ROX index dynamics according to HFNC success in ICU patients with COVID-19-related acute respiratory failure

Abstract

<b>Introduction:</b> High flow nasal cannula (HFNC) therapy has been shown to be useful in the treatment of patients with acute respiratory failure (ARF) caused by SARS-CoV-2. The ROX index can help predict the success of HFNC in COVID-19 related ARF. However, timing of ROX- index assessment is still unclear to protect the patients from complications due to early or delayed intubation. <b>Methods:</b> A single-center, retrospective and observational study was performed on patients with ARF secondary to COVID-19 treated with HFNC, between April 2020 and January 2022.&nbsp;The primary aim of the study was to evaluate between ROX index changes within first 48 hours of the therapy to predict HFNC success. <b>Results:</b> In the study period, 69 patients managed with HFNC for at least 2 hours. While 24 patients (34.7%) were successfully weaned from HFNC, 45 (65.3%) patients were failed. Overall mortality at day 28 was 44.9%. ROX indices were lower in HFNC failure group through the 12th, 24th, 48th hours of the therapy, no significant change was observed (p=0.33).&nbsp;While an overall increase in ROX index patterns were detected in patients weaned from HFNC (p=0.002). Pairwise analyses revealed that ROX indexes remain stable during the first 8th hours in both groups, then improved to 12th hours of the therapy in successfully HFNC-weaned patients. <b>Conclusion:</b> Dynamic assessments of the ROX indexes could be more suggestive rather than a point assessment to identify patients who would benefit from the HFNC or deteriorate in COVID-19 related ARF.