Macklin effect in critically COVID-19 patients: Observational single-center analysis.

Objective: To analyze the incidence and impact of the Macklin effect (ME) in critically ill COVID-19 patients and its correlation with pneumothorax (PNX), spontaneous pneumomediastinum (SP), and barotraumatic complications (BC).

Design: Observational single-center study.

Setting: Intensive Care Unit (ICU) of a single Italian hospital.

Patients or participants: Critically ill COVID-19 patients aged ≥18 years, with at least one chest computed tomography (Ch-CT) scan and undergoing mechanical ventilation. Patients with pre-existing PNX, SP, or tracheal lesions at ICU admission were excluded.

Interventions: Retrospective analysis of Ch-CT scans to detect ME.

Main variables of interest: ME incidence, its correlation with barotrauma development and mortality.

Results: Among 138 patients, ME was detected in 5.80% (8 cases) on the first Ch-CT scan and in 10.87% (15 cases) at any time during ICU stay. PNX occurred in 17.39% (24 cases) and subcutaneous emphysema in 14.49% (20 cases), with a total BC incidence of 23.91% (33 cases). ME presence on the first Ch-CT scan was significantly associated with PNX (OR 5.5, p = 0.012), SP (OR 12.77, p < 0.001), and BC (OR 11.44, p = 0.004). ME detection on the first Ch-CT scan showed a hazard ratio (HR) of 5.91 (CI 2.41-14.50, p < 0.001) for BC development.

Conclusions: Early ME detection in critically ill COVID-19 patients is crucial, as it is significantly associated with PNX, SP, and BC. Recognizing ME could play a role in improving clinical management and outcomes.