By Rachel V. Thomas New Delhi, April 26 : Sushila Verma, a 45-year-old housewife in the capital, who tested Covid positive recently, had developed breathing troubles. The pulse oximeter showed her oxygen levels going below 90. While the family scouted for hospitals, her neighbour helped her breathe again with an oxygen concentrator. Her oxygen levels have now reached a healthy 96. The second Covid wave, which began hitting India in March this year, has left more patients gasping for breath. The severe breathlessness has been a common feature observed this time that has led to a spike in demand for oxygen. The surge in demand, observed in many states including Delhi, Haryana, Gujarat, Madhya Pradesh and Maharashtra, led to acute shortage of oxygen in the country, with many hospitals sending SOS messages. Lack of oxygen support has also led to several deaths in the national capital. At this juncture, oxygen concentrators have become a necessity. Concentrators are a small device supplying supplementary oxygen-enriched air to people requiring oxygen therapy. They are generally used for patients with lung and other respiratory diseases. "In the case of Covid-19 patients, who feel breathless when their oxygen saturation drops below 94 per cent, then he or she must be put on Oxygen Therapy immediately to avoid damage to other body parts. Oxygen concentrators play an important role as they supply supplemental oxygen to patients via nasal cannula," Sunil Khurana, MD and CEO at BPL Medical Technologies in New Delhi, told IANS. "Oxygen concentrators work like the air conditioning machine. It takes the oxygen from the air, modifies it and releases it in a different form. Oxygen concentrators concentrate the ambient oxygen," added Dr Ravi Shekhar Jha, HOD and Senior Consultant Pulmonology, Fortis Escorts Hospital, Faridabad. How does these machines work? An oxygen concentrator is an electronically operated device that separates oxygen from room air. It provides high concentration of oxygen directly to you through a nasal cannula. "Clinical studies have documented that oxygen concentrators are therapeutically equivalent to other types of oxygen delivery systems," Khurana said. Oxygen concentrators are widely used for oxygen provision in healthcare applications, especially where liquid or pressurised oxygen is too dangerous or inconvenient, such as in homes or in portable clinics. "They work on the principle of 'rapid pressure swing absorption' which is where the nitrogen is removed from the air using zeolite minerals which absorb the nitrogen, leaving the other gases to pass through and leaving oxygen as the primary gas. Once the oxygen is collected, the pressure then drops which allows nitrogen to desorb and be expelled back into the air through silencers," Khurana explained. Oxygen concentrators are portable and easy to use, and are thus better than the oxygen cylinders. Although at Rs 40,000-Rs 90,000, they are more expensive than cylinders (Rs 8,000-20,000), they require very minimal maintenance. The only maintenance cost is power consumption and the disposable filters and sieve beds that need to be replaced over years of usage, Khurana said. While oxygen concentrator devices can be used at the convenience of patients under the supervision of doctors or healthcare workers, the stand-alone cylinder needs to be refilled and needs utmost care and monitoring as there are chances of leakage and can cause fire accidents. "Oxygen concentrators do not have limitations of refilling. It takes oxygen from air itself, which enables unlimited supply of oxygen till electricity is available. Oxygen concentrator is a more safe option compared to the Oxygen cylinders, because cylinders can sometimes leak and oxygen saturation increases the risk of fire," Jha told IANS. Oxygen concentrators produce up to 95 per cent pure oxygen. It also has in-built oxygen sensors which can indicate if purity levels go down, Khuranna said. While the total market size in India is 40,000 units, the sudden peak in demand is likely going to affect the quality as there are not enough manufacturers in the country. "Most of the devices are manufactured in China and part of raw material is manufactured in the US. India Inc was never prepared to cater to this huge surge in demand," Khuranna said. (Rachel V Thomas can be reached at rachel.t@ians.in) /IANS