arterial blood gases Flashcards
two functions of blood
transportation: O2 to the tissues, CO2 from the tissues
homeostasis: control pH
what is atmospheric air made of
78% nitrogen
21% oxygen
1% argon and misc
atomspheric pressure
760 mm Hg
O2 about 160 mmHg
FiO2
% of O2 in the atmosphere being breathed in
how does supplemental oxygen change FiO2
for every 1L/min FiO2 increases 3%
Normal PAlveoli and PArt for O2 when breathing RA
108mmHg; 100 mm Hg
what role does N2 play in the lungs
helps keep alveoli open
short cut for determining normal PaO2 at different FiO2
goes up 50mm Hg with each 10% increase
eg. 30%–150, 40%–200 etc
how are PaO2 and PaCO2 affected by age
PaO2 should be 100 mm Hg but goes down with age, PaCO2 does not change, always 35-45 mm Hg
predicted PaO2 equation
90-(age-60) for people over 60, otherwise should be 100 mm Hg
levels of hypoxemia
mild: 65mm Hg to age appropriate
moderate: 40-64 mmHg
severe: <40 mm Hg
what can cause hypozemia
decreased minute ventilation
decreased alveolar ventilation
pulmonary shunt (blood that goes through the heart and lungs but does not go through external respiration)
normal arterial blood pH
7.35-7.45
what works to restore pH
respiratory system: PaCO2 (acid)
kidneys: HCo3- (bicarbonate, base)
respiratory acidosis
when the PaCO2 is above 45, causes acidemia
