Early Detection of Silent Hypoxia in Covid-19 Pneumonia Using Smartphone Pulse Oximetry

The coronavirus 2019 (COVID-19) disease caused by the severe acute respiratory syndrome coronavirus 2 (SARSCoV-2), which was first reported in the city of Wuhan, China in late December 2019, has since become a global pandemic by March 2020 (WHO). There are now more than 2.6 million cases of COVID-19 affecting 210 countries and territories resulting in more than 183,000 deaths as of 22 April 2020 (Worldometer Report). The International Monetary Fund estimates that COVID-19 will cause USD $9 trillion in global GDP losses leading to the worst economic downturn since the Great Depression (IMF). Writing in the New York Times on 20 April 2020, Dr. Richard Levitan, an intubation specialist, highlighted that a significant number of hospital admissions not due to COVID-19 were actually found to be suffering from pneumonia due to COVID-19 upon having their chest x-rays taken [1], most with severely low oxygen saturation levels of only 50%. He pointed out that unlike normal pneumonia, in which patients will feel chest pain and significant breathing difficulties, initially COVID-19 pneumonia causes oxygen deprivation that is difficult to detect since the patients do not experience any noticeable breathing difficulties, hence causing a condition which he terms as “silent” hypoxia. By the time COVID-19 patients realize they are short of breath, their conditions have already significantly deteriorated into moderate-to-severe levels of pneumonia. Analysis of COVID-19 pneumonia patients revealed that the virus initially attacks the lungs in a different way. The air sacs in COVID-19 patients’ lungs do not fill with fluid or pus as in normal pneumonia infections but rather the virus only causes the air sacs to collapse, thereby reducing the