The number of Covid-19 cases is rising exponentially every day and there is no well-defined drug yet to cure the disease. While the development of a drug and a vaccine are crucial, Covid-19 patients will still require supportive treatment to deal with detrimental effects of the disease on other organs and bodily functions. What does this mean and how is this carried out? Here is all you need to know.
What is supportive treatment?
Supportive treatment or symptomatic treatment is the close monitoring of symptoms – i.e. what you tell the doctor – and signs – i.e. what the doctor finds through physical examinations and tests – and provision of interventions to retard their progression.
How do patients recover from Covid-19?
Every infectious disease has its natural course, which depends on the disease-causing agent and the body’s immune response. A drug can help with either or both. With a specific drug, the disease course becomes predictable, shorter and easier to manage. Without it, it is relatively unpredictable and depends on a variety of factors.
Supportive treatment helps the body fight the virus and cushions the damage caused by it. The body’s response to the virus can sometimes be extreme and cause unintended damages to other organs.
A variety of tests and complex devices are required to monitor the progress of patients in intensive care units. The most basic requirement is the ICU monitor, which tracks the patient’s pulse, rate of breathing, oxygen level, and heart rhythm continuously. These devices can be monitored remotely with telemetry available at some centres. Patients also require different imaging like ultrasound or CT scans.
Support for the lungs
In cases of lung complication, different levels of support may be required, depending on various factors such as the severity of the disease or levels of blood oxygen.
This includes the nasal cannula, which supplies one litre to eight litres of oxygen per minute, and the venturi mask, which supplies nine to 12 litres of oxygen per minute. The high flow nasal cannula uses a machine to pump high-flow humidified oxygen through a nasal cannula and supplies up to 60 litres of oxygen per minute.
Non-invasive positive pressure ventilation is a process through which the patient wears a tight-fitting facial mask and air is pumped with positive pressure through ventilators. It has some limitations and can only be used in patients who are awake. While this method is not preferred for Covid-19 cases due to the risk of aerosol generation, it is not contraindicated either.
Invasive ventilation begins by inserting a tube into the patient’s windpipe through a process called intubation. Intubation for Covid-19 patients is a high-risk procedure as it creates a lot of aerosols. It requires the doctor to wear personal protective equipment and take additional measures to prevent exposure. The tube is then connected to a mechanical ventilator and the patient is sedated or paralysed. Ventilator settings are complex and are adjusted according to disease severity and patient’s variables.
Prone ventilation improves oxygenation and is a proven protocol for advanced acute respiratory distress syndrome or ARDS. This is now being tried for patients with Covid-19, with anecdotal reports of success. The patient is flipped over and connected back to the standard ventilator. It doesn’t require a new device but personnel have to be trained for proning. Patients are proned typically for less than 16 hours per day.
Extracorporeal membrane oxygenation or ECMO is an advanced machine which replaces the function of the lung entirely. The ECMO machine pumps blood from the patient’s body to an artificial lung or oxygenator, which adds oxygen to it and removes carbon dioxide.
In addition to these, certain drugs are given to decrease the inflammation and dilate the pulmonary vessels, as indicated by standard protocols. Drugs are also required to sedate and paralyse patients on ventilator.
Support for falling blood pressure
When blood pressure falls due to overwhelming infection, it’s called a septic shock and is managed with fluids, antibiotics, steroids and pressor drugs that raise the blood pressure. The pressor drugs are given through infusion pumps, which deliver the drugs at a specific rate.
Support for the heart
Drugs are used to manage abnormal heart rhythms. Sometimes, direct current shock with a defibrillator is used, if indicated. Heart or pump failure is also managed with drugs initially. If it doesn’t respond to drugs measures like ultrafiltration – using dialysis machines – is tried. Finally mechanical supports like ECMO or intraaortic balloon pump can be tried.
Support for bleeding and abnormal clotting
As many as 16 of 183 patients from a study in Wuhan developed a condition called Disseminated Intravascular Coagulation or DIC, wherein patients develop bleeding and clotting abnormalities and is often fatal. Patients are given blood products like fresh frozen plasma, fibrinogen, and platelets according to different protocols. Patients with Covid-19 are also given preventive blood thinners to prevent formation of blood clots in legs that can go to the lungs.
Support for the kidneys
Around 2% to 29% of Covid-19 patients have developed acute kidney injury. Kidney failure is managed with dialysis machines, which can include intermittent dialysis, which are used routinely, or continuous renal replacement therapy or CRRT, which are specialised machines for continuous dialysis according to indications. Resource limited settings might also use acute peritoneal dialysis.
The CRRT machine is usually kept on the bedside but by it can be kept outside the room to minimise exposure to personnel by using extra tubing.
Support for the liver
Liver injury varies with severity of illness and there is no specific therapy for it. Acute liver failure has not been reported yet with Covid-19.
Palliative care
Drugs for anxiety, opioids and equivalent drugs for acute pain, drugs for vomiting and nausea, drugs for constipation, drugs to manage delirium and psychiatric counselling.
Are these supportive measures specific to Covid-19?
No, these are standard supportive care that are used in various scenarios and should be available in all major hospitals.
Why all the ventilator talk?
Covid-19 primarily affects the lungs and there are reports of rapid progression which necessitate early use of intubation and mechanical ventilation. Patients stay on ventilators for an average of 10-12 days when affected with Covid-19. Ventilators are already a limited resource and this long stay further increases the scarcity.
There are varied reports regarding survival of Covid-19 patients on ventilators, indicating a 20% survival rate in China, 36% in the United Kingdom and up to 50% in the United States. These depend on variety of factors. Standard protocol has to be followed when available.
What are the supportive care facilities available in India?
We have a shortage of high-flow nasal oxygen devices and training in prone ventilation in most government centres is inadequate. All aerosol-generating procedures, such as intubation, should be typically done in negative pressure rooms, which is not available in most institutes in India.
ECMO is a scarce resource in India available only in some chosen government centres and corporate hospitals. ECMOs were used for former finance minister Arun Jaitley and former Tamil Nadu chief minister Jayalalithaa. But it’s very expensive and out of reach for the common man.
Though the use of ECMO in a pandemic setting is questionable, there are reports of success from China and the United States. CRRT machines and mechanical heart supports are also limited resources in India.
Dr Amith Viswanath’s Twitter handle is @avstmd.
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