Indian Space Research Organisation has designed a portable Medical Oxygen Concentrator named ‘SHWAAS’. The oxygen concentrator is developed by ISRO’s lead centre of research, Vikram Sarabhai Space Centre. The medical oxygen concentrator can deliver an enhanced level of oxygen (over 95%) than in air to support patients with respiratory illness or who are on oxygen therapy. It selectively separates the nitrogen gas from ambient air through Pressure Swing Adsorption (PSA) to increase the oxygen gas content. The device can continuously supply @10 LPM enriched oxygen adequate for two patients at a time.
Pressure swing adsorption (PSA) is a technology that is used to separate some gas species from a mixture of gases under pressure. Oxygen level is measured by SpO2 levels, which is also known as oxygen saturation. It is a measure of the amount of oxygen-carrying haemoglobin in the blood. A healthy individual with normal lungs will have an arterial oxygen saturation that ranges between 95% – 100%.
‘SHWAAS’, ISRO’s medical oxygen concentrator has a rated power of 600 Watt with an operating voltage of 220V/50 Hz. The oxygen flow in the device is controllable and ranges between 0.5 to 10 litres per minute. This concentrator has 2 oxygen outlets with a minimum of 82% oxygen concentration. The outlet oxygen pressure of the concentrator ranges from 50-80 kPA. It also has an audible alarm to maintain the pressure and flow rate of oxygen. This medical oxygen concentrator weighs around 44 kg and has dimensions of 600 mm H x 500 mm L x 400 mm W.
Atmospheric air constitutes about 78% nitrogen and 21% oxygen. Oxygen concentrators help in increasing the oxygen concentration, by filtering out and throwing away nitrogen. The functioning of oxygen concentrators is quite similar to the functioning of oxygen tanks and cylinders. A notable difference is that, while the cylinders need to be refilled, the oxygen concentrators can work 24 x 7.
Professor and Head of Department Anaesthesia, B. J. Medical College, Pune, Prof. Sanyogita Naik informed that, “Oxygen concentrators can be used only in moderate cases of COVID-19 when the patient experiences a drop in oxygen levels, where the oxygen requirement is a maximum of 5 litres per minute.” She also mentioned that oxygen concentrators are very useful for patients experiencing post-COVID complications.
Dr Chaitanya H. Balakrishnan, Covid Co-ordinator, St. John’s Medical College Hospital, Bangalore informed that using oxygen concentrators without medical guidance can be very harmful. He further added, “Patients with moderate pneumonia induced by COVID-19 – with oxygen saturation less than 94 – can benefit from supplemental oxygen given through oxygen concentrator, but only till they get hospital admission. However, patients using it themselves without suitable medical advice can be harmful.”