NHS chiefs have dispatched emergency engineers to test oxygen flow capacity in hospitals amid fears that trusts cannot provide enough of the medical gas for coronavirus patients.
The measures follow the declaration of a critical incident at Watford General Hospital on Saturday when oxygen delivery nearly failed.
On Wednesday night, leading critical care doctors warned that NHS planners had been caught off guard by the higher than expected proportion of patients, including Boris Johnson, who require oxygen despite not being ill enough to need a ventilator.
Many of these are treated on general wards, where the piping is often more rudimentary, rather than in intensive care units.
Dr Alison Pittard, Dean of the Faculty of Intensive Care Medicine, told The Telegraph that coronavirus patients may have to be transferred between hospitals in order not to exhaust supply.
“No one could have predicted that this would have been such an issue,” she said. “We believe that enough oxygen is getting to hospitals, but the problem we have now is getting it distributed within the hospital to the beds that need it. We have to keep pressure at a safe level in the system.”
Increasing numbers of people are being put on Continuous Positive Airway Pressure (CPAP) machines, which can demand 50 litres of oxygen per minute for a single patient.
Dr Tom Lawton, a Bradford-based critical care consultant, said his hospital could provide 3,000 litres per minute.
“If you’re using 50 litres per minute for each patient, then that’s suddenly only five on a ward and 60 in a hospital – and we need more than that,” he told the BBC. “It’s not just us, it’s also hospitals around the country – they weren’t designed for this level of oxygen use.”
Dr Nick Scriven, the president of the Society for Acute Medicine, said oxygen delivery issues are likely to be worse in smaller hospitals and those built 10 or more years ago.
“A lot of devices we are using to keep people out of ICU [intensive care] use a huge amount of oxygen, and if your pipework is smaller that can be an important factor,” he said. “Smaller, older hospitals in London could be vulnerable.”
On Saturday, Watford General Hospital issued a statement warning everyone other than pregnant women to stay away after the oxygen system came close to breaking down due to high demand from Covid-19 patients.
Most hospitals are supplied by a single large cylinder of extremely cold liquid oxygen, which must be converted into gas before entering the piping delivery system. Only a limited amount of liquid oxygen can be converted each minute, however.
Some patients requiring high volumes of non-invasive oxygen support, such as from CPAP machines, are treated in intensive care, while others remain on general Covid-19 wards, with procedures differing by trust.