Rox Index Dynamics According to High Flow Nasal Cannula Success in Intensive Care Unit Patients with COVID-19-Related...

High-flow nasal cannula therapy has been shown to be useful in the treatment of patients with acute respiratory failure caused by severe acute respiratory syndrome-coronavirus disease-2. The ROX index can help predict the success of high-flow nasal cannula in coronavirus disease-19-related acute respiratory failure. However, the timing of ROX- index assessment is still unclear to protect the patients from complications due to early or delayed intubation.

To evaluate the relation between ROX index patterns within the first 48 hours of the therapy and high-flow nasal cannula success rates. The secondary aim was to determine other possible predictors of high-flow nasal cannula failure.

A cross-sectional study.

Patients admitted to the intensive care unit between April 2020 and January 2022 with coronavirus disease-19-related acute respiratory failure and treated with high-flow nasal cannula were included in the study. Patients’ demographics, clinical characteristics and laboratory findings at intensive care unit admission; ROX indices at initiation, 2^nd, 8^th, 12^th, 24^th and 48^th hours of high-flow nasal cannula; and outcomes were recorded.

In the study period, 69^th patients were managed with high-flow nasal cannula for at least 2 hours. While 24 patients (34.7%) were successfully weaned from high-flow nasal cannula, 45 (65.3%) patients failed. Overall mortality at day 28 was 44.9%. ROX indices were lower in the high-flow nasal cannula failure group through the 12^th, 24^th, and 48^th hours of the therapy, no significant change was observed (P = 0.33). While an overall increase in ROX index patterns were detected in patients weaned from high-flow nasal cannula (P = 0.002). Pairwise analyses revealed that ROX indexes remain stable during the first 8th hours in both groups, then improved to 12^th hours of the therapy in successfully high-flow nasal cannula-weaned patients.

Dynamic assessments of the ROX indexes could be more suggestive rather than a point assessment to identify patients who would benefit from the high-flow nasal cannula or deteriorate in coronavirus disease-19 related acute respiratory failure.