Care Med. 2017;43(10):1453-1463.
Mauri, T., Alban, L., Turrini, C., Cambiaghi, B., Carlesso, E., Taccone, P., Bottino, N., Lissoni, A., Spadaro, S., Volta, C. A., Gattinoni, L., Pesenti, A., & Grasselli, G. (2017). Optimum support by high-flow nasal cannula in acute hypoxemic respiratory failure: effects of increasing flow rates. Intensive Care Medicine, 43(10), 1453-1463. https://doi.org/10.1007/s00134-017-4890-1
Mauri T, et al. Optimum Support By High-flow Nasal Cannula in Acute Hypoxemic Respiratory Failure: Effects of Increasing Flow Rates. Intensive Care Med. 2017;43(10):1453-1463. PubMed PMID: 28762180.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Optimum support by high-flow nasal cannula in acute hypoxemic respiratory failure: effects of increasing flow rates. AU - Mauri,Tommaso, AU - Alban,Laura, AU - Turrini,Cecilia, AU - Cambiaghi,Barbara, AU - Carlesso,Eleonora, AU - Taccone,Paolo, AU - Bottino,Nicola, AU - Lissoni,Alfredo, AU - Spadaro,Savino, AU - Volta,Carlo Alberto, AU - Gattinoni,Luciano, AU - Pesenti,Antonio, AU - Grasselli,Giacomo, Y1 - 2017/07/31/ PY - 2017/04/27/received PY - 2017/07/14/accepted PY - 2017/8/2/pubmed PY - 2018/6/26/medline PY - 2017/8/2/entrez KW - Acute lung injury KW - Acute respiratory failure KW - Electrical impedance tomography KW - Esophageal pressure KW - High-flow nasal oxygen KW - Spontaneous breathing SP - 1453 EP - 1463 JF - Intensive care medicine JO - Intensive Care Med VL - 43 IS - 10 N2 - 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 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. RESULTS: 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. CONCLUSIONS: 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. SN - 1432-1238 UR - https://www.unboundmedicine.com/medline/citation/28762180/Optimum_support_by_high_flow_nasal_cannula_in_acute_hypoxemic_respiratory_failure:_effects_of_increasing_flow_rates_ L2 - https://dx.doi.org/10.1007/s00134-017-4890-1 DB - PRIME DP - Unbound Medicine ER -