Noninvasive respiratory support and patient self-inflicted lung injury in COVID-19: a narrative review

Abstract

Coronavirus disease 2019 (COVID-19) pneumonia is associated with hypoxemic respiratory failure, ranging from mild to severe. Due to the worldwide shortage of intensive care unit beds, a relatively high number of patients with respiratory failure are receiving prolonged non-invasive respiratory support, even when their clinical status would have required invasive mechanical ventilation. There are few experimental and clinical data reporting that vigorous breathing effort during spontaneous ventilation can worsen lung injury and cause a phenomenon that has been termed patient self-inflicted lung injury (P-SILI). The aim of this narrative review is to provide an overview of P-SILI pathophysiology and the role of non-invasive respiratory support in COVID-19 pneumonia. Respiratory mechanics, vascular compromise, viscoelastic properties, lung inhomogeneity, work of breathing, and oesophageal pressure swings are discussed. The concept of P-SILI has been widely investigated in recent years, but controversies persist regarding its mechanisms. To minimize the risk of P-SILI, intensivists should better understand its underlying pathophysiology to optimize the type of non-invasive respiratory support provided to patients with COVID-19 pneumonia, as well as decide on the optimal timing of intubation for these patients.

Extracorporeal Membrane Oxygenation for COVID 2019-Acute Respiratory Distress Syndrome: Comparison between First and Second Waves (Stage 2)

“…To note, no significant difference in adjuvant treatment (prone positioning, neuromuscular blockade, inhaled nitric oxide) before ECMO implantation was noticed between the two groups. Thus, the more severe respiratory phenotype during the second wave may be due to (1) an ECMO initiation at a more advanced stage of the disease, and (2) patient self-inflicted lung injury secondary to vigorous respiratory drive during non-invasive support as already described in other reports [3,13]. As such, we observe much more pneumothorax before ECMO canulation in the second wave group.…”

“…ECMO, ventilation, biological parameters, and SOFA score at day one, three, and seven under V-V ECMO between first wave and second wave groups are reported in Tables 3, S2 and S3. The SOFA score was not statistically different between the first (12 (10)(11)(12)(13)(14)) and the second wave groups (11 (9.5-13); p = 0.07) at day one under V-V ECMO. During the ECMO course, 44/50 (88%) patients received glucocorticoids, respectively, 22/24 (91.7%) in the first wave group and 22/26 (84.6%) in second wave group, p = 0.669.…”

“…No difference was observed regarding adjuvant treatment for ARDS pre-ECMO between the two groups. In the second wave group, all patients received glucocorticoids with a median time to ECMO of 13 (11)(12)(13)(14)(15)(16)(17)(18)(19) days while only 16.7% patients of the first wave group with a median time to ECMO of 7.5 (5.3-9) days (p = 0.015). Antiviral treatments were significantly more regularly administered in the first wave group in comparison to the second wave group.…”

“…No significant difference between groups was noted concerning the use of inhaled nitric oxide and almitrine. Ninety-eight percent patients received red cells transfusion under ECMO with median 8.5 (5)(6)(7)(8)(9)(10)(11)(12)(13)(14) packed red blood cells, 34% received platelets, 28% received fresh frozen plasma, and 14% received fibrinogen concentrate under ECMO with no difference between the two groups. For more details, refer to Table S4.…”

COVID-19-Associated Pneumomediastinum and Pneumothorax: A Case Series

“…Non-intubated spontaneously breathing patients have a predilection for P-SILI owing to various factors -increased stress and strain of the lung, inhomogeneous distribution of ventilation leading to pendelluft creation, changes in lung perfusion leading to ventilation-perfusion mismatch, and patient-ventilator asynchronies during NIV. The P-SILI together with the COVID-19-induced cytokine storm results in a diffuse alveolar injury making the alveoli more prone to rupture [4,7]. Our three patients who were initially managed on oxygen therapy using NRBM and proning, developed acute onset of breathlessness for which NIV was initiated, and an immediate repeat CT thorax revealed PM and bilateral minimal PTX.…”