How Coronavirus Kills: Acute Respiratory Distress Syndrome (ARDS) & COVID 19 Treatment

Summary

This MedCram lecture explores how the coronavirus, like other viruses, causes death through Acute Respiratory Distress Syndrome (ARDS). It explains the anatomy of the lungs, the process of oxygen exchange, and how inflammation in ARDS leads to fluid buildup, impeding oxygenation. The speaker outlines critical medical strategies for improving survival in ARDS patients, such as low tidal volume ventilation, paralysis to sync patients with ventilators, and prone positioning. These approaches have significantly reduced mortality, emphasizing the importance of early intervention and proper medical care.

Takeaways

• 😀 ARDS (Acute Respiratory Distress Syndrome) is the main way coronavirus (and other viruses like influenza) can lead to death by preventing oxygen absorption into the bloodstream.
• 😀 The human lung can be compared to a tree, with airways branching down to tiny alveoli, where oxygen exchange occurs. In ARDS, inflammation fills these alveoli with fluid, impairing oxygenation.
• 😀 Inflammation caused by viral infections like coronavirus leads to fluid leakage into the lung tissue, disrupting the oxygen exchange process and causing hypoxia.
• 😀 ARDS can lead to severe hypoxia, and when a patient's blood oxygen levels drop too low, they may need to be placed on a ventilator for breathing support.
• 😀 Ventilators help patients breathe, but improperly managed ventilation can worsen ARDS by causing further damage to the alveoli, increasing inflammation, and making the condition worse.
• 😀 The 'low tidal volume strategy' involves using smaller volumes of air on the ventilator to prevent further lung injury, and has been shown to reduce mortality rates in ARDS patients.
• 😀 Paralysis and sedation are often used to help patients breathe in sync with the ventilator, preventing them from fighting the machine and reducing complications like blood clots or pressure drops.
• 😀 Prone positioning (lying patients on their stomachs) improves lung function in ARDS patients and has been shown to decrease mortality rates significantly when done for 17-18 hours a day.
• 😀 Early intervention and proper care, including timely ventilator use and low tidal volume ventilation, are key to improving survival rates for ARDS patients, especially during viral outbreaks like COVID-19.
• 😀 Research over the past two decades has led to significant improvements in ARDS treatment, with strategies like low tidal volume, paralysis, and prone positioning all contributing to better outcomes.
• 😀 Understanding the medical background of ARDS and how treatment strategies work is essential for increasing survival chances and reducing the fear around conditions like COVID-19.

Q & A

How does the coronavirus kill people?

The coronavirus can lead to death through a condition known as Acute Respiratory Distress Syndrome (ARDS), which causes widespread inflammation in the lungs, fluid accumulation in the alveoli, and impaired oxygen exchange, resulting in hypoxia and difficulty breathing.

What is ARDS and how does it contribute to death in coronavirus patients?

ARDS is a condition where the lungs become severely inflamed, leading to fluid leakage into the alveolar and interstitial spaces. This fluid accumulation hinders oxygen from diffusing into the bloodstream, causing hypoxia. The inability to oxygenate the blood sufficiently often requires mechanical ventilation and can lead to death if untreated.

What is the role of alveoli in the respiratory process?

Alveoli are small, grape-like structures in the lungs where oxygen from the air diffuses into the bloodstream. This process is crucial for oxygenating blood, which is then circulated throughout the body to supply oxygen to tissues and muscles.

Why do patients with ARDS need to be placed on ventilators?

Patients with ARDS often struggle to breathe due to fluid in the alveoli, making it difficult for oxygen to enter the bloodstream. Ventilators are used to provide mechanical assistance, ensuring the patient receives enough oxygen while the lungs recover.

What are the primary causes of inflammation in ARDS patients?

In ARDS, inflammation is typically caused by viral infections such as the coronavirus, which leads to a systemic inflammatory response in the lungs. This widespread inflammation causes the capillaries in the lungs to become leaky, allowing fluids and proteins to enter the alveolar spaces, impairing oxygen exchange.

How does the use of low tidal volume ventilation help ARDS patients?

Low tidal volume ventilation involves using smaller amounts of air during each breath, which reduces the risk of further lung injury. This method prevents the alveoli from repeatedly collapsing and reopening, which can exacerbate inflammation and worsen the patient's condition.

What are the risks of using high tidal volume ventilation in ARDS patients?

High tidal volume ventilation can cause shear stress in the lungs, leading to further damage and inflammation. This worsens the condition of ARDS patients because the lungs are already inflamed, and large volumes of air can make the injury worse, impeding the healing process.

Why might ARDS patients be sedated or paralyzed while on a ventilator?

Sedation or paralysis may be used to ensure that patients remain perfectly synchronized with the ventilator, preventing them from trying to breathe against it. This helps avoid additional complications like increased pressure on the lungs or ventilation inefficiencies.

How does prone positioning improve outcomes in ARDS patients?

Prone positioning (placing patients on their stomachs) helps improve oxygenation by redistributing blood flow and ventilation within the lungs. Studies show that patients who are positioned this way for 17-18 hours a day experience a significant reduction in mortality rates.

What are the key breakthroughs in the treatment of ARDS that have been identified in recent years?

Three key breakthroughs include: (1) the use of low tidal volume ventilation to reduce lung injury, (2) the use of paralysis to synchronize patients with the ventilator, and (3) prone positioning to improve oxygenation and reduce mortality.