Lecture 3 - Respiratory Pathophyiology II

Question 1

3 key characteristics of COPD?

Answer 1

chronic mucus hypersecretion, emphysema, small airway inflamm

Question 2

3 compartment model of lung?

Answer 2

dead space w ventilation but no perfusion, venous admixutre or shunt with perfusion but limited ventilation, and the ideal normal compartment

Question 3

Hypercapnic drive?

Answer 3

increased ventilation rate and alveolar ventilation, also sensitive to H+ in CSF from respiratory acidosis

Question 4

Hypoxic drive?

Answer 4

response only to severe hypoxia (80%)

Question 5

Dissociation curves and the drives?

Answer 5

normal compartment is on flat aspect of oxygen dissociation curve therefore hyperventilating will increase PAO2 with minimal effect on oxygen level; CO2 level and PACO2 drop significantly

Question 6

Chronic hypercapcia?

Answer 6

due to constant elevated PaCO2, chemreceptors become sensitive to higher CO2 values, meaning a patient is more dependent on hypoxic drive; elevated bicarbonate indicates this

Question 7

Differentiating venous admixture and R-L shunt?

Answer 7

giving 100% will cause major rise of PaO2 in venous admixture