Gangtok: While the rest of the country is struggling to procure liquid oxygen, Sikkim can never procure liquid oxygen. It sounds alarming, but the alarm rings for logistics of bringing a tanker of liquid oxygen to Sikkim. The hilly terrain of Sikkim is to be blamed, as a tanker full of liquid oxygen could end up being catastrophic if met with an accident of any kind in the hilly terrain. On most occasions, companies and distributors are not even issued a license to ferry liquid oxygen to the hills. But liquid oxygen is preferred as it is cheaper, also the oxygen it generates has a purity rate of 99%.
So how does Sikkim procure oxygen? STNM Hospital initiated its own Volume Swing Absorption Oxygen Plant on October 9, 2020. The project was in the plans ever since the new STNM Hospital started functioning in 2019. Now, what is unique about STNM’s oxygen plant is that it retrieves oxygen from the atmosphere, then extracts and feeds the oxygen to the oxygen plant. The same is in practice in Central Referral Hospital (CRH) in Sikkim, as ideally, the atmosphere in Sikkim is cleaner and extraction becomes easier.
While STNM Medical Superintendent KB Gurung was exhibiting the oxygen plant on April 22, EastMojo caught up with the Hospital’s BioMedical Engineer, Ravi Chauhan.
But how can we retrieve oxygen from the atmosphere?
There is nitrogen in abundance in the atmosphere along with oxygen, so Sieve Cells extract the nitrogen. The plant runs in the blower system and not a compressor system. The blower swings both clockwise and anti-clockwise, hence the double sound. When it sucks the air on one side, the Sieve Cells extract the nitrogen, after which the air is left with only oxygen being drawn to a small chamber, where it has an oil-free compressor which will push the oxygen which then goes to the manifold. There it gets mixed with the cylinder and then it reaches the patients.
Is there a need for extra oxygen for COVID patients?
For COVID patients there is generally 4 to 5 times more oxygen needed. When it is given to a normal patient it is controlled by the flowmeter, but when being given to a COVID patient, it has to be given in full. COVID patients get around 40-60 litres of oxygen per minute. That is almost a four-time increase. In the main hospital, 732 beds are oxygen connected. The COVID devoted Hospital inside STNM premises has between 107 to 125 beds, of which there are 77 oxygen connected beds.
So where does oxygen come from for COVID hospital?
In a COVID building, there is a different system for bedside oxygen supply. It is termed as ‘SB system’ and it has a double locking system. Different countries have different standards, but here in STNM, initially, the COVID Hospital was supposed to be the Chest and Respiratory Wing of the Hospital. So, when the construction of the building was going on, the pipeline for oxygen was already laid. Now, with the double locking system, inserting and removing has some hassle. We teach the staff how to carry out but when the staff changes weekly due to COVID, it becomes a problem. All the rooms in the COVID hospital are isolated as per the blueprint for Chest and Respiratory Hospital. It is a 12-meter cube per hour connection for the COVID Hospital.
Is that sufficient and pure oxygen?
The Volume Swing Absorption system plant that we have, gives 4-5 times more supply than a compressed cylinder system. That is more than 3 times the maximum consumption in STNM Hospital. We have a plant that gives a 30-metre cube per hour oxygen supply. In the hospital, the need is maximum of 20-metre cube per hour consumption. Our plant gives 10-metre cube per hour extra oxygen. We have that much supply. Our Oxygen Plant doesn’t need any consumable just as liquid oxygens in the plains, there is no need for raw materials, it can extract oxygen from the air. Our atmospheric pressure plant generates with 93% purity. If the air is cleaner as in Sikkim it generates 96% pure oxygen. It may drop down to 90% purity as it fluctuates as per the atmosphere.
If the plant fails, what alternative do we have?
Compressed oxygen comes in cylinders, which we retrieve and refill from Siliguri, West Bengal. In Sikkim, we do not have compressed oxygen of medical standard, it can be used in industries. Hence, we retrieve from a distributor in Siliguri, same as Central Referral Hospital here. Those compressed oxygen cylinders are kept in the hospital’s manifold which connects D type cylinders with the central oxygen pipeline. The D type cylinders have 47 litres of oxygen per cylinder and there are 260 jumbo cylinders, some of which have gone for a refill, some are in transit, some are connected to the pipeline, while others are kept as buffers. Here in Sikkim, we use B and D type. B type cylinders with 10 litres supply are given in the wards in case of emergency, which is looked after by the Health Department’s Stores section. We have around 101 B type cylinders in STNM Hospital and another 100 cylinders have been approved for procurement by the government, 25 of which have been delivered. In the hospital, there are 126 B type cylinders. But only D type cylinders are looked after by STNM Hospital.
But if we cannot retrieve cylinders from Siliguri?
Previously, STNM Hospital, Singtam and even Namchi district hospital used to ferry oxygen cylinders, including refill from an oxygen plant in Makha near Singtam, East Sikkim. But it was troubled by the irregular electric power supply, wherein if there was no electricity in Singtam, the oxygen cylinders could not be refilled. For the old STNM Hospital, it was not much of a problem. But for the new 1000 bedded STNM Hospital, it became a problem. Sometimes, we borrowed from Central Referral Hospital, which has a plant. They have a similar atmospheric plant, but when that got spoiled, we had to rely on each other. Then, CRH started getting cylinders from a distributor in Siliguri. When we started facing a lot of shortage, we started refilling from Siliguri. If they fall short on distribution now, we have our own plant as a backup along with an upcoming Pressure Swing Absorption System Oxygen Plant given by the Union Health Ministry.
How much oxygen can be supplied from Pressure Swing Absorption System Oxygen Plant?
This plant is being given especially by the Union Health Ministry as part of COVID-19. The oxygen plant also takes oxygen from the air. If our plant can give 500 litres per minute at maximum, the Pressure Swing Absorption System can give 200 litres per minute. It will come to the State by April 30. Installation may take a week to 10 days and by Mid May we will have a third source of oxygen.
Will all of these oxygens be channelled somewhere?
If the oxygen generated only from the plant is given, the height of the main hospital building at 9 floors, by the time it reaches the top from the ground floor, it develops air pressure difference. The Manifold system gets the compressed oxygen cylinders connection with the patients, bedside which has 4 air outlets. We can give around 67-metre cube per hour of supply in full capacity. Before the COVID-19 spread, when we did not have a plant, we had around 20-25 cylinders consumption per day, which is an average of one cylinder per hour in the main hospital. When we shut down the plant for three days for maintenance, it increased to 100-120 cylinders per day for COVID patients. After the plant was constructed, the consumption from the cylinders has dropped by two-thirds. If it was 100 cylinders before, now with the oxygen from the plant, the consumption of cylinders has come down to mere 25-30 cylinders.
How many different lines of oxygen reach the patient?
There are 4 kinds of oxygen for the patients. Oxygen, nitrous come with cylinders and it is used as anaesthetics. Then comes medical air, and lastly vacuum. If you go to the ICU, there are four pods for those four kinds. We have 85 ventilators, some of which may not be functional, as they have technical glitches which are bound to arise. We are trying to procure more. There are ventilators in Operation Theatres (OT), but during COVID, when general ICUs and OTs didn’t function, some of the batteries of these ventilators died. We are trying to procure, OTs with 4 lines, ICUs with 3 lines and wards with 2 lines. OT needs anaesthesia and nitrous, but in ICUs, they do not need nitrous.
Does that mean oxygen is diluted in different lines?
Dilution of oxygen is necessary. When in need of ventilator support, more than 90% purity is good enough. No doctor gives 100% oxygen, they have to dilute it for which they have medical air. When there is an operation going on, they dilute medical air and oxygen. Medical air is compressed filter air, used for the ventilator, and it is used for dilution. Normal air has the potential to spoil equipment as it may have dust particles. Sometimes there may be technical glitches in the washer if sometimes the nurses do not insert them properly.