Police have launched a campaign in housing complexes and standalone highrises as part of their Covid battle, telling residents to monitor their blood oxygen saturation level at least once a day with a pulse oximeter.

Officers from respective police stations have been using loud hailers since Sunday night to try and persuade residents to keep tabs on their blood oxygen saturation level, which can drop in persons infected by the coronavirus that causes Covid-19.

Officers said leaflets containing information on how to use pulse oximeters and when to contact health officials would be distributed to the residents.

“Our main targets are senior citizens with comorbidities, which include ailments of the lungs, heart and kidneys,” an officer said.

Doctors said pulse oximetry was a test of how well oxygen was being sent to parts of the body farthest from the heart, such as the arms and the legs.

An oximeter is a small device that gets attached to the fingertip and sends out two wavelengths of light to measure the oxygen saturation level in the blood and the pulse rate. The price varies between Rs 800 and Rs 3,000.

“The pulse oximeter makes it easier to detect the progression of a patient's health from the early stage of attack to stage II and III and helps a doctor decide whether the person needs hospitalisation or not,” said Amitabha Nandy, the director of the Centre for Studies on Infection and Immunity and a specialist in tropical diseases.

“Monitoring oxygen levels therefore remains very vital for Covid-19 treatment.”

Health department officials said that over the past two-and-a-half weeks, an increasing number of Covid-19 cases were being reported from housing estates and standalone highrises. Many of them are located on Prince Anwar Shah Road and in Jodhpur Park, Bhowanipore, Alipore, Tollygunge and Ballygunge.

“We received a communication from the home department about use of pulse oximeter on Saturday. The thrust was on residents of housing complexes and standalone multistoried buildings,” said a senior officer at Lalbazar. “The police commissioner has accordingly instructed all divisional deputy commissioners to start this campaign.”

“If there is any fluctuation in the health of any of the residents, the family can immediately call up the local police station and seek help,” said an officer of Ballygunge police station.