Ventilators: not a COVID-19 cure-all
There are numerous reasons why someone would need mechanical ventilation, and in the heat of the COVID-19 pandemic, we’re hearing a lot about ventilators.
Many people think ventilation is a way to cure a serious respiratory problem, or that it’s a quick fix for when COVID-19 is making breathing difficult. Unfortunately, that's not the case.
In reality, mechanical ventilation is an intense undertaking that can have a big toll on the body, and isn’t something that can be used as a neat cure-all for any illness.
The basics of mechanical ventilation
The main purpose of a ventilator is to maintain a balance between the amount of oxygen and carbon dioxide in the body, as these levels can quickly become off-kilter when breathing is compromised.
Ventilators are usually used for patients who are in a critical state and in an intensive care unit (ICU), and they can’t protect their airways from food or liquids passing into them, or they are unable to breath by themselves.
There are two types of ventilation that are commonly used to help patients recover from serious respiratory illness.
For non-invasive ventilation, a tightly-fitting face mask is used to deliver extra air and oxygen to the patient, which may just cover the nose and mouth, or the entire head. The patient is not anaesthetised for this, and the mask delivers extra pressure when the patient breathes in themselves, meaning more oxygen is pushed into the airways.
In the case of novel coronavirus, non-invasive ventilation can pose contamination risks to staff and the surrounding environment, as the extra pressure used to deliver oxygen can escape from the mask and blow contaminated air out into the room.
For invasive ventilation, an endotracheal (ET) tube will be passed through the nose or mouth, past the vocal chords and into the trachea to protect the airways. As it’s an uncomfortable procedure, patients will be put under anaesthetic in order for the ET tube to be inserted into the trachea and will remain anaesthetised until they can come off ventilation.
Even if a patient isn’t suffering from respiratory illness, being sedated for any reason means ventilation will be needed regardless to help them breathe while they are unconscious.
There is a lot of talk about getting more ventilators into hospitals to deal with the huge surge in patients needing respiratory support because of COVID-19. Ventilators need to be connected to oxygen and air pipes in the hospital, much like taps and toilets need to be connected to water pipes in order to function. However, not every hospital is plumbed to house a ventilator, and as such, they can’t simply be put into every medical facility in every town to solve the shortage.
Along with the specialised ventilation set-up, not every nurse can operate a ventilator either, and those who can use them will have been trained for years in how to monitor patients on ventilation properly. As such, if there is a lack of these highly skilled, specialist teams, ventilation might not always be an option.
Does mechanical ventilation cure COVID-19?
No. Ventilation won’t cure any problem a patient is suffering from, but instead supports them until they recover or until any treatments they are undergoing do their job.
Some patients only need ventilation support for a matter of hours or days, but some patients will not come off ventilation at all. How long a person needs ventilation for depends on their overall health, how well their lungs were functioning before ventilation began, and how healthy their other vital organs are.
It’s important to note that not every patient is suitable for ventilation. If the patient is deemed unlikely to survive anaesthetic, they won’t be put on mechanical ventilation.
What problems can ventilation cause?
A big risk in ventilation is infection. Infection is always a risk when anything is inserted into the body, whether that is something as small as a needle, a catheter, or something as big as an ET tube. The risk of pneumonia also goes up when breathing tubes are inserted into the body.
There can also be damage done to the lungs while on ventilation, which can be caused by too much pressure being used by the ventilator to deliver the oxygen, too much oxygen being delivered to the lungs (oxygen toxicity), or weaknesses or damage to the lung itself resulting in pneumothorax, which is when air escapes from the lungs into the space between them and the chest wall.
Problems can also occur not as a result of ventilation, but as a result of being anaesthetised. Pressure sores, commonly called bedsores, can develop if a patient is anaesthetised for a long time, which are caused by long periods of inaction restricting blood flow to certain areas of the body that come into contact with the bed, such as the buttocks, back, and shoulder blades.
Intensive care units will use specialised mattresses called alternating pressure mattresses to lower the risk of complications like pressure sores occurring because of long periods of inaction. These mattresses create ‘waves’ that mean the body isn’t in contact with one part of the mattress for too long.
Long periods of anaesthesia can also significantly increase the risk of blood clots in the legs, which is a common worry for those on long haul flights, but can be combated by the use of intermittent pneumatic compression devices, which rhythmically compress the calves and encourage blood flow.
COVID-19 is characterised by widespread lung inflammation in its more serious cases, and if a patient is lying on their back for long periods of time under sedation, that inflammation can collect at the back and bottom halves of the lungs due to gravity. This area of the lung is crucial for transporting oxygen through the blood to the rest of the body, and if inflammation is impeding the lung’s ability to do that, the patient will need to be proned (moved to lie on their front) for around 12 hours at a time before being turned back over again.
There are big risks associated with proning. Tubes and lines can become disconnected while the patient is being turned onto their back and front, which can be life-threatening. As such, specialist proning teams will be used in order to safely move the patient and ensure catheters, lines, and tubes all stay connected throughout.
Coming off ventilation
When a person comes off ventilation, also called extubation, their chest muscles may ache when they begin to breathe on their own. This is because the muscles weaken considerably when mechanical ventilation replaces natural breathing.
Muscle weakness is a widespread issue if patients have been under sedation for long periods of time, and its estimated that every day spent under anaesthetic will require a week’s worth of recovery time in hospital.
There are also psychological effects of long-term sedation. As the anaesthetic is lightened, some patients can have flashbacks and stressful periods of recall and delirium as they begin to remember what has happened.
Ventilation is for the few, not the many
Around 85 percent of people who get the novel coronavirus will have mild symptoms and fully recover with no complications. It is just the remaining 15 percent that may need extra help from mechanical ventilation if their symptoms warrant it, and not all of these people will progress to this level of infection either. Ventilation is far from being an inevitability in COVID-19, but if you or someone you know does need ventilation, it's important to understand exactly what entails before, during, and after the illness.
Hope, E. What is it like to be in intensive care with coronavirus? (2020). https://www.youtube.com/watch?v=Lvr_uO7KWMo
IDSMed. How does a ventilator work? (2019). https://www.idsmed.com/news/how-does-a-ventilator-work_398.html
Iftikhar, N. The times a ventilator is needed. (2019). https://www.healthline.com/health/ventilator#how-it-works
NIH. Ventilator/ventilator support. ND. https://www.nhlbi.nih.gov/health-topics/ventilatorventilator-support
Images: Pixabay: Orlobs, Unsplash: Robina Weermeijer.