/ 26 June 2020

Observatory’s starring role in pandemic

Graphic Oxygen2 Twitter
(John McCann/M&G)

Being ventilated for life-threatening Covid-19 is a thoroughly nasty business. So the production of non-invasive ventilation devices in South Africa is a rare piece of good news in the pandemic.

Next month will see the first batch of non-invasive ventilators arrive in our hospitals, with a roll out of 20 000 in the pipeline. And, based on its stellar experience in developing complex systems for the MeerKAT radio telescope — a precursor to the Square Kilometre Array — the South African Radio Astronomy Observatory is managing the National Ventilator Project on behalf of the Solidarity Fund.

More than half of the 10 000 South Africans admitted to hospital with the infection have been discharged. 

For the critically ill, the standard medical response is tracheal intubation — the insertion of a flexible plastic tube via the mouth into the airway to move air in and out of the lungs.

But more and more experts are saying that this should be a last resort, both because it is traumatic and risky, and because the country does not have enough ventilators or specialised staff to administer them. 

The health department, therefore, is backing the move to roll out the 20 000 locally made Continuous Positive Airway Pressure (CPAP) and High-Flow Nasal Oxygen (HFNO) devices from July.

The CPAP is a mask or hood that provides the patient with a very small “overpressure” of air to ensure that the air sacs in the lungs remain inflated and promote the efficient transfer of oxygen to the blood. The hood or mask also prevents the virus-laden air exhaled by the patient from infecting hospital staff and other patients. 

The HFNO provides the required slight overpressure and raised oxygen concentration, but the air is supplied to the patient via a high-flow cannula inserted into the nostrils. The use of the non-invasive ventilators will now be ramped up to be the first port of call when Covid-19 victims are battling to breathe.

They are already in use in some hospitals and, according to Premier of the Western Cape, Alan Winde, doctors at Tygerberg Hospital have notched up some promising results. Of the six Covid-19 patients initially placed on ventilators at the hospital, all died. High-flow nasal oxygen was administered to seven other patients rather than putting them on ventilators — six came through. Since then, 114 patients have been admitted to Tygerberg for critical care, of which 70% met the criteria for the use of high-flow nasal oxygen. Of these, a further 70% have recovered. 

“This therapy will become a critical part of our healthcare response, creating an alternative for ventilation. Under the correct supervision, we believe it can also be administered in general wards, which will minimise the need for critical care beds,” said Winde.

Dr Angelique Coetzee, the head of the South African Medical Association, said the therapy could be a game-changer: “Ventilators can be quite tricky, and you need to ventilate the right person and have the right person to administer the procedure. There is a much bigger emphasis on having enough oxygen in the ordinary wards and ICU [intensive care unit]. We need to give patients a real fighting chance before we place them on ventilators.”

She and other experts on the ministerial advisory committee made recommendations on the use of CPAP to Health Minister Zweli Mkhize. 

Khulu Phasiwe, the spokesperson for the observatory, said about 75% of patients requiring hospitalisation for Covid-19 treatment only need low-level oxygen therapy, provided by low-flow nasal cannulae, to overcome their mild respiratory distress. The remaining 25%, with more serious respiratory symptoms, need some form of ventilator support. Most are treatable using non-invasive ventilator therapy. As they are simpler and locally manufactured, the new machines are significantly cheaper than imported ventilators.

“We hope to sign contracts for 10 000 today [Wednesday] and then aim to build at least 10 000 more —subject to the appropriate approvals and funding. The Solidarity Fund will award the contracts,” Phasiwe said.

Another member of the committee advising Mkhize, Dr Lance Lasersohn, explained that the first step with a Covid-19 patient is to give normal oxygen through a standard nasal cannula. Step two might be a mask with a higher oxygen concentration. 

“If that fails we can do something called ‘proning’ which essentially involves laying you on your tummy to get more oxygen into your lungs,” Lasersohn said.

The aim is to ensure that ventilation, a painful, invasive and technical procedure, is the last option.

“You need to insert special drips, and a catheter and a feeding tube in the nose or mouth to the stomach,” he said. “All of these foreign objects we put into your body introduce new ways for infection and complications, such as ventilator-associated pneumonia, to take hold.”

Retief Lourens, a critical care technologist who specialises in trauma and ICU treatment explained that intubation is a complex process in which the patient is sedated.

Once it has been established that the tube is correctly placed, the technologist or doctor will listen to the lungs to ensure that they are getting enough oxygen.

“Getting the settings right is quite a complicated process. Once the tube is in, you have to do an X-ray to see that it is in the correct place. The ventilator assists the steroids to work for you in stabilising the patient. 

“Ventilators are not a cure; they buy us time. Our focus should be on what happens before the ventilator stage. We need to take care of patients well enough so that they don’t need to go on ventilators,” said Lourens.

Clinical trial of coronavirus vaccine kicks off

The first clinical trials of a Covid-19 vaccine in Africa began in South Africa this week.

The vaccine, called ChAdOx1 nCoV-19 is already being evaluated in a clinical trial involving 4 000 participants in the United Kingdom. Other countries conducting similar and related trials include Brazil and the United States, which is planning to enroll up to 30 000 participants.

The vaccine has passed a number of rigorous reviews including the approval of the South African Health Products Regulatory Authority, the Human Research Ethics Committee of the University of the Witwatersrand, and the department of agriculture, forestry and fisheries, which approved the import of the “investigational” vaccine for use in the trial.

By vaccinating volunteers, scientists hope to make the human body recognise and develop antibodies. 

The trial is led by Shabir Madhi, professor of vaccinology at Wits and director of the South Africa Medical Research Council’s vaccines and infectious diseases analytics research unit.

Madhi said participants were screened last week and the trial will be conducted in a number of areas across the country.