Future prospective studies should explore the causality between low etCO₂ and severe PPCs.

Potential mechanisms include hyperventilation causing ventilator-induced lung injury, ventilation-perfusion mismatching, or an underlying pulmonary pathology.

Severe PPCs were more common in the ‘low etCO₂’ group (35 % vs. 18 %). Propensity score matching did not alter the results, showing a robust association.