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Workings of a Pulse Oximeter

Recently an article was published in the edition of ‘The Hindu’ on July 19, 2020. Divya Kala Bhavani, the contributor, observed, “People with COVID-19 often need oxygenation support.

Therefore, Pulse Oximeter, a staple for many doctors, has become something of a necessity for the layperson. Oximeters have been flying off the shelves for many households’ first aid kits, largely because they are non-invasive, low-cost, easy to use, and effective at detecting hypoxemia (low blood oxygen levels).” More than a month later the device is flying-off the shelves in no time.

She adds further, “There are two important readings: the pulse rate, recorded as beats per minute (60 to 100 is the safe range); and the oxygen saturation of haemoglobin in arterial blood, the reading of which is recorded as SpO2). Normal readings range from 95% to 100%; anything less, and the user should get medical assistance from a doctor. If your oximeter has alarms, atypical readings will set them off.” On a number of occasions while serving our members, we at Porosh, have first-hand experience that timely medical intervention based on oximeter readings saved a few seniors’ lives.

“The mechanism clips onto the user’s forefinger, though some oximeters have been known to be clipped onto one’s big toe or even the ear, depending on the model. According to the World Health Organization’s Pulse Oximetry Training Manual, one must use the oximeter with patience. Once clipped on, it requires about 10 seconds to get an accurate reading,” Divya contends. “One cannot use the pulse oximeter as a sole detector for any respiratory issues. It is only meant to give readings for a small time interval. When buying an oximeter, one must be wary of the brand names.”

There are oximeters selling on e-commerce platforms that will work for a month at most before giving out, and may cost as much as about ₹2,000.


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