Response to “Severe Necrotizing Lung Infections: Definitions and Therapeutic Indications”

We greatly appreciate the comments of Rakovich and Kurz regarding our recently published article. In our correspondence, we clarify several issues raised by the authors regarding the definition, pathophysiology and management of necrotizing lung infections (NLI) in patients requiring VV-ECMO support for severe respiratory failure. We emphasize that there is currently no universally accepted radiological definition or volumetric cut-off for necrotizing pneumonia. Our study intentionally used a broader CT-based definition encompassing necrotizing pneumonia, lung abscess and necrotizing cavitation to capture the clinically relevant spectrum of destructive pulmonary complications observed in critically ill ECMO patients. Following the authors' suggestion, we additionally re-analysed our cohort using a proposed threshold of >50% non-enhancing consolidated parenchyma, with 55% of patients still fulfilling these criteria. We further clarify that our cohort consisted primarily of patients with severe ARDS requiring ECMO support in whom NLI developed as a complication of extensive pre-existing lung injury, rather than as the primary cause of refractory hypoxemia. The high proportion of viral pneumonia, particularly COVID-19, concomitant thromboembolic events, corticosteroid exposure and severe ventilation/perfusion abnormalities likely contributed to the high incidence of necrotic complications observed in our cohort. Finally, we agree that surgical intervention should remain a last-resort strategy in these patients and provide additional clinical data regarding surgically treated patients to better illustrate the severity of disease and indications for operative management.