CBL Flashcards
What are the physiological principles of gas exchange at the alveolar interface?
Diffusion of oxygen from the air into capillaries. Diffusion of carbon dioxide from blood to alveoli. ;this occurs due to a concentration gradient. Oxygen moves from alveoli through alveoli epithelium and capillary endothelium to the blood
Outline the properties that maximise gas exchange
- Short diffusion distance
- Alveoli are highly vascular
- Very large surface area
- Highly ventilated
- Moist walls
What are the manifestations of Covid 19 in the airway and what effect does this have on gas exchange?
Continuous cough
Fever
Fatigue
Shortness of breath
- decreases gas exchange
What are the normal physiological responses to low blood pH, high CO2 and low O2 and where are the sensors that detect these levels?
Acidosis causes hyperventilation
Central chemoreceptors in medulla oblongata - PaCO2
Peripheral chemoreceptors in carotid and aortic arch - PaO2 and blood pH
Feedback to respiratory center
Stimulates inspiratory system DVG
Resp muscles stimulated
What is normal O2 saturation?
95-100%
How would you treat low oxygen saturation and what target would you set?
Oxygen supplement therapy
Oxygen saturation should be 88-92% until blood gases are available
Explain how the sensation of being breathless happens
Dypsnea
N
The man is not reporting, breathlessness or tachypnoea. What are the postulated reasons in COVID-19 that some of the normal responses are blunted?
The hospital is reporting no beds, would you admit him or send him home?
Describe the normal form of air in the upper and lower airways referring to macroscopic and microscopic anatomical features?
What are the changes to airflow pattern in asthma?
What are the underlying mechanisms of asthma? How does the structure of the bronchus provide the basis of the pathophysiology of asthma?
