Risk factors affecting the development of pneumothorax in patients followed up in intensive care with a diagnosis of COVID-19.

Background: Pneumothorax is a little known and reported complication of COVID-19. These patients have poorer general outcomes and greater respiratory support requirements, longer hospitalization times, and higher mortality rates. The purpose of this study was to determine which factors predict mortality in patients with tube thoracostomy diagnosed with COVID-19, admitted to the COVID-19 intensive care unit (ICU), and developing pneumothorax.

Methods: This respective, observational study was conducted in all COVID-19 ICUs at the Marmara University Pendik Training and Research Hospital, Türkiye. Patients admitted to the ICU with diagnoses of COVID-19 pneumonia and with chest tubes inserted due to pneumothorax were investigated retrospectively.

Results: One hundred patients with tube thoracostomy were included in the study. Their median age was 68 (57-78), and 63% were men. The median follow-up time was 20 [10-29] days, and the median time from initial reverse transcriptase polymerase chain reaction (RT-PCR) results to tube thoracostomy was 17 [9-23] days. Initial RT-PCR results were positive in 90% of the patients, while 8% were negative, and 2% were unknown. Half the patients exhibited pulmonary involvement at thoracic computed tomography (CT) (n = 50), while 22 patients had COVID-19 reporting and data system (CO-RADS) scores of 5 (22%). Sixty-two patients underwent right tube thoracostomy, 24 left side placement, and 14 bilateral placement. The patients' mean positive end expiratory pressure (PEEP) level was 10.31 (4.48) cm H₂O, with a mean peak inspiratory pressure (PIP) level of 26.69 (5.95) cm H₂O, a mean fraction of inspired oxygen (FiO2) level of 80.06 (21.11) %, a mean respiratory rate of 23.71 (5.62) breaths/min, and a mean high flow nasal cannula (HFNC) flow rate of 70 (8.17) L/min. Eighty-seven patients were intubated (87%), six used non-rebreathable reservoir masks, four HFNC, two non-invasive mechanical ventilation (NIV), and one a simple face mask. Comorbidity was present in 70 patients, 25 had no comorbidity, and the comorbidity status of five was unknown. Comorbidities included hypertension (38%), diabetes mellitus (23%), cardiovascular disease (12%), chronic obstructive pulmonary disease (5%), malignancy (3%), rheumatological diseases (3%), dementia (2%) and other diseases (9%). Twelve of the 100 patients survived. The median survival time was 20 (17.82-22.18) days, and the median 28-day overall survival rate was 29% (20-38%). The multivariate Cox proportional hazards model indicated that age over 68 (HR = 2.23 [95% CI: 1.39-3.56]; p = 0.001), oxygenation status other than by intubation (HR = 2.24 [95% CI: 1.11-4.52]; p = 0.024), and HCO3- below 22 compared with a normal range of 22 to 26 (HR = 1.95 [95% CI: 1.08-3.50]; p = 0.026) were risk factors associated with mortality in patients in the ICU.

Conclusions: Age over 68, receipt of oxygenation other than by intubation, and HCO3- values lower than 22 in patients with COVID-19 pneumonia emerged as prognostic factors associated with mortality in terms of pneumothorax.