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 Table of Contents  
Year : 2017  |  Volume : 1  |  Issue : 1  |  Page : 43-46

High-flow oxygen therapy in hypoxemic respiratory failure: Review

Department of Respiratory Therapy Sciences, Inaya Medical College, Riyadh, Saudi Arabia

Date of Web Publication23-Jun-2017

Correspondence Address:
Saumy Johnson
Department of Respiratory Therapy Sciences, Inaya Medical College, Riyadh
Saudi Arabia
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/sccj.sccj_8_17

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High-flow oxygen therapy is a novel technology in the treatment of hypoxemic respiratory failure (HRF). The effect in neonatal and pediatric population is well known, but its efficiency in the adult patient group is not well proven. This review tried to discuss various aspects of high-flow nasal cannula (HFNC) in terms of its components, effects, and the evidence available. High-flow nasal cannula is being used as the first choice of intervention in patients with acute HRF, especially in patients who does not have critical hypercapnia. Clinicians should be very selective while choosing the adult patients for HFNC.

Keywords: Hypoxemic respiratory failure, nasal oxygen, oxygen therapy

How to cite this article:
Johnson S. High-flow oxygen therapy in hypoxemic respiratory failure: Review. Saudi Crit Care J 2017;1:43-6

How to cite this URL:
Johnson S. High-flow oxygen therapy in hypoxemic respiratory failure: Review. Saudi Crit Care J [serial online] 2017 [cited 2023 Jun 4];1:43-6. Available from: https://www.sccj-sa.org/text.asp?2017/1/1/43/208925

  Introduction Top

Hypoxemic respiratory failure (HRF) is common and frequent in patients admitted to intensive care unit and this may lead to organ dysfunction which can be severe in most cases.[1],[2] HRF can be because of various causes, which should be diagnosed concurrently while treating the patients symptomatically.[3],[4] Conventionally, HRF is treated with noninvasive or invasive mechanical ventilation which improves oxygenation, unloads the work of respiratory muscles, enhances better gas exchange, and provides adequate time to treat the underlying etiology which causes hypoxemia. Conventional strategies to treat hypoxemia has beneficial effects and some adverse effects such as increased incidence of infection, cardiovascular compromise, and increased mortality.[5],[6]

  Method of Delivery Top

High-flow nasal cannula (HFNC) is a method of ventilation wherein the combination of air and oxygen at high flow is delivered through a humidified circuit. This flow usually exceeds the patient's spontaneous breathing demand. Two systems that are currently used for HFNC are the Optiflow Nasal Interfaces (Fisher and Paykel Healthcare, New Zealand) and the Vapotherm system (Vapotherm Inspiration Healthcare, United Kingdom).[7],[8],[9] HFNC provides heated and humidified gases and delivers continuous positive airway pressure; however, the precise level is not known.[10]

[Figure 1]a shows the apparatus for the delivery of HFNC.

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At the time, when supplemental oxygen is necessary, Optiflow can deliver flows up to 60 L/min to meet peak inspiratory demand, thus reducing O2 dilution by room air. As shown in [Figure 1]b the maximum oxygen flow from a face mask is limited to nearly 10 L/min which is not appropriate to meet the patient's peak inspiratory demand. To resolve the variance, room air is entrained and diluting the oxygen that is provided. On the other hand, Optiflow is capable to meet this patient's peak inspiratory demand of 30 L/min confirming a precise provision of inspiratory fraction of oxygen (FiO2) to the patient.[11]

HFNC device consist of an air/oxygen blender, an active heated humidifier, a single heated circuit, and a nasal cannula [Figure 2] and [Figure 3]. At the air/oxygen blender, the FiO2 is set from 0.21 to 1.0 in a flow of up to 60 L/min. In this device, the inspired gas is heated and humidified using active humidifier and is provided through the circuit which is connected to the patient through a nasal cannula [Figure 2].
Figure 2: Circuit of the high-flow nasal cannula system

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Figure 3: Optiflow nasal cannula (a) adult and (b)infant

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HFNC decreases oxygen dilution, decreases respiratory dead space, and creates certain positive airway pressure, due to the expiratory resistance produced by the constant high flow delivered. The heated humidification eases secretion clearance and reduction of the development of bronchial hyperresponse.[12]

A study was done by Möller et al.[13] to test if nasal high flow (NHF) can clear dead space in two different models of the upper nasal airways. The models include (1) simple tube model comprising an outlet to simulate the nasal valve area, joined to a cylindrical tube to simulate the nasal cavity (2) a complex anatomically illustrative upper airway model, made from segmented computed tomography scan images of a healthy volunteer. Once the models were filled with tracer gases, NHF was supplied at different flow rates such as 15, 30, and 45 L/min. The tracer-gas clearance was determined using dynamic infrared CO2 spectroscopy and radioactive gamma camera imaging. The finding was similar for flow-dependent tracer-gas clearance in the models. Anatomically-based model showed complete tracer-gas removal from the nasal cavities within 1.0 s. The level of clearance in the nasal cavities increased by 1.8 mL/s for every 1.0 L/min increase in the rate of NHF. The main finding of this study was the fast-occurring clearance of nasal cavities by NHF therapy, which is capable of decreasing rebreathing from the dead space.

This review summarizes few articles in [Table 1] which are done in the field of HFNC in postextubation, preoxygenation, immunocompromised patients, and hematological malignancies.
Table 1: Original studies on high-flow nasal cannula

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  Discussion Top

HFNC therapy has been shown to decrease ventilatory requirements by flushing out the dead space of the upper airway and enhances oxygenation by achieving patient demand with high oxygen concentrations and generating a low-level end-expiratory pressure. Gas delivered at body temperature and humidity is important for patient comfort and tolerance of therapy. Parke et al. did a study in a group of normal individuals in which they reported high-flow nasal oxygen at 100 L/min resulting in a rise in pharyngeal airway pressure of 1 cm H2O/10 L/min of flow. Respiratory rate decreased as the flow increased and electrical impedance tomography confirmed a small increase in end-expiratory lung volume.[21] As this study was done in healthy individuals, it cannot be extrapolated to patients with lung pathology; however, the development of the device might be useful to replace or to be considered as an alternative to noninvasive ventilation (NIV) with facemask.

  Conclusion Top

High-flow nasal cannula is being used as the first choice of intervention in patients with acute HRF, especially in patients who does not have critical hypercapnia, hemodynamical instability, and other reasons such as decreased level of consciousness which necessitates the use of NIV or invasive mechanical ventilation. Clinicians should be very selective while choosing the adult patients for HFNC. There is a need for large randomized studies comparing NIV and oxygen therapy modalities with HFNC to actually confirm the indications and contraindications of its use.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Estenssoro E. The FINNALI study on acute respiratory failure: Not the final cut. Intensive Care Med 2009;35:1328-30.  Back to cited text no. 1
Azevedo LCP, Caruso P, Silva UVA, Torelly AP, Silva E, Rezende E, et al. Outcomes for patients with cancer admitted to the ICU requiring ventilatory support: Results from a prospective multicenter study. Chest 2014;146:257-66.  Back to cited text no. 2
Azoulay E, Thiéry G, Chevret S, Moreau D, Darmon M, Bergeron A, et al. The prognosis of acute respiratory failure in critically ill cancer patients. Medicine (Baltimore) 2004;83:360-70.  Back to cited text no. 3
Canet E, Osman D, Lambert J, Guitton C, Heng AE, Argaud L, et al. Acute respiratory failure in kidney transplant recipients: A multicenter study. Crit Care 2011;15:R91.  Back to cited text no. 4
Soni N, Williams P. Positive pressure ventilation: What is the real cost? Br J Anaesth 2008;101:446-57.  Back to cited text no. 5
Mitaka C, Nagura T, Sakanishi N, Tsunoda Y, Amaha K. Two-dimensional echocardiographic evaluation of inferior vena cava, right ventricle, and left ventricle during positive-pressure ventilation with varying levels of positive end-expiratory pressure. Crit Care Med 1989;17:205-10.  Back to cited text no. 6
Fisher and Paykel Healthcare Humidification Review, Optiflow; 2006. Available from: http://www.fphcare.com/humidification/humidity/asp.  Back to cited text no. 7
Parke R, McGuiness S, Eccleston M. Delivering Humidified High Flow Therapy at Increasing Gas Flow Rates Generates High Airway Pressure. 21st European Society of Intensive Care Medicine Annual Congress; 2008. p. S401-5.  Back to cited text no. 8
Malinowski T, Lamberti J. Oxygen concentrations via nasal cannula at high flow rates. Respir Care 2002;47:1039.  Back to cited text no. 9
Kubicka ZJ, Limauro J, Darnall RA. Heated, humidified high-flow nasal cannula therapy: Yet another way to deliver continuous positive airway pressure? Pediatrics 2008;121:82-8.  Back to cited text no. 10
Roca O, Riera J, Torres F, Masclans JR. High-flow oxygen therapy in acute respiratory failure. Respir Care 2010;55:408-13.  Back to cited text no. 11
Nishimura M. High-flow nasal cannula oxygen therapy in adults: Physiological benefits, indication, clinical benefits, and adverse effects. Respir Care 2016;61:529-41.  Back to cited text no. 12
Möller W, Celik G, Feng S, Bartenstein P, Meyer G, Oliver E, et al. Nasal high flow clears anatomical dead space in upper airway models. J Appl Physiol 2015;118:1525-32.  Back to cited text no. 13
Simon M, Wachs C, Braune S, de Heer G, Frings D, Kluge S. High-flow nasal cannula versus bag-valve-mask for preoxygenation before intubation in subjects with hypoxemic respiratory failure. Respir Care 2016;61:1160-7.  Back to cited text no. 14
Simon M, Braune S, Frings D, Wiontzek AK, Klose H, Kluge S. High-flow nasal cannula oxygen versus non-invasive ventilation in patients with acute hypoxaemic respiratory failure undergoing flexible bronchoscopy – A prospective randomised trial. Crit Care 2014;18:712.  Back to cited text no. 15
Lemiale V, Mokart D, Mayaux J, Lambert J, Rabbat A, Demoule A, et al. The effects of a 2-h trial of high-flow oxygen by nasal cannula versus Venturi mask in immunocompromised patients with hypoxemic acute respiratory failure: A multicenter randomized trial. Crit Care 2015;19:380.  Back to cited text no. 16
Hernández G, Vaquero C, Colinas L, Cuena R, González P, Canabal A, et al. 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 2016;316:1565-74.  Back to cited text no. 17
Lee HY, Rhee CK, Lee JW. Feasibility of high-flow nasal cannula oxygen therapy for acute respiratory failure in patients with hematologic malignancies: A retrospective single-center study. J Crit Care 2015;30:773-7.  Back to cited text no. 18
Brotfain E, Zlotnik A, Schwartz A, Frenkel A, Koyfman L, Gruenbaum SE, et al. Comparison of the effectiveness of high flow nasal oxygen cannula vs. standard non-rebreather oxygen face mask in post-extubation intensive care unit patients. Isr Med Assoc J 2014;16:718-22.  Back to cited text no. 19
Vourc'h M, Asfar P, Volteau C, Bachoumas K, Clavieras N, Egreteau PY, et al. High-flow nasal cannula oxygen during endotracheal intubation in hypoxemic patients: A randomized controlled clinical trial. Intensive Care Med 2015;41:1538-48.  Back to cited text no. 20
Parke RL, Bloch A, McGuinness SP. Effect of very-high-flow nasal therapy on airway pressure and end-expiratory lung impedance in healthy volunteers. Respir Care 2015;60:1397-403.  Back to cited text no. 21


  [Figure 1], [Figure 2], [Figure 3]

  [Table 1]


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