Ventilation Flashcards
VD
anatomical dead space
all the space between the nose-mouth and the gas-exchanging surfaces of the alveoli
alveolar ventilation
VA - the amount of oxygen that reaches the alveoli to participate in gas exchange
Will there be a larger increase in alveolar ventilation if minute ventilation is increase by tidal volume or frequency?
tidal volume
causees of alveolar dead space
hydrostatic failure of alveolar perfusion
pulmonary embolus
ventilation of non-vascular air space
obstruction of pulmonary circulation by external forces
physiologic dead space
total volume of inhaled gas that does not participate in gas exchange
sum of anatomic and alveolar dead spaces
respiratory quotient (state normal)
VCO2/VO2
the ratio of inspired and expired O2 molecules
normally a value of 0.8
majro differences between alveolar air and ambient air
water vapor saturation of alveolar air at body temp
presence of significant amount of CO2 in alveolar air
alveolar gas equation
PAO2 = PIO2 - (PACO2/RQ)
normal PAO2 values
80-100 mmHg
normal PACO2 and clinical range
textbook normal - 40 mmHg
clinical range - 35-45 mmHg
describe the relationship between alveolar ventilation and PACO2
hyperbolic, exact shape dependso n level of metabolic carbon dioxide production
hyperventilation
greater alveolar ventilation than needed to maintain normal PCO2
hypoventilation
lower ventilation than necessary to maintain normal PCO2
hyperpnea
the ventilatory response for when metabolic rate increases and there is an increase in alveolar ventilation that is appropriate to maintain a constant level of arterial PCO2
hypopnea
the compensatory decrease in alveolar ventilation to maintain PaCO2 when metabolism decreases
Describe the relationship between alveolar ventilation and PAO2.
have to account for the oxygen in the inspired gas
alveolar PO2 hyperbolically increases, asymptotically approaching the inspired PO2
