Predictive ability of ROX index, ROX-HR and HACOR Scale for High Flow Nasal Cannula Failure in Patients with Acute Hypoxemic Respiratory Failure: A Prospective Observational Study

Acute hypoxemic respiratory failure is one of the most common life-threatening conditions that  warrants immediate medical attention and intensive care admission, with substantial morbidity and  mortality. Of late, there is an increasing usage of the high flow nasal cannula as a primary mode  of oxygenation in patients with acute hypoxemic respiratory failure, bolstered by recent evidence  that demonstrated reduced rates of intubation and invasive mechanical ventilation, with possibly  reduced mortality. It has emerged as an alternative to non-invasive mechanical ventilation due to  its reported advantages of better patient comfort, tolerability, improved oxygenation parameters  and decreased work of breathing in respiratory failure. However, it is also widely known that delay  in intubation and institution of invasive mechanical ventilation may worsen patient outcomes in  acute hypoxemic respiratory failure. No clear recommendations or criteria have been established  to identify the patients who need invasive mechanical ventilation. Hence, there is a need to identify  characteristics that can predict failure of high flow nasal cannula therapy, so that such subset of  patients may be monitored strictly and kept under consideration for early endotracheal intubation,  which may potentially improve patient outcomes.

The ROX index, ROX-HR and the HACOR scale are some of the novel indices that have been  demonstrated to predict the failure of high flow nasal cannula therapy. These values are obtained  from commonly measured bedside parameters. However, the evidence is scant and needs more  validation.

This study will be a prospective observational study conducted in the Medical- Surgical intensive  care unit of Sir Ganga Ram Hospital, New Delhi. We plan to recruit approximately 80 subjects in  this study and aim to test the ability of these three indices to predict the failure of high flow nasal  cannula therapy when used as the primary mode of oxygenation in the first 12 hours of initiation