Non-invasive ventilatory support and high-flow nasal oxygen as first-line treatment of acute hypoxemic respiratory failure and ARDS

Abstract

The role of non-invasive respiratory support (high-flow nasal oxygen and noninvasive ventilation) in the management of acute hypoxemic respiratory failure and acute respiratory distress syndrome is debated. The oxygenation improvement coupled with lung and diaphragm protection produced by non-invasive support may help to avoid endotracheal intubation, which prevents the complications of sedation and invasive mechanical ventilation. However, spontaneous breathing in patients with lung injury carries the risk that vigorous inspiratory effort, combined or not with mechanical increases in inspiratory airway pressure, produces high transpulmonary pressure swings and local lung overstretch. This ultimately results in additional lung damage (patient self-inflicted lung injury), so that patients intubated after a trial of noninvasive support are burdened by increased mortality. Reducing inspiratory effort by high-flow nasal oxygen or delivery of sustained positive end-expiratory pressure through the helmet interface may reduce these risks. In this physiology-to-bedside review, we provide an updated overview about the role of noninvasive respiratory support strategies as early treatment of hypoxemic respiratory failure in the intensive care unit. Noninvasive strategies appear safe and effective in mild-to-moderate hypoxemia (PaO 2 /FiO 2 > 150 mmHg), while they can yield delayed intubation with increased mortality in a significant proportion of moderate-to-severe (PaO 2 /FiO 2 ≤ 150 mmHg) cases. High-flow nasal oxygen and helmet noninvasive ventilation represent the most promising techniques for first-line treatment of severe patients. However, no conclusive evidence allows to recommend a single approach over the others in case of moderate-to-severe hypoxemia. During any treatment, strict physiological monitoring remains of paramount importance to promptly detect the need for endotracheal intubation and not delay protective ventilation.

Noninvasive respiratory support for acute respiratory failure due to COVID-19

“…Available data indicate that, in patients with PaO 2 /FiO 2 > 200mmHg, noninvasive respiratory support is safe and effective. Differently, in patients with PaO 2 /FiO 2 ≤ 200 mmHg, the best balance between the benefits and harms of maintaining spontaneous breathing with noninvasive respiratory support has yet to be identified [ 8 , 24 ]. When considering a noninvasive respiratory support trial, the optimal strategy should aim to limit the risk of endotracheal intubation, without increasing the risk of P-SILI: [ 25 ] this is of particular importance given the high failure rate of noninvasive respiratory support in COVID-19 hypoxemic respiratory failure when compared to non-COVID-19 patients [ 26 ▪ ].…”

The Aftermath of the COVID-19 Crisis in Saudi Arabia: Respiratory Rehabilitation Recommendations by Physical Therapists

“…Despite the accumulated data in favor of the use of different non-invasive respiratory therapies for acute respiratory failure in COVID-19, it is not fully understood when to start, escalate, and de-escalate the best respiratory supportive option for the different timing of the disease. For many countries, non-invasive mechanical ventilation (NIMV) is not advised for routine use due to the significant hypoxic respiratory failure rate associated with COVID-19-related hypoxia [37,40,41]. However, evidence has gradually been consolidating in favor of non-invasive ventilatory strategies in the management of hypoxemic respiratory failure caused by COVID-19 [37].…”

Phenotypes of Patients with COVID-19 Who Have a Positive Clinical Response to Helmet Noninvasive Ventilation

“…High-flow nasal oxygen is a simple, easy-to-use tool applied worldwide ( 8 ). Conversely, helmet noninvasive ventilation is a less diffuse technique ( 9 ) and requires a mechanical ventilator and personnel expertise, whose shortage in the context of the COVID-19 pandemic may limit the number of patients who may have access to this kind of support. Pa O 2 /(F i O 2 × VAS dyspnea) and Pa CO 2 are bedside-available parameters that may help identify patients in whom helmet noninvasive ventilation as applied in the HENIVOT trial may improve clinical outcome ( 7 , 10 ).…”