Less invasive oxygen may be better than ventilators

British and American intensive care doctors at the front line of the coronavirus crisis are starting to question the aggressive use of ventilators for treating patients.

In many cases they say the machines, which are highly invasive and require the patient to be rendered unconscious, are being used too early and may cause more harm than good. Instead they are finding that less invasive forms of oxygen treatment through face masks or nasal cannulas work better for patients, even those with very low blood oxygen readings.

Dr Ron Daniels, a consultant in critical care at University Hospitals Birmingham NHS Foundation Trust, yesterday confirmed reports from US medics that he and other NHS doctors were revising their view of when ventilators should be used.

At the heart of the issue was the “bizarre” and “frankly baffling” phenomenon of Covid-19 patients with catastrophically low blood oxygen levels but few other ill effects.

“We’ve had patients with oxygen measures of just 5 kilopascals [70-75 per cent of normal] who are talking to us normally and have no obvious air hunger [gasping for breath]”, said Dr Daniels. “Normally anyone with numbers like that would be ventilated but increasingly with Covid patients we are considering holding back.

“The question everyone is asking is, do we treat symptoms or do we treat the numbers? It’s a good question and one that I think doctors everywhere are now grappling with.”

The initial recommendations from doctors in China and Italy were to ventilate Covid patients early and aggressively, with the so-called “PEEP” pressure on the machines turned up high so their lungs did not contract when they exhaled.

“The initial message was treat as if you were treating for acute respiratory distress syndrome (ARDS) with a high PEEP,” said Dr Daniels “But now we are becoming braver. We are tolerating much lower blood oxygen levels and using lower pressures. We are learning as we go along.” The alternative to mechanical ventilation is oxygen treatment delivered via a mask or a nasal cannula or via a non-invasive high-flow device. This is the sort of treatment that Boris Johnson is said to have received in an intensive care unit at St Thomas’ Hospital in London.

Increasingly, doctors in the UK, US and Europe are holding back on mechanical ventilation for as long as possible.

“Increasingly we are making the decision to focus on symptoms rather than numbers, predicting the point of fatigue where the patient is struggling to breathe independently,” said Dr Daniels.

Doctors in Italy and Germany wrote to the American Journal of Respiratory and Critical Care Medicine last week making a similar point. They urged other doctors to be “patient” with Covid patients, arguing for “gentle ventilation” wherever possible.

Invasive ventilation is never a good option for any patient. It can result in muscle wastage around the lungs and makes secondary infections more likely. It also requires a cocktail of drugs which themselves can prove toxic and lead to organ failure. It is not

known why Covid-19 allows some patients to tolerate such low blood oxygen readings without air hunger or obvious confusion. One clue may be that patients are still able to exhale carbon dioxide – a toxin – even if they are having difficulty absorbing oxygen.

“The patients in front of me are unlike any I’ve ever seen,” one American doctor told the specialist health publication STAT this week. “They looked a lot more like they had altitude sickness than pneumonia.”

Dr Daniels agreed that there were similarities with altitude sickness, itself a potentially fatal condition. “We’ve seen a lot of headache and dizziness,” he noted.

While doctors are not using mechanical ventilation as aggressively now, the machines remain a last resort for many Covid patients. Survival rates are not as good as for those with other forms of viral pneumonia but ventilators are nevertheless still saving many lives.

Intensive care units are also much more than just a ventilator. “It’s about having highly skilled staff to care for the patients and a whole plethora of ancillary equipment and medications beyond the ventilator itself,” said Dr Daniels.

‘The patients in front of me are unlike any I’ve ever seen. They looked a lot more like they had altitude sickness than pneumonia’