In the midst of the Covid-19 pandemic, doctors at Tygerberg Hospital implemented a daring, lesser-known treatment that not only bypassed the imminent ventilator shortage caused by the large number of critically ill patients, but potentially saved thousands of lives while also providing a more patient-friendly experience.
In a research article published this week in The Lancet’s EClinicalMedicine, medical experts from Stellenbosch University (SU) and the University of Cape Town (UCT) described how they were able to successfully treat half of all their critically ill Covid-19 patients by using high-flow nasal oxygen (HFNO), and avoiding mechanical ventilation.
HFNO is a non-invasive oxygen therapy that channels oxygen into the lungs through nasal tubes at a high flow rate – up to 60 litres per minute. HFNO is considered to be ‘gentler’ on patients than mechanical ventilation and allows patients to eat, talk and engage with others in the ward. Ventilation, on the other hand, is an invasive treatment that requires a tube to be inserted into the patient’s airway. This can cause severe discomfort and necessitates sedation in some patients.
When the first Covid-19 patients with acute respiratory distress were admitted to Tygerberg Hospital’s intensive care unit (ICU) in March this year, doctors treated them according to the internationally recommended regimen of mechanical ventilation.
In line with international trends, there were high mortality rates among ventilated patients.
“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,” says Lalla, who is also an internal medicine specialist with SU’s Faculty of Medicine and Health Sciences.
At that time, a few anecdotal reports started emerging about the use of HFNO therapy in Covid-19 patients, but generally there was a reluctance to use this lesser-known treatment.
“I remember discussing it with colleagues, including Prof Mervin Mer from Wits University, and saying that a large proportion of the patients just need oxygen – why don’t we try it? The first patient we treated with HFNO was up and chatting on her cell phone 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 treated more patients with HFNO, and achieved much higher recovery rates with this new treatment than going straight to mechanical ventilation. News of the success of HFNO therapy quickly spread to other hospitals in the province and later, around the country, who also rapidly adopted it. This modality was also implemented at Cape Town’s Hospital of Hope where engineers had to adapt the infrastructure at short notice to accommodate this new therapy.
High flow nasal oxygen does not replace mechanical ventilation, which is still extensively used in the management of Covid-19 patients, but provides an extra ‘weapon’ in doctors’ arsenal in the fight against Covid-19.
“For a resource-constrained setting in the midst of a pandemic, this had a massive impact on the management of patients,” says Prof Coenie Koegelenberg, a SU pulmonologist who also works in Tygerberg Hospital’s Covid-19 ICU.
Unlike mechanical ventilation that has to be managed in the ICU, HFNO can be administered in the general ward – provided that the hospitals’ infrastructure provides for the higher flow of oxygen required. Furthermore, it can be safely managed by non-ICU trained doctors and nurses, saving on the country’s sparse healthcare resources.
The doctors from Stellenbosch University (Tygerberg Hospital) collaborated with Prof Greg Calligaro’s team at UCT (Groote Schuur Hospital) to combine data of approximately 300 Covid-19 patients who received HFNO therapy at these facilities. The resulting research article is by far of one the biggest studies to date on HFNO, not only in Covid-19 patients, but for any form of pneumonia.
“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 Koegelenberg. “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.”
“High flow made an enormous difference to our capacity to treat patients during this pandemic. But it was no easy feat changing tack from ventilation to HFNO in the middle of a pandemic,” comments Lalla. “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.”