Physiopathological rationale of using high-flow nasal therapy in the acute and chronic setting: A narrative review

Abstract

Chronic lung disease and admissions due to acute respiratory failure (ARF) are becoming increasingly common. Consequently, there is a growing focus on optimizing respiratory support, particularly non-invasive respiratory support, to manage these conditions. High flow nasal therapy (HFNT) is a noninvasive technique where humidified and heated gas is delivered through the nose to the airways via small dedicated nasal prongs at flows that are higher than the rates usually applied during conventional oxygen therapy. HFNT enables to deliver different inspired oxygen fractions ranging from 0.21 to 1. Despite having only recently become available, the use of HFNT in the adult population is quite widespread in several clinical settings. The respiratory effects of HNFT in patients with respiratory failure may be particularly relevant for clinicians. In this narrative review, we discuss the main pathophysiological mechanism and rationale for using HFNT in the acute and chronic setting.

High-Flow Nasal Cannula: A Promising Oxygen Therapy for Patients with Severe Bronchial Asthma Complicated with Respiratory Failure

“…Exclusion criteria were as follows: (1) immediate requirement of tracheal intubation; (2) myocardial infarction (cardiothoracic pain with electrocardiogram changes or increased levels of myocardial enzymes); (3) altered consciousness; (4) hemodynamic involvement (noninvasive blood pressure < 90/60 mmHg); (5) pregnancy in women; (6) respiratory rate (RR) > 45 breaths/min; (7) blood pH < 7.30; (8) untreated pneumothorax; (9) end-stage renal disease [estimated glomerular filtration rate (eGFR) < 15 mL/min per 1.73 m 2 or current dialysis]; (10) contraindications for positive-airway pressure devices; (11) pneumonia.…”

“…HFNC is a novel oxygen therapy developed in recent years, in which oxygen at a certain concentration mixed with highflow gas is directly delivered to patients through a nonsealed nasal cannula [6,7]. is oxygen therapy has been assessed by many studies and can be applied to patients with acute hypoxemic respiratory failure, status-post surgery, and respiratory failure without tracheal intubation, immunosuppression, and cardiac insufficiency, thus effectively improving oxygenation [8][9][10][11][12][13][14][15].…”

Effect of High-Flow Nasal Cannula Oxygen Therapy in Immunocompromised Subjects With Acute Respiratory Failure

“…We hypothesized that both HFNC and NIV have similar physiological characteristics, such as generating PEEP, preventing alveolar collapse, reducing dead space, and improving gas exchange. 37,43,44 However, we found that HFNC did not reduce mortality rates compared with conventional oxygen therapy or NIV, possibly because many factors relate to mortality, including underlying immune status, which can affect patient outcomes. For one thing, the underlying immune status can affect patient outcomes.…”

High Flow Nasal Therapy Use in Patients with Acute Exacerbation of COPD and Bronchiectasis: A Feasibility Study

“…High-flow nasal therapy (HFNT) has become an increasingly used modality for the management of patients with type 1 and type 2 acute respiratory failure in different clinical settings [10,11,12]. HFNT delivers high flow gas (up to 60 L/min), warmed to body temperature, saturated for reaching optimal humidification (37 degrees, 44 mg H20/L) and eventually oxygen-enriched to achieve an inspiratory oxygen fraction up to 100% [13,14]. From a physiological point of view, the delivery of warmed humidified gas by HFNT preserves mucociliary transport and promotes mobilization of secretions [15], preventing mucus plugging that may obstruct the airway and decrease ventilation.…”