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How mechanical ventilation for Covid-19 has saved lives at Groote Schuur Hospital

How mechanical ventilation for Covid-19 has saved lives at Groote Schuur Hospital
The COVID Airway and Anaesthesia team at Groote Schuur Hospital during a simulation exercise. (Photo: Ross Hofmeyr)

While high-flow nasal oxygen has been one of the success stories of the Covid-19 pandemic, it is not always enough. Sometimes more invasive mechanical ventilation is required. Tiyese Jeranji spoke to Professor Ross Hofmeyr on what mechanical ventilation entails and the measures his team at Groote Schuur Hospital in Cape Town have employed to successfully manage these critical Covid-19 cases.

For Covid-19 patients with severe acute respiratory distress, mechanical ventilation is often the last resort to get oxygen into their lungs and increase chances for survival when all other non-invasive measures fail.

As the Western Cape pandemic peaked at the end of July, 95 Covid-19 patients in the province were on ventilators. By 6 September, this number had dropped to 47.

Nolusindiso Dayile, a paramedic hospitalised after she developed severe Covid-19 symptoms, was among those put on a ventilator to help her breathe. Dayile spent 44 days in Tygerberg Hospital, of which 23 days were in the ICU where her treatment included high-flow nasal oxygen before she was put on a ventilator. She was on the ventilator for nine days.

“All I remember is a few days when I went to the hospital because of shortness of breath. The doctors told me (afterwards) because my condition was getting worse by the day, I was intubated and after a couple of days I got better and came off the machine,” she says.

Dayile says she can now walk, sit up and even wash herself.

“I don’t remember a thing as I was asleep for the whole nine days. When I woke up my brain was not working properly and even now, it is very slow but I’m remembering things little by little. When I woke up, the doctors asked me the day and date. I couldn’t remember a thing. The only date I could remember was the 15th. I don’t know why, maybe because it is pay day,” she says.

“The doctors told me one of my fears (expressed) when I woke up was that I thought I didn’t have a home. I didn’t know where I was going to go after the hospital.” Dayile says she started remembering some things with the help of the psychiatrist. “Now I’m on special leave as I’m still recovering. I’m not strong, but getting better each day. It is still difficult to go up the stairs here at home,” she says, adding that she remembered her husband and children.

“When I got home, it was difficult to remember my neighbourhood, and spending time with my husband and asking questions is helping me remember stuff,” she says.

Dayile was discharged on 11 August.

At Groote Schuur Hospital, for patients such as Dayile, it is health workers like Professor Ross Hofmeyr and his Covid Airway and Anaesthesia team who will step in when they need mechanical ventilation.

According to Hofmeyr, they sedate patients to reduce anxiety, to keep them calm and in a state of unawareness. “We have seen in the ICU when people wake up, they don’t always remember what happened to them, so we have to account to the patients for that gap when they were on the ventilator. There is a disconnect for some patients. There are big gaps in time. It is normal for people who have been on a ventilator to have little recollection of situations,” he says.

Intubation vs high-flow nasal oxygen

Hofmeyr says patients such as Dayile, with serious Covid-19 symptoms, will first get high-flow nasal oxygen (HFNO) which is non-invasive oxygen therapy. Intubation (mechanical ventilation) is the last resort after high-flow nasal oxygen has failed to improve the patient’s condition. With HFNO, a rapid flow of warm, humidified oxygen is administered through the patient’s nostrils with the patient breathing for themselves. He explains this supports patients while they are still able to eat and care for themselves. For many patients, this has kept their oxygenation at a level that allowed them to recover from Covid-19 without requiring intubation and ventilation.

However, not everyone recovers with HFNO and it is then that Hofmeyr and his team work around the clock to save lives.

“As we moved into the surge of the pandemic, the survival rate for patients who needed mechanical ventilation was about one for every five or six patients.  There was an early realisation that with Covid-19, the greatest need is for oxygenation, and we began to use high-flow nasal oxygenation to save a lot of patients. Still, some of the sickest patients go on to require ventilation,” he says.

According to him the doctors who have been doing intubation to help their patients have seen many successes. “Despite the perception that ventilation can be harmful, I must say it was worthwhile, and we started to see results and lives being saved. We learnt to do everything to avoid ventilation. Ventilation was associated with poor results and a quarter will survive.  That is why we choose patients who had a greater chance of surviving and the ones we put on ventilation did very well,” says Hofmeyr.

How mechanical ventilation works

Hofmeyr explains intubation as the process of inserting a tube called an endotracheal tube (ETT) through the patient’s mouth into the airways. Through intubation, a patient can be put on a ventilator to help them breathe if they cannot maintain their oxygen levels on conventional or high-flow nasal oxygen therapies.

He says that intubation is not a comfortable process, but they have seen great results.

Hofmeyr says they put a tube through the patient’s mouth into the windpipe so that the ventilator takes over the breathing for the patient. “With many Covid-19 patients who need admission to hospital, there is severe lung disease. The lungs are not working any longer and can’t absorb enough oxygen. The respiratory muscles become tired, and the ventilator has to take over the breathing for these patients. They are in need of high-content oxygen but their lungs are not functioning as normal,” he says, adding that what makes Covid-19 different is the severity of hypoxia.

Hypoxia is when the whole body or certain organs don’t get enough oxygen, and for Covid-19 patients this can be particularly severe.

“The breathing mechanism is affected. Patients have viral pneumonia and oxygen is very low,” explains Hofmeyr. According to him, with normal air saturation, the oxygen level for a healthy person at a normal altitude should fluctuate between 96% and 100%, but for critically ill Covid-19 patients it is extremely difficult to maintain a normal oxygen level as it can drop below 75%.

“Some Covid-19 patients cope a lot longer with a very low oxygen saturation at around 80% for a week or two and they recover quite well. The body can adjust to lower saturation, as it does when we travel to high altitudes,” he says.

Hot one, two, three and the “bouncers”

In April, the South African Society of Anaesthesiologists published recommendations on airway management for Covid-19 patients.

Before intubation, doctors will prepare what they call a “hot” trolley. This is a steel trolley where they place all the instruments they will need for the procedure. This includes a bougie (a cylinder used to dilate the oesophagus), face masks, ETT, closed suction system (for drainage), oropharyngeal tubing (this is a device used to open a patient’s airway),  lubrication gel, HEPA filter (filtering harmful particles in the air), video laryngoscope  (a device used to identify vocal cords and pass tube between them), syringe, tape, scissors, yankaeur (a special suction tip which is used for oral suctioning) and tubing.

Working as a team, the three doctors who work closely with the patient are referred to as “Hot One”, “Hot Two” and “Hot Three”.

“When we were doing the training, everyone from all disciplines was trained to do everything. The hot ones ensure that they are fully protected and following all the procedures in theatre,” says Hofmeyr.

Also part of the team is the “not-hot” One and Two. “These two stand outside the operating room and ensure that we get what we need without going out. Not-hot one is just like the bouncer at a nightclub. They make sure that those in the operating room don’t go out as it will cause contamination. [They] also ensure that those outside don’t come in. Should we need anything, not-hot one will tell not-hot two to fetch whatever we need for the procedure,” he says.

Hofmeyr explains this is done to prevent infection.

Starting off, patients get a drug to sedate them. “Using a laryngoscope which has a video camera allows us to see what we are doing. We lift the tongue up. We ensure that the muscles around the airway are relaxed, then insert the ETT. There is a balloon cuff which is attached on the tip of the tube. Pressure on the balloon cuff is measured. If blown up too tight, it will affect the blood flow to the trachea and create another medical condition called tracheal stenosis (the narrowing of the windpipe),” he says.

Hofmeyr says that patients can be on a ventilator from two to six weeks.

“The machine has now taken over the breathing. Another tube is inserted [into] the bladder to take out urine,” he says, explaining that some of the greatest challenges in critical care involve the daily basic care of the patient.

“Because now the patient is not in control of their body, the nurses have to attentively look after all functions, including caring for the patients if they soil themselves. Patients are fed a special juice mixture, which is calculated according to the patient’s needs. It is trickle feeding which is worked out by a dietician and ensures that they get a lot of liquid, hence most of what is passed out is liquid.” Hofmeyr says this is done through another pipe, through the nostrils into the oesophagus.

After a couple of weeks, depending on how a patient is doing, the ETT may be exchanged for a tracheostomy. “A small cut is made in the front of the neck, and a shorter breathing tube called a tracheotomy tube is inserted. This tube is shorter and more comfortable, and patients can keep their mouth clean as they can now brush their teeth, and communication is much better,” he explains.

Hofmeyr says the aim is to get patients well and off the machines as quickly as possible to avoid complications. 

“Another issue with Covid-19 has been blood clots,” he says. “This can easily occur as the patient is lying on the bed with little movement so it is easy to get the blood clotting, especially in the deep veins of the legs. A further side effect is secondary pneumonia from being on a ventilator, and that is why we try by all means not to keep [a patient on] the ventilators for too long and we try to help them recover as quickly as they can.”

Being meticulous leads to success 

By the time of the interview (25 August), Hofmeyr and his team had intubated about 500 Covid-19 patients. He says he is proud of the fact that no one in his team has been infected. 

“Yes, we got PPE including goggles, visors and respirators, as intubation is a very risky aerosol-generating procedure. Respirators filter out even the minute particles of the virus that can be aerosolised during the procedure. We must say we have had no infection because we have been meticulous. Meticulous in using the correct PPE, but infection control was equally important. The cleaning of the equipment is also very important, and those are the things that really helped us. We ensure that we wash our hands and sanitise regularly,” he says.

“Donning is less of an issue, but doffing (taking off the PPE) is where the problems can occur. This has to be done effectively to ensure that you do not infect yourself. Straight after this, we go and shower before going to the tea room or seeing other patients. We ensure that before the procedure, you hand in your phone, keys and access cards. We don’t want a situation where your phone rings, then you answer it [and] put it back in your pocket. Then at lunchtime you’re sitting and scrolling on your Instagram and that phone might have the virus. Working in such a stressful environment it is easy to forget things, so we had buddy checks to ensure that everyone has proper PPE for any procedure,” he says. 

Replicating the successes with fewer resources?

Hofmeyr says what they do can easily be replicated elsewhere, including in rural areas, but more has to be done on infection control and the big challenge is education.

“Education is critical and if I were to be in the rural areas, I would start with basic infection control and proper use of PPE.”

Hofmeyr says sanitising and regular washing of hands with soap is crucial, and so is appropriately donning and doffing. He stresses the importance of training the teams and understanding how to handle the PPE properly, because you can end up infecting yourself. “Good guidelines need to be followed, especially in the rural areas – how to oxygenate successfully, knowledge of when to transfer a patient to a special hospital – because if that is not properly done, special hospitals will be flooded by cases that don’t need to go there and that can strangle the system,” he says. DM/MC

 *This article was produced by Spotlight – health journalism in the public interest. Sign up for our newsletter.

 

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