Regarding: Time to initiation of extracorporeal membrane oxygenation in conventional cardiopulmonary resuscitation affects the patient survival prognosis

Dear Editor,

We read with great interest the article by Sim et al. [1] published in the Journal of Internal Medicine. The authors conducted a retrospective study involving 198 patients to examine the impact of extracorporeal membrane oxygenation (ECMO) initiation timing during routine cardiopulmonary resuscitation (CPR) on patient survival prognosis. The study's findings underscore the crucial role of ECMO in routine CPR, particularly highlighting that an early initiation of ECMO significantly enhances patient survival outcomes. We commend the authors for optimizing the timing of ECMO initiation in clinical practice. However, several aspects warrant further discussion.

First, the article selectively analysed patients who received ECMO but did not provide detailed information regarding the exclusion and selection criteria. For instance, there is no clear explanation of how patients with severe comorbidities or a higher risk of death were managed. This omission could result in a non-representative sample, potentially affecting the generalizability of the study's conclusions.

Second, the article inadequately addresses the neurological prognosis of the patients, as it fails to include data on their long-term neurological outcomes post-discharge (after 3 or 6 months). Given that neurological recovery following cardiac arrest may take an extended period [2], this limitation hinders a comprehensive understanding of the patient's long-term prognosis.

Third, although the article focuses on the timing of ECMO initiation, it does not analyse other concurrent treatments (e.g., high-quality CPR, medications, and temperature management) compared to ECMO. This omission prevents a clear delineation of ECMO's unique contribution relative to other interventions throughout the treatment process [3].

In conclusion, we appreciate the authors for highlighting the significance of timely ECMO initiation during CPR to improve patient survival. This work will raise healthcare professionals’ awareness of the critical importance of early ECMO initiation and contribute to the rapid advancement of this field.

Zegang Ruan: Methodology; writing—original draft; investigation. Yuhao Gan: Methodology; writing—original draft; investigation. Chenyang Xu: Writing—review and editing; supervision.

The authors declare no conflicts of interest.