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Infectious Diseases

Updated 15 October 2020

Cape Town hospitals prove oxygen therapy can improve Covid-19 patients' survival rate

A study conducted by Tygerberg and Groote Schuur hospitals shows that high-flow nasal oxygen treatment can help avoid the use of a ventilator in coronavirus cases.

  • A South African study proved the usefulness of high-flow nasal oxygen in severe Covid-19 cases.
  • Normally, patients in these cases would have had to be ventilated immediately, according to protocol.
  • Almost half of the patients on the treatment were discharged without the need for intubation.

One of the leading effects of Covid-19 is the drop in oxygen levels in the blood, which can severely worsen a patient's condition and lead to the need for a ventilator.

Unfortunately, since resources in the healthcare sector have been constrained during the pandemic, having ample ventilators on hand for Covid-19 patients can be difficult. Requiring a ventilator lowers one's survival rate considerably, and patients coming off the machines have a long recovery process ahead of them.

But a lesser-known treatment used at Tygerberg Hospital in Cape Town and other South African hospitals, has shown great promise in helping to better manage resources and increase Covid-19 patients' mortality rates.

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High-flow nasal oxygen

Heated and humidified oxygen is pumped directly into the lungs through the nose at 60 litres per minute, called high-flow nasal oxygen (HFNO) therapy. 

While it can't replace mechanical ventilation, it increases the recovery chances of Covid-19 patients with severe hypoxaemic respiratory failure (HRF). 

It also provides an additional treatment in resource-constrained situations, doesn't require the ICU to be administered - it can easily be set up in a general ward - and you don't need specially trained doctors and nurses to administer it.

Tears in the ICU

The Western Cape was the first province that become a hotspot in SA and when the first Covid-19 patients were hospitalised in Tygerberg's ICU, they lost many who received ventilation.

"The first seven patients all received ventilation, and unfortunately all of them died," recalls Dr Usha Lalla, who manages the Covid-19 ICU. 

"I remember the day so clearly - two of the patients died on the same day, and the ICU was in tears," adds Lalla, who is also an internal medicine specialist at Stellenbosch University's Faculty of Medicine and Health Sciences.

tDr Lalla Usha and Prof Coenie Koegelenberg

Dr Lalla Usha and Prof Coenie Koegelenberg (Image credit: Damien Schumann)

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Increased recovery rates

Lalla and her colleagues started discussing possible treatment options, and some hopeful reports around HFNO started coming out, although the data was limited. The Tygerberg doctors decided to test it in their wards.

"The first patient we treated with HFNO was up and chatting on her cellphone within five days - in stark contrast to patients who have to be ventilated for two to three weeks," says Lalla. 

"This gave us hope that we might not experience the carnage seen in other parts of the world."

They used the treatment on other Covid-19 patients and recovery rates increased. More hospitals in South Africa followed suit. It was also used at the temporary Hospital of Hope that was set up at the Cape Town International Convention Centre.

Published study

Alongside Groote Schuur Hospital and the University of Cape Town's Professor Greg Calligaro, the South African doctors published their success with HFNO in The Lancet's journal, EClinicalMedicine.

The data focused on almost 300 patients enrolled into the HFNO treatment programme. The average age of the patients was 52 years and more than half were men.

Out of that cohort, 47% of the patients were successfully weaned off oxygen therapy. On average, those who had success were on HFNO for six days. 

They also found their success rate increased when the ratio of oxygen-enriched air to respiratory was higher in six hours and used in conjunction with steroids.

In total 52% were discharged. In cases where HFNO treatment failed there was a 92% mortality rate.

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Other research

Before this South African study, there were only four small studies on HFNO treatment for Covid-19 patients, and none in a setting where resources were as limited. This is also the biggest study to date - not only in its relation to Covid-19 but also for pneumonia in general.

Some of the limitations in the study was whether they could not account for differences in the experience of the doctors and their decision when intubation was required. The trial also wasn't randomised. However, this would have been impractical due to the real-world situation of the pandemic and constrained resources.

A group effort

"Our study showed that HFNO can be successfully utilised to avoid the need for mechanical ventilation in half of all patients with severe disease," says Professor Coenie Koegelenberg, a Stellenbosch University pulmonologist who also works in Tygerberg Hospital's Covid-19 ICU.

"These patients fulfilled the criteria for acute respiratory distress syndrome, and if the recommended treatment protocol was followed, would all have had to be mechanically ventilated - yet we managed to support them successfully without it."

For Lalla, incorporating HFNO into the treatment strategy was a game-changer for them, despite the difficulties that came with switching to the treatment during the pandemic.

"Everybody just pulled together - health workers, hospital management, clinical and general engineers and volunteers. Everybody just did what needed to be done… and it was amazing."

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Image credit: Supplied