Phosgene exposure causes inflammation and pulmonary edema that is deleterious to
ID: 3513028 • Letter: P
Question
Phosgene exposure causes inflammation and pulmonary edema that is deleterious to the function of the lungs.
(a)What are the three physical factors that influence pulmonary ventilation?
(b) How would each of these factors be affected by inflammation and edema?
After phosgene exposure, pulmonary gas exchange would decrease through the respiratory membrane, and the partial pressure of oxygen would drop as O2 is being consumed by cellular metabolic activity and not replenished by the alveoli. If the solubility of oxygen in blood plasma remains constant as the PO2 level drops, less oxygen would dissolve in blood plasma or other body fluids. This is an example of which of the following physical laws associated with the behavior of gases?
a. This is an example of Boyle’s law.
b. This is an example of Henry’s law.
c. This is an example of Dalton’s law of partial pressures.
d. This is an example of the pressure-volume relationship law.
Explanation / Answer
(a) Factors affecting pulmonary ventilation :
1- Surface tension of Alveolar fluid : regulated by pulmonary surfactants
2- Compliance of the lung : magnitude of change in lung volume as a result of the change in pulmonary pressure
3- Airway resistance - resistance in the respiratory tract to flow
(B) Effect of inflammation and oedema :
1- Surfactants : prevent pulmonary oedema by reducing surface tension
2- Compliance : decrease in case of inflammation and oedema and graph shifts to right and downward
3- Airway resistance : increase in case of pulmonary oedema and inflammation .
It is stated that according to Henry's law :
Amount of gas dissolved is directly proportional to it's partial pressure in the gas phase keeping the solubility of gas constant .