Lung India (Jan 2022)

Silent Hypoxia in Coronavirus disease-2019: Is it more dangerous? -A retrospective cohort study

  • Prashant Sirohiya,
  • Arunmozhimaran Elavarasi,
  • Hari Krishna Raju Sagiraju,
  • Madhusmita Baruah,
  • Nishkarsh Gupta,
  • Rohit Kumar Garg,
  • Saurav Sekhar Paul,
  • Brajesh Kumar Ratre,
  • Ram Singh,
  • Balbir Kumar,
  • Saurabh Vig,
  • Anuja Pandit,
  • Abhishek Kumar,
  • Rakesh Garg,
  • Ved Prakash Meena,
  • Saurabh Mittal,
  • Saurabh Pahuja,
  • Nupur Das,
  • Tanima Dwivedi,
  • Ritu Gupta,
  • Sunil Kumar,
  • Manisha Pandey,
  • Abhinav Mishra,
  • Karanvir Singh Matharoo,
  • Anant Mohan,
  • Randeep Guleria,
  • Sushma Bhatnagar

DOI
https://doi.org/10.4103/lungindia.lungindia_601_21
Journal volume & issue
Vol. 39, no. 3
pp. 247 – 253

Abstract

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Background: Hypoxia in patients with COVID-19 is one of the strongest predictors of mortality. Silent hypoxia is characterised by the presence of hypoxia without dyspnoea. Silent hypoxia has been shown to affect the outcome in previous studies. Methods: This was a retrospective study of a cohort of patients with SARS-CoV-2 infection who were hypoxic at presentation. Clinical, laboratory and treatment parameters in patients with silent hypoxia and dyspnoeic hypoxia were compared. Multivariate logistic regression models were fitted to identify the factors predicting mortality. Results: Among 2080 patients with COVID-19 admitted to our hospital, 811 patients were hypoxic with SpO2 <94% at the time of presentation. Among them, 174 (21.45%) did not have dyspnoea since the onset of COVID-19 symptoms. Further, 5.2% of patients were completely asymptomatic for COVID-19 and were found to be hypoxic only on pulse oximetry. The case fatality rate in patients with silent hypoxia was 45.4% as compared to 40.03% in dyspnoeic hypoxic patients (P = 0.202). The odds ratio of death was 1.1 (95% CI: 0.41–2.97) in the patients with silent hypoxia after adjusting for baseline characteristics, laboratory parameters, treatment and in-hospital complications, which did not reach statistical significance (P = 0.851). Conclusion: Silent hypoxia may be the only presenting feature of COVID-19. As the case fatality rate is comparable between silent and dyspnoeic hypoxia, it should be recognised early and treated as aggressively. Because home isolation is recommended in patients with COVID-19, it is essential to use pulse oximetry in the home setting to identify these patients.

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