There are currently no treatments against the virus itself or for the body’s harmful reaction to the virus. For now, the mainstay of treatment for patients with COVID-19 is ‘supportive care’. Rather than treating the underlying viral infection, supportive care aims to maintain the function of the body’s vital organs to keep the individual alive while the disease progresses and eventually resolves. More invasive treatments described below are not recommended to patients who are very frail or have severely debilitating health problems because they would not benefit from these treatments and would be discomforted by them.
Infected and damaged lungs are less effective at allowing oxygen to pass from the environment to the bloodstream. The main reason for being admitted to hospital with COVID-19 is to receive supplemental oxygen, to increase the amount of oxygen in the lungs and blood, which will be sufficient treatment before recovery in most cases. This can be administered in a number of ways, including into the nose using plastic tubing, or via a loose-fitting face mask.
Continuous Positive Airway Pressure (CPAP)
If breathing extra oxygen isn’t enough to improve the oxygen level in the blood, oxygen under pressure can be used to help the movement of gases in and out of the lungs. This is given via a tightly-fitting mask connected to a machine via plastic tubing. The patient remains awake, and doctors can control the pressure and amount of oxygen delivered by the machine. However, this treatment requires large quantities of oxygen, which may be limited in hospitals that are treating large numbers of COVID-19 patients. It may also create virus aerosols, putting healthcare workers at risk. Staff therefore require high levels of personal protective equipment (PPE) with suitable masks.
Invasive Mechanical Ventilation (IMV)
A small proportion of the most unwell patients with COVID-19 will be put on a ventilator. This treatment is called invasive mechanical ventilation (IMV), where a machine does the breathing for a patient. This requires the patient to be sedated and a breathing tube put into their windpipe (intubation). Doctors can control the pressure and the amount of oxygen delivered by the ventilator. Some ventilated patients benefit from being positioned on their front (proning), possibly because it opens up more of the lung and therefore allows for better exchange of gases between the air and bloodstream. Patients requiring simple oxygen therapy may also improve when adopting this position.
Ventilating a patient is not a quick or simple solution. It is continued for 10 days on average, and only a minority of people (33%) treated with IMV for COVID-19 have survived. Complications such as hospital-acquired bacterial infections of the chest, urine or bloodstream are common during treatment in ICU, which further increase the chance of the patient dying.
There are important resource considerations for treating large numbers of patients in ICUs. Treatment requires the availability of complex equipment such as ventilators. It also generally requires one highly-trained nurse per patient. Concerns about ICU capacity have led to many departments preemptively expanding.
Extracorporeal Membrane Oxygenation (ECMO)
In the UK, a very small number of critically unwell patients whose lungs are severely damaged and who were otherwise fit and healthy before COVID-19 are being treated with ECMO. This treatment requires a machine with two components – a pump that moves blood between the body and the machine, and a ‘membrane’ that acts as an artificial lung. It allows the body’s lungs to be rested which may give them a better chance to heal. It is only provided in a small number of specialist centres around the country.
Other organ support
In patients who are critically unwell, other organs such as the kidneys and the cardiovascular system (including the heart and blood vessels) may be affected. The kidneys perform the essential role of filtering the blood and removing waste products and fluid. In some cases, the impairment of kidney function is so severe that the patient requires a machine to perform the kidneys’ role of filtering blood; this is called renal replacement therapy or dialysis. A proportion of patients admitted to the Intensive Care Unit have very low blood pressure. If untreated, this could damage all organs by starving them of oxygen. Blood pressure can be maintained by infusing medications, such as noradrenaline.
Outstanding questions and areas for development
Because COVID-19 is a new disease, there is no clear evidence or consensus for the correct way to manage a critically unwell patient. Different approaches have been proposed based on early experience and knowledge of similar diseases caused by coronaviruses (e.g. SARS and MERS). Currently, around 50% of COVID-19 patients who are managed in an ICU environment survive, but this figure should improve as we gain a better understanding of the ways that COVID-19 causes illness.
With regard to supportive care, one important clinical question is the role that CPAP might play in avoiding the need for IMV. On one hand, some patients who would otherwise have been intubated have improved and recovered following a trial of CPAP. On the other hand, CPAP might mask further deterioration, possibly leading to patients being intubated too late. Our understanding of the role of CPAP may improve with time and experience, but formal clinical trials comparing outcomes in patients receiving different treatments are needed to provide clinicians with clear guidance.