How and when to use oxygen cylinders and other equipment for COVID patients at home

The demand for equipment such as oxygen cylinders, concentrators and home ICUs is on the rise with the surge in cases. But should you really be using these at home?

Chennai-based freelance writer Divya Sainathan’s mother-in-law, R Gayathri, spent two weeks at the hospital for COVID treatment as she had 75% infection in both lungs. She needed 15 litres of oxygen per day at the time of her admission. It was brought down to 1 litre over two weeks. “At this point, we were asked to take her home, because the only service she needed at the hospital was oxygen. We were told to get an oxygen concentrator at home and monitor her SpO2 levels every two hours. If it fell below 92 for two hours, we were asked to take her back to the hospital. During her home care, we had to hire a nurse for constant monitoring,” she adds.

The nurse, who attends to the patient 24*7, monitors oxygen levels, adjusts the concentrator settings to taper off the supply, and helps the patient with other activities.

Gayathri is one among the many patients who are using a concentrator at home. With infrastructural and human resources being stretched thin in the wake of the brutal second wave of the pandemic, demand for home care equipment has gone up in recent times. Naturally though, many citizens are grappling to understand the basics of such usage. When does one start looking for oxygen cylinders or home ICU set-up or other homecare equipment? How do these work and where to procure these?

Oxygen cylinder, oxygen concentrators, home ICU support and home ventilators are some of the equipment that are in high demand as the explosion of COVID cases has made triaging and community level care an imperative. Here is an attempt to answer some of the most common questions that people may have about these.

What are oxygen cylinders and concentrators?

The coronavirus causes such damage to the lung that impacts its respiratory function: taking in oxygen and letting out carbon dioxide from the body. The membrane that transfers the oxygen and carbon dioxide is affected, leading to oxygen deficiency, which then has to be managed by an external oxygen administration system. Oxygen cylinders and concentrators make this possible, even in a home set up.


Read more: Not just a supply crunch: The real reason why patients in need of oxygen are suffering


An oxygen cylinder is simply a storage container from which oxygen is supplied to a patient through a surgical mask over the nasal cannula. The cylinders come in various capacities. Depending on the condition of the patient, the appropriate cylinder should be chosen. When the cylinder is exhausted, it should be refilled and used. 

“Generally, two types of cylinders are used for oxygen therapy. The B type cylinder has a water capacity of around 10 litres which can give approximately 1,200 litres of oxygen in gaseous form, The D type has a water capacity of around 46 litre, the gas capacity is approximately 7,000 litre,” says D Jagadesh Kumar, Biomedical Engineer at Rajiv Gandhi Government General Hospital, Chennai.

The water flask or humidifier that comes with the cylinder should be filled with normal tap water until the marked level and connected with a flowmeter. While these are basic guidelines for operation, users should reach out to the manufacturer for more detailed and specific guidelines on how to administer oxygen to a patient. Setting-up a cylinder requires some technical assistance which can be sought from the service provider.

Ocygen concentrator. Pic: Divya Sainathan

Oxygen concentrators, on the other hand, purify the oxygen in the atmospheric air and administer this filtered oxygen to the patient through a cannula. Ambient air contains 21% oxygen and 78% nitrogen, with other gases making up the remaining 1%. The concentrator takes in air from the atmosphere, filters it, releases the nitrogen back into the air and purifies the oxygen. The purified air, which is dispensed to the patient, is 90-95% pure. An oxygen concentrator with a capacity of 10 litre could cost anywhere between Rs 80,000 and Rs 90,000. It is a one-time investment. 

Through the pressure valve, the oxygen supply can be adjusted at flow rates ranging from 1 to 10 litre per minute. The supply should be set according to the patient’s clinical requirement. Unlike oxygen cylinders, concentrators need uninterrupted power supply for their operation. Even a power cut for a brief time period could impact the patient.

“Unlike oxygen cylinders, concentrators do not require routine manual intervention, except for filling up the water in the humidifier bottle and occasional replacement of air filters” adds Jagadesh.


Read more: Why are patients struggling to find hospital beds in Chennai?


When to use an oxygen cylinder or a concentrator?

In COVID, there are broadly two categories of patients: Patients who have tested positive for coronavirus infection and those suffering from long COVID (or COVID sequel), with residual lung damage.  

Among the two categories of patients, patients with long COVID may have respiratory problems even after recovery. “Such patients would need a steady amount of oxygen which can be managed with concentrators or oxygen cylinders at home,” says an internal medicine expert at a government hospital in Chennai.

“Oxygen therapy at home is useful for patients with long COVID, who have fewer chances of slipping into another major respiratory crisis. Only when a doctor has confirmed that chances of further worsening of condition are low, is it advisable to avail an oxygen concentrator or cylinder at home set-ups for COVID patients,” said the doctor. 

If a person has just tested positive and starts oxygen therapy at home, doctors say that it could, in fact, do more harm than good. “The oxygen levels are dynamic at this stage and the quantity of oxygen required also varies, hence oxygen therapy for such patients at home is not advisable. It could be used as a stop-gap measure only if the patient will be shifted to a hospital within a short span of time,” another government doctor based in Chennai adds. 

Besides COVID, concentrators are suggested for long-time usage by persons with respiratory illnesses that require regular oxygen supply. For patients on concentrators, doctors advise having a full-time nurse for monitoring the saturation levels and adjusting the concentrators.

If the saturation level drops below 95 for normal patients (and below 90 for asthmatics and smokers), they will need supplemental oxygen. “It is essential to monitor the oxygen saturation from time to time. If it falls below 95, it is advisable to seek an oxygen bed at a hospital and not rely on home oxygen therapy,” adds the doctor.

It is risky to use oxygen at home if the saturation is below 95; it can do more damage than good. It can be used, but not advisable for early COVID.

Doctors exercise caution against setting up ICUs at home as it requires constant monitoring. Pic: Churehill/ Creative Commons Attribution-Share Alike 4.0 International

Buying oxygen cylinders and concentrators

Here’s a list of volunteer organisations that provide information on places to procure oxygen cylinders from:

People can reach out to them on Twitter and seek help. While buying/renting oxygen cylinders, it is essential to keep the following points in mind:

  • Colour code: The body of the oxygen cylinder is black and the shoulder is white
  • Ensure that you get the humidifier, flow adjuster, tubing meter and flow meter along with the cylinder

As oxygen causes other materials to burn rapidly, it is essential to keep the cylinder away from heat sources and flames, secure the valve properly to prevent leakage , ensure adequate ventilation and turn off the valve when required.


Read more: Don’t let your desperation during COVID times make you fall for such scams


Oxygen concentrators may be bought online, on e-commerce platforms like Amazon or Flipkart, but the real crunch is supply, as there are not enough domestic manufacturers to meet the demand that exists under the current circumstances. It is a market largely supplied by imports. A recent press release from the government says that individuals can now acquire oxygen concentrators from abroad for personal use, through post, courier or e-commerce portals, in the list of exempted categories, where customs clearance is to be sought as ”gifts”. This exemption is valid till July 31 2021.

It is however important to consult a medical professional before making a purchase, and seek inputs about the type of concentrator that would be suitable for the patient.

There are home ICU and ventilator suppliers. Can one avail this facility if they do not get an ICU bed at hospitals?

Medical practitioners are strictly against this practice. ICUs are meant only to be set-up at hospitals as it requires intensive monitoring. A staff nurse, available round the clock, would keep a check on the patient’s oxygen levels, urine output, adverse reactions caused by drugs, monitoring for new symptoms and what contributes to it. Similarly, critical patients are put on a ventilator. A ventilator is a device that provides oxygen to lungs through a breathing tube.

“Home ICUs and ventilators should not be set up as they need extensive equipment and continuous care, which cannot be provided at home. It is only safe to treat critical patients in a hospital set-up,” adds the government doctor. 

Former director of public health, Dr K Kolandaswamy says, “Even if manufacturers are providing home ICUs and ventilators, it is not right to avail the services at home as these are meant only for hospital uses. It also leads to inequity in treatment of patients.”

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