B4.051 - Acid Base Balance and Regulation of Ventilation

Question 1

Answer 1

5 and 5

Tidal x resp rate

Question 2

if minute ventilation does not change does that mean arterial blood gas would remain the same

Answer 2

no! rate of ventilation is important too

Question 3

equation for alveolar ventilation

Answer 3

(tidal volume - dead space) x respiratory rate

Question 4

Answer 4

Dead space is about 1/3 of normal tidal volume, so 150 ml is a reasonable estimate.

Although minute ventilation remained the same in the two periods, alveolar ventilation decreased when the person reduced tidal volume and increased respiratory rate.

Question 5

initial period TV = 500 RR = 10

final period TV = 250 RR = 20

Answer 5

Question 6

Answer 6

ventilation will increase

Question 7

what mechanism explains hyperventilation at high altitude

Answer 7

increased firing of peripheral due to low O2

decreased firing of central due to low CO2 from hyperventilation

Question 8

if ventilation is doubled what will PACO2 be and PaCO2

Answer 8

PCO2 is halved, PaCO2 can be found using alveolar gas equation

Question 9

which point demonstrates first day at high altitude

Answer 9

4

Question 10

what is HAPE

Answer 10

high altitude pulmonary edema

constriction of pulmonary arteries due to low O2 causes edema bc the downstream capillaries will cause increased hydrostatic pressure