To the Editor As Kobe et al. reported (1), treatment strategies for acute coronavirus disease 2019 (COVID-19) are rapidly evolving. However, the long-term consequences of COVID-19 remain largely unknown, although the development of pulmonary fibrosis secondary to acute respiratory distress syndrome (ARDS) is inevitable in many severe cases of COVID-19 (2). We herein report the associations observed between the duration of intensive respiratory support and the risk of long-lasting respiratory failure in patients with COVID-19.
At National Hospital Organization Fukuoka National Hospital, from January 2020 to December 2021, 18 patients with diagnoses of COVID-19 required high-flow nasal cannula (HFNC) and/or mechanical ventilation. All subjects were naïve to vaccination against severe acute respiratory syndrome coronavirus 2 and survived by virtue of standard medications, including high-dose systemic steroids. The durations of the above-mentioned respiratory management were within 28 days in 13 cases (early recovered group) and more than 28 days in 5 cases (refractory group). Within 6 months after the onset of COVID-19, oxygen therapy was withdrawn in 12 cases (92.3%) among the early recovery group and in none (0%) among the refractory group. Among the subjects who discontinued oxygen supply successfully, a strong correlation (coefficient of determination of 0.97) was observed between the durations of intensive respiratory support and supplemental oxygen therapy (Figure).
Figure.
Correlations between the duration of intensive respiratory support and the period of oxygen supply. R2: coefficient of determination
Besides those with COVID-19, only a few survivors of ARDS received supplemental oxygen for more than six months (3). With regard to COVID-19, however, more than half of severe cases developed diffuse fibrotic changes in the lungs as a serious sequela (4), leading to an increase in the prescription of long-term oxygen therapy (5). Although this survey was a single-center analysis with a small sample size, cases of COVID-19 with the use of HFNC and/or mechanical ventilation for more than four weeks were determined to be at high risk for developing long-term respiratory failure. Since chronic respiratory failure after COVID-19 recovery is an emerging threat to global health, advances in post-COVID-19 management as well as preventive measures and initial treatment against COVID-19 are highly warranted.
The study was approved by the National Hospital Organization Fukuoka National Hospital Institutional Review Board for Clinical Research on May 10, 2022 (#F4-5). Informed consent was waived due to the retrospective nature of the study.
The authors state that they have no Conflict of Interest (COI).
References
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