ABGs Flashcards
(44 cards)
Normal pH
7.35-7.45
normal Pao2
75-100
normal paCo2
35-45
normal hco3
22-28
normal sao2
94-100
normal arterial vol
15-22%
normal venous vol
11-16%
critical pH values
<7.25, >7.6
Critical PaCo2
<20, >60
critical HC03
<10, >40
Critical PaO2
<40
O2 sat critical
<75%
What should you perform prior to ABG?
allen’s test
PaCO2 is elevated in
respiratory acidosis
metabolic alkalosis
PaCO2 is decreased in
respiratory alkalosis
metabolic acidosis
Majority of the CO2 in the blood is
HCO3 - regulated by the kidneys
elevated in metabolic alkalosis, decreased in metabolic acidosis
indirect measure of O2 in arterial blood
PaO2
decreased in: oxygen diffusion issues, premature mixing of arterial/venous blood (CHD), overperfusion (Pickwickian syndrome)
% of hemoglobin saturated w/ oxygen
O2 saturation
if carbon monoxide poisoning –> put O2 on
amount of oxygen in the blood
O2 sat * Hgb * 1.34 * PO2 * .003
base excess/deficit calculated by
pH, PaCO2, Hct, measuring amount of buffering anions
negative = metabolic acidosis
positive = metabolic alkalosis or compenstaed resp acidosis
When to draw an ABG?
resp failure, acid-base disorders, monitoring critically ill patients, evaluation of organ function, guiding therapy decisions
interpret ABG
1) check pH
2) analyze paCO2
3) analyze HC03
4_ compensatory mechanisms
high PaCO2, low pH
respiratory acidosis from COPD, asthma, overdose
low PaCO2, high pH
respiratory alkalosis from hyperventilation, anxiety, pain