What is the Mumbai 02 model and how it cracked the code
When the worst surge in infections amid the second Covid-19 wave triggered oxygen shortage across the country, Mumbai fell back upon 15 big and 11 smaller Liquid Medical Oxygen [LMO] tanks installed at six hospitals and as many jumbo Covid-19 centres between May and June last year. The tanks helped meet the daily demand for medical oxygen that went up from 210 metric tonnes (MT) in the first wave to 270 (MT) last month.
“Building the additional LMO tanks helped us cope during the second wave,” additional municipal commissioner P Velrasu said.
The success in coping prompted the Supreme Court on Wednesday to ask the Centre and the Delhi government to examine the “Mumbai model” of optimal utilisation of oxygen. It said the Delhi government should consider replicating this model as Mumbai has also made arrangements for buffer storage.
Velrasu said the tanks, their construction, fitting, and piping, cost them over ₹14 crore. “At that point, we did not know if they would be utilised, but we still went ahead and created that infrastructure.”
LMO tanks are highly pressurised and installed on reinforced concrete structures. They require certification by the Petroleum and Explosives Safety Organisation under the ministry of commerce and industry, which has been overseeing the supply and distribution of oxygen during the crisis.
The Brihanmumbai Municipal Corporation (BMC), Mumbai’s civic body, plans to build 10 more LMOs in preparation for a possible third wave expected anytime between July and September.
In April, when the city’s daily average cases touched 7,786, many patients were shifted from one hospital to another due to a shortfall of oxygen. For instance, 168 patients were alone moved out of six government hospitals to jumbo centres on April 17 after oxygen supply was affected.
The BMC has announced the appointment of six officials for coordination between oxygen suppliers, assistant municipal commissioners of the 24 civic wards, and the Food and Drug Administration. The officials will be responsible for maintaining the existing oxygen supplies and ensuring they are used sparingly.
Civic officials said they have also ensured the safe transportation of oxygen cylinders. Only two BMC-run hospitals, Kasturba Hospital and HBT Trauma Care, have oxygen generation plants. Other big hospitals have LMO tanks, which are refilled at least once daily. Other hospitals rely on oxygen cylinders. All hospitals are mandated to keep cylinders as a backup. When the crisis hit, the civic body deployed six quick response vehicles to ferry cylinders and concentrators to hospitals in need.
“Ward-level teams were formed to coordinate and move surplus oxygen from one site to another...,” said Krishna H Perekar, BMC’s chief engineer.
Officials said a resource inventory of oxygen use and infrastructure at hospitals proved helpful. Oxygen was often supplied to suburbs such as Navi Mumbai and Thane. “Our inventory has micro-details like the number of jumbo oxygen cylinders, dura cylinders, and capacity of the LMO tanks at all hospitals. We also have exact details of the oxygen usage at each hospital,” Velrasu said. “We formed crack teams to ensure that the LMO tanks reach Mumbai smoothly. These teams were also deployed at the cylinder refilling plant at Navi Mumbai to ensure that Mumbai gets its quota of cylinders.”
At the peak of the oxygen demand, Mumbai faced a shortfall of 15 to 20MT oxygen. This was managed by moving surplus stock from one place to another and seeking oxygen from Gujarat.
Maharashtra’s Covid-19 task force also recommended that doctors should stop the use of High Flow Nasal Cannula (HNFC) to deliver oxygen (up to 80 litres/min) when the demand increased last month. Hospitals were encouraged to use Bilevel Positive Airway Pressure (BiPAP) machines, which deliver oxygen either through a flowmeter (up to 15 litres/min) or a non-invasive ventilator (up to 30 litres/min), and with lower pressure.
“Soon after the advisory, we completely stopped use of HNFC and alternatively started using non-invasive ventilation such as BiPAP,” said Dr Ramesh Bharmal, dean of BMC-run Nair Hospital.
Dr Gautam Bhansali of the Bombay Hospital said that they reduced the use of HNFC too. “It is hard to completely stop its use because most patients are comfortable with the nasal cannula. With the BiPAP, we have to use a face mask which some patients find uncomfortable.”
The BMC plans to set up 16 oxygen generation plants at 12 hospitals to reduce the dependence on LMO and cylinders. “We may still require LMOs as they provide better pressure, mainly for patients in the Intensive Care Units,” said Velrasu. “But having oxygen plants at all facilities will reduce the dependency to a large extent.”
On Thursday, the Bombay high court said BMC chief Iqbal Chahal should hold a video conference with other municipal bodies and explain how the city managed the second wave.