Risk Factors for Pulmonary Air Leak and Clinical Prognosis in Patients With COVID-19 Related Acute Respiratory Failure: A Retrospective Matched Control Study.

Background: The role of excessive inspiratory effort in promoting alveolar and pleural rupture resulting in air leak (AL) in patients with SARS-CoV-2 induced acute respiratory failure (ARF) while on spontaneous breathing is undetermined.
Methods: Among all patients with COVID-19 related ARF admitted to a respiratory intensive care unit (RICU) and receiving non-invasive respiratory support, those developing an AL were and matched 1:1 [by means of PaO2/FiO2 ratio, age, body mass index-BMI and subsequent organ failure assessment (SOFA)] with a comparable population who did not (NAL group). Esophageal pressure (ΔP _es ) and dynamic transpulmonary pressure (ΔP _L ) swings were compared between groups. Risk factors affecting AL onset were evaluated. The composite outcome of ventilator-free-days (VFD) at day 28 (including ETI, mortality, tracheostomy) was compared between groups.
Results: Air leak and NAL groups ( n = 28) showed similar ΔP _es , whereas AL had higher ΔP _L (20 [16-21] and 17 [11-20], p = 0.01, respectively). Higher ΔP _L (OR = 1.5 95%CI[1-1.8], p = 0.01), positive end-expiratory pressure (OR = 2.4 95%CI[1.2-5.9], p = 0.04) and pressure support (OR = 1.8 95%CI[1.1-3.5], p = 0.03), D-dimer on admission (OR = 2.1 95%CI[1.3-9.8], p = 0.03), and features suggestive of consolidation on computed tomography scan (OR = 3.8 95%CI[1.1-15], p = 0.04) were all significantly associated with AL. A lower VFD score resulted in a higher risk (HR = 3.7 95%CI [1.2-11.3], p = 0.01) in the AL group compared with NAL. RICU stay and 90-day mortality were also higher in the AL group compared with NAL.
Conclusion: In spontaneously breathing patients with COVID-19 related ARF, higher levels of ΔP _L , blood D-dimer, NIV delivery pressures and a consolidative lung pattern were associated with AL onset.
Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
(Copyright © 2022 Tonelli, Bruzzi, Manicardi, Tabbì, Fantini, Castaniere, Andrisani, Gozzi, Pellegrino, Trentacosti, Dall’Ara, Busani, Franceschini, Baroncini, Manco, Meschiari, Mussini, Girardis, Beghè, Marchioni and Clini.)