Original article
Effects of non-invasive respiratory supports on inspiratory effort in moderate-severe COVID-19 patients. A randomized physiological study

https://doi.org/10.1016/j.ejim.2022.04.012Get rights and content

Highlights

  • The recording of esophageal pressure, when starting Non invasive Respiratory Support (NRS), may explain the potential risk in terms of Patient Self Induced Lung Injury and ventilator induced lung injury.

  • Non-invasive ventilation improved the inspiratory effort versus all the other devices, keeping transpulmonary pressure constant in patients in the early phase of acute respiratory failure due to COVID-19 infection

  • This short-term physiological study is the first comparison of respiratory mechanics between all the 3 major forms of NRS applied in spontaneously breathing patients with COVID-19 developing Hypoxemic Acute Respiratory Failure, without chronic respiratory disease.

Abstract

Rationale and objective

Various forms of Non-invasive respiratory support (NRS) have been used during COVID-19, to treat Hypoxemic Acute Respiratory Failure (HARF), but it has been suggested that the occurrence of strenuous inspiratory efforts may cause Self Induced Lung Injury(P-SILI). The aim of this investigation was to record esophageal pressure, when starting NRS application, so as to better understand the potential risk of the patients in terms of P-SILI and ventilator induced lung injury (VILI).

Methods and measurements

21 patients with early de-novo respiratory failure due to COVID-19, underwent three 30 min trials applied in random order: high-flow nasal cannula (HFNC), continuous positive airway pressure (CPAP), and non-invasive ventilation (NIV). After each trial, standard oxygen therapy was reinstituted using a Venturi mask (VM). 15 patients accepted a nasogastric tube placement. Esophageal Pressure (ΔPes) and dynamic transpulmonary driving pressure (ΔPLDyn), together with the breathing pattern using a bioelectrical impedance monitor were recorded. Arterial blood gases were collected in all patients.

Main results

No statistically significant differences in breathing pattern and PaCO2 were found. PaO2/FiO2 ratio improved significantly during NIV and CPAP vs VM. NIV was the only NRS to reduce significantly ΔPes vs. VM (-10,2 ±5 cmH20 vs -3,9 ±3,4). No differences were found in ΔPLDyn between NRS (10,2±5; 9,9±3,8; 7,6±4,3; 8,8±3,6 during VM, HFNC, CPAP and NIV respectively). Minute ventilation (Ve) was directly dependent on the patient's inspiratory effort, irrespective of the NRS applied. 14% of patients were intubated, none of them showing a reduction in ΔPes during NRS.

Conclusions

In the early phase of HARF due to COVID-19, the inspiratory effort may not be markedly elevated and the application of NIV and CPAP ameliorates oxygenation vs VM. NIV was superior in reducing ΔPes, maintaining ΔPLDyn within a range of potential safety.

Keywords

Hypoxemic acute respiratory failure
COVID 19
Non invasive respiratory supports

Cited by (0)

1

Consider both (Schifino and Vega) as primary authors.

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