High Resolution Computed Tomography of Thorax- Is it an Early Predictor of Hypoxaemia in COVID-19 Patients?

Introduction: Novel Coronavirus-2019 (nCoV-2019) is capable of human-to-human transmission and can lead to acute respiratory distress syndrome similar to Middle East Respiratory Syndrome (MERS) due to lung parenchyma destruction Some patients with COVID-19 consistently demonstrated no hypoxaemia, however, some patients develop sense of difficulty in breathing due to increased airway resistance Aim: To assess the potential of High Resolution Computed Tomography (HRCT) thorax as an early predictor of hypoxaemia in COVID-19 patients Materials and Methods: A prospective longitudinal cohort study of 1000 Reverse Transcription Polymerase Chain Reaction (RT-PCR) confirmed COVID-19 and HRCT thorax positive patients, who were monitored simultaneously for SpO(2) levels, were undertaken HRCT findings were graded into Computerised Tomography Severity Index (CTSI) and correlated with patient's SpO(2) levels, at the time of scan on admission Patients, who had normal SpO(2) levels (>= 95%) at the time of initial scan, were monitored upto five days Pearson's correlation test was used to find correlation between CTSI and SpO(2) levels Results: In present study group there was male predominance (4:1) Fever was the most common clinical presentation followed by cough HRCT thorax features were categorised as Typical 769 (76 9%), Indeterminate 176 (17 6%) and atypical 55 (5 5%) 371 (82 8%) patients with SpO(2) >95% were having CTSI between 0-7, similarly 189 (54 4%) patients with SpO(2) 90-94% were having CTSI between 8-15 and 133 (64 8%) patients with SpO(2) = 95%, 90-94% and <90%, respectively Statistical correlation between CTSI and SpO(2) levels at the time of initial scan was significant (Pearson's correlation coefficient (r)=-0 261 and p-value <0 01) Number of patients who developed hypoxaemia (SpO(2) <95%) on follow-up in CTSI Category 1, 2 and 3 were 42 (11 32%), 10 15 87%) and 2 (14 28%), respectively The association between CTSI and development of hypoxaemia based on follow-up SpO(2) levels was statistically found to be insignificant (chi-square value=1 21, degree of freedom (d f ) 2 and p-value=0 570) Conclusion: In present study group, a negative correlation was established between CTSI and SpO(2) levels The association between CTSI and development of hypoxaemia on follow-up SpO(2) monitoring was found to be non-significant statistically So, HRCT thorax cannot be relied upon as an early predictor of hypoxaemia in COVID-19 patients