What is severe COVID-19 and how is it treated?

Coronavirus disease-19 (COVID-19) is caused by the SARS-CoV-2 virus. The infection is transmitted through respiratory droplets and close contact. The main organs affected by COVID-19 are the lungs, heart, kidneys, genitals and liver.

Severe cases of COVID-19 include shortness of breath and have a relatively high death rate. Even healthy people can suffer from severe COVID-19. However, the risk of critical illness and death increases with age.

Serious illnesses are also more common in men than in women. The risk of serious illnesses is higher among certain ethnic groups such as black and Hispanic people in the United States. Additional risk factors for developing severe COVID-19 include cardiovascular disease, diabetes mellitus, immunosuppression, and obesity.

What is Severe COVID-19?

The most common first symptoms of COVID-19 are fever, cough, fatigue, headache, muscle pain, and diarrhea. Statistically, 5% of symptomatic patients are seriously ill while 14% have serious illness. There are wide variations in the duration of symptoms and complications caused by COVID-19. Generally, serious illness begins a week after the onset of symptoms.

Dyspnea (difficulty breathing) is the most common symptom of severe COVID-19 and occurs in 40% of symptomatic patients. Specifically, severe COVID-19 is diagnosed if the patient experiences:

A breathing rate of at least 30 breaths per minute
A blood oxygen saturation of 93% or less
Oxygen index of 300 mmHg
Infiltrates more than 50% of the lung field on lung imaging tests

Dyspnea is usually accompanied by hypoxemia (low blood oxygen levels). Many patients with severe COVID-19 also have progressive respiratory failure, lymphopenia, thromboembolic complications, and central or peripheral nervous system disorders.

Severe COVID-19 can lead to acute heart, kidney and liver damage. Other complications include shock, irregular heartbeat, rhabdomyolysis (rapid breakdown of damaged skeletal muscle) and coagulopathy (impaired ability to form blood clots). The main cause of death in patients with COVID-19 is respiratory failure, which is why the main treatment is airway support.

How is Severe COVID-19 Treated?

COVID-19 can be diagnosed with:

The patient's medical history
Detection of SARS-CoV-2-RNA in respiratory secretions
Chest x-rays reveal bilateral consolidations

Once diagnosed, the first step in treating severe COVID-19 is hospitalization for careful monitoring. Patients are monitored in the intensive care unit by direct observation and pulse oximetry (a non-invasive test that measures oxygen saturation). Oxygen supplementation with a nasal cannula or venturi mask is important to keep hemoglobin oxygen saturation at 90-96%.

Procedures currently used in the treatment of COVID-19 include endotracheal intubation, extubation, bronchoscopy, airway suction, nebulisation of medication, use of high flow nasal cannulas, non-invasive ventilation, and manual ventilation with a bag mask device. Patients being treated for severe COVID-19 need adequate nutrition and care to prevent further injury.

As per current guidelines, clinicians must wear appropriate Personal Protective Equipment (PPE), including gloves, robes, N95 masks, and eye protection, for patients with COVID-19. If possible, patients should also wear surgical masks to limit the spread of infectious droplets.

Deciding when to have endotracheal intubation to a patient with severe COVID-19 is an important part of care. Endotracheal intubation is performed by a skilled operator to insert a flexible plastic tube into the patient's windpipe to maintain an open and safe airway. The windpipe (also known as the windpipe) is a large tube that allows air to pass through.

After intubation, patients require lung-protective ventilation with a plateau pressure of 30 cm of water and a tidal volume that depends on the size of the patient. When patients do not require intubation but are hypoxemic, a high flow nasal cannula can be used to improve oxygenation.

Medications, including sedatives and analgesics, are widely used to help prevent pain, distress, and shortness of breath in patients with severe COVID-19. Dexamethasone is a steroid that is currently considered the standard for the treatment of these patients. This drug reduces the death rate in this group of patients in need of oxygen, especially those receiving oxygen through mechanical ventilation. A large clinical study showed that dexamethasone reduced mortality by 17% in patients with COVID-19 who needed oxygen supplementation.

Antivirals

Although remdesivir has been approved by the Food and Drug Administration (FDA) for the treatment of Covid-19 in hospitalized patients, more data is needed to understand its role in treating severe COVID-19. Remdesivir appears to have an antiviral mechanism of action as it has been shown to reduce the time it takes patients to reach clinical recovery. The combined use of dexamethasone and remdesivir is used more clinically, although its utility requires more research from clinical trials. Other antiviral drugs, including lopinavir and ritonavir, are currently being tested against COVID-19.

Patients with COVID-19 cannot be discharged from the intensive care unit and taken to a department for treatment until certain criteria are met. These criteria include:

No fever for at least three days
Significant improvements in respiratory problems
Breast scans show reduced lesions
No life-threatening damage to important organs

To control the high risk of complications from severe COVID-19, it is important that all infection control guidelines are followed and that treatment goals are promptly set for each patient.

References:

Berlin, D., Gulick, R. and Martinez, F. (2020). Severe Covid-19. The New England Journal of Medicine, 383 (25), 2451-2460. Retrieved from: https://www.nejm.org/doi/full/10.1056/NEJMcp2009575?query=featured_home

Xie, P. et al. (2020). Severe Covid-19: A Review of Recent Advances Looking Forward. Frontiers in Public Health, 8, 189.Retrieved from: https://doi.org/10.3389/fpubh.2020.00189

Image by Miguel Á. Padriñán from Pixabay