From UPSC perspective, the following things are important :
Prelims level : Epithelial cell
Mains level : Paper 2-Oxygen requirement in covid patients
How Covid-19 leads to shortness of breath?
- Shortness of breath occurs because of the way Covid-19 affects the patient’s respiratory system.
- When a person inhales, the tiny air sacs in the lungs — alveoli — expand to capture this oxygen, which is then transferred to blood vessels and transported through the rest of the body.
- Respiratory epithelial cells line the respiratory tract.
- Their primary function is to protect the airway tract from pathogens and infections, and also facilitate gas exchange.
- And the SARS-CoV-2 coronavirus can infect these epithelial cells.
- To fight such infection, the body’s immune system releases cells that trigger inflammation.
- When this inflammatory immune response continues, it impedes the regular transfer of oxygen in the lungs.
- Simultaneously, fluids too build up.
- Both these factors combined make it difficult to breathe.
- Low levels of oxygen triggered by Covid-19 are inflammatory markers, which include elevated white blood cell counts and neutrophil counts.
Does a patient always show Covid symptoms when their oxygen levels drop?
- According to the FAQs on Covid-19 from AIIMS e-ICUS, sudden deaths have been reported at presentation to the emergency department, as well as in hospital.
- AIIMS has said that the reasons that have been proposed include a sudden cardiac event, preceding “silent hypoxia” that went unnoticed, or due to a thrombotic complication such as pulmonary thromboembolism.
- In silent hypoxia, patients have extremely low blood oxygen levels, yet do not show signs of breathlessness.