Second wave: Covid patients see rapid fall in oxygen level

Naina Mishra

Tribune News Service

Chandigarh, April 21

With a massive second wave of Covid-19 sweeping through the city, it has been observed that the oxygen level drops faster in patients once the saturation falls below 94 per cent.

Chandigarh Tribune spoke to Prof GD Puri, Dean (Academics) and Head, Department of Anaesthesia and Intensive Care, PGI, who explained the relation between blood oxygen level and Covid-19, and spoke about how to use the six-minute walk test for early detection.

Professor Puri said, “In the first surge of Covid, usually the pattern was that the saturation used to fall slowly in the initial phase even when a patient used to have saturation below 95 per cent. However, in the current surge, it has been seen that the fall is rapid once the saturation drops below 94 per cent.”

“In the present surge, we have seen patients’ saturation dropping from 94 per cent to 88 per cent within a few hours. This may be an indication of the cytokine storm, which the Covid virus elicits in the patients’ lungs and body,” said Professor Puri.

“Another difference we have found is that the recovery of such patients in whom the intervention is done at the right time is very quick. One of the reasons may be that these young individuals without any comorbid condition have better reserves and better healing power and timely intervention is helpful,” he said.

“Covid lung damage can result in decrease in the saturation as measured by the pulse oximeter. Normal individuals have 97-99 per cent saturation. Any decrease in the saturation is an indirect ‘reflectance’ of lung damage. If such patients can be detected early and the management started quickly, associated complications can be minimised and long-term outcome can be improved,” said Professor Puri.

Why is SpO2 (blood oxygen) important

It is now well-known that the Covid-19 virus affects the lungs adversely, which in turn can lead to decrease in partial pressure of oxygen in the blood. Reduction in blood oxygen (SpO2) can lead to more complications and hence tracking this level can be an early indicator of potentially serious implications.

Why pulse oximeter

• Pulse oximeter is a method of monitoring oxygen saturation of a Covid positive patient in the initial stages of the disease when the patient does not have any signs of breathlessness.
• Most Covid patients may be asymptomatic or mildly symptomatic but some subclinical pathology may be going on in them. Fever may make a person suspicious of some infection, simple monitors as pulse oxymeter can not only detect the lung involvement but also hint at early clinical deterioration.
• Normal oxygen saturation in blood as measured by finger pulse oximeter sensors is 96-100 per cent, depending upon the age and any chronic lung disease of patient.
• Any value less than 96 in an otherwise healthy adult should raise a suspicion of some underlying lung pathology

Six-minute walk test

• In Covid patients, oxygen saturation can drop on exercise or walking for six minutes
• Do sit and stand up for one minute and note saturation before and after finishing the exercise to detect severity of lung disease.
• Any drop in saturation more than 3% is significant
• If the baseline saturation in an adult falls below 95%, it hints at significant disease and patient should report to a hospital.