Correlation between continuous Positive end-expiratory pressure (PEEP) values and occurrence of Pneumothorax and Pneumomediastinum in SARS-CoV2 patients during non-invasive ventilation with Helmet Pneumothorax and Pneumomediastinum in NIV with Helmet CPAP

Abstract

Background: Acute Hypoxemic Respiratory Failure (AHRF) is a common complication of Covid-19 related pneumonia, for which non-invasive ventilation (NIV) with Helmet Continuous Positive Airway Pressure (CPAP) is widely used. The frequency of pneumothorax in COVID-19 was reported in 0.95% of hospitalized patients in 6% of mechanically ventilated patients, and in 1% of a post-mortem case series. Objectives: Aim of our retrospective study was to investigate the incidence of pneumothorax and pneumomediastinum (PNX/PNM) in COVID-19 pneumonia patients treated with Helmet CPAP. Moreover, we examined the correlation between PNX/PNM and Positive end-expiratory pressure (PEEP) values. Methods: We collected data from patients admitted to “Luigi Sacco” University Hospital of Milan from 2 February to 5 May 2020 with COVID-19 pneumonia requiring CPAP. Patients, who need endotracheal intubation (ETI) for any reason except those who needed ETI after PNX/PNM, were excluded.  Population was divided in two groups according to PEEP level used under CPAP (≤10 cmH2O and >10 cmH20). Results: One hundred fifty-four patients were enrolled. In the overall population, 42 patients (27%) were treated with High-PEEP (>10 cmH2O), and 112 with Low-PEEP (≤10 cmH2O). During hospitalization 3 PNX and 2 PNM occurred (3.2%). Out of these five patients, 2 needed invasive ventilation after PNX and died. All the PNX/PNM occurred in the High-PEEP group (5/37 vs 0/112, p<0,001). Conclusion: The incidence of PNX appears to be lower in COVID-19 than SARS and MERS. Considering the association of PNX/PNM with high PEEP we suggest using the lower PEEP as possible to prevent these complications.