RETROSPECTIVE ANALYSIS OF ROX INDEX IN ASSESSING THE OUTCOME OF HIGH FLOW NASAL CANULA DURING FIRST AND SECOND WAVE OF COVID 19 IN A LOWER MIDDLE-INCOME COUNTRY

PURPOSE -
In the SARS covid-19 pandemic era, use of high flow nasal canula (HFNC) was the dictum prior to employing invasive mechanical ventilation. The second wave of the pandemic in India saw the emergence of the delta variant which further accelerated the use of HFNC. There is a need to develop an objective index namely the respiratory oxygenation index (ROX) to qualitatively assess the outcome of HFNC during the first and second waves to understand the pattern of virulence between different variants of the virus.
MATERIALS AND METHODS –
This is a retrospective observational study documenting the ROX index at 6 and 12 hours respectively during first and second waves of covid-19. The values of ROX index were compared with the final outcome of the patient to determine success (switching to nasal prongs) or failure (need for NIV, intubation or death) of HFNC as mapped by the receiver operating characteristic curve.
RESULTS –
The ROX index was found to have higher predictive nature at 12 hours from initiation of HFNC and greater cut-offs during the second wave (5.23) of the covid-19 as compared to the first wave (4.88)
CONCLUSIONS –
This study substantiates on the fact that greater ROX index cut-offs, worse outcomes with HFNC use and augmented need for intubation in the delta strain versus the alpha strain accounts for greater virulence of the delta variant in the second wave.