ABGs

Question 1

what is an ABG?

Answer 1

a key physiological assessment tool used to evaluate acid-base balance, alveolar ventilation (PaCO2), and oxygenation status (PaO2)

Question 2

clinical relevance of acid-base balance

Answer 2

identifies life-threatening metabolic or respiratory disturbances that affect exercise tolerance, fatigue, and treatment

Question 3

clinical significance of alveolar ventilation

Answer 3

indicates how effectively the patient is moving air in and out of the lungs

Question 4

clinical significance of oxygenation status

Answer 4

shows whether tissues are receiving enough oxygen to support activity and healing

Question 5

ABGs vs pulse oximetry

Answer 5

ABGs give a precise and direct measurement of oxygen level, while pulse oximetry gives an indirect estimate that can be inaccurate under many conditions

Question 6

signs of acidosis

Answer 6

fatigue, nausea, headache, drowsiness, and confusion

Question 7

signs of alkalosis

Answer 7

confusion, disorientation, tremor, tingling/numbness, muscle weakness, or coma

Question 8

are ABGs done in acute or chronic settings?

Answer 8

acute

Question 9

clinical uses of ABGs

Answer 9

assess gas exchange function of the lungs, diagnosis of respiratory failure, diagnosis of acid-base disorders, and to determine eligibility for long term O2 use

Question 10

downsides of ABGs

Answer 10

requires arterial puncture and an invasive procedure

Question 11

problem list relevant to ABGs

Answer 11

impaired gas exchange and reduced alveolar ventilation

Question 12

what does an ABG measure in the blood?

Answer 12

O2, CO2, and pH in arterial blood

Question 13

in hyperventilation do you have low or high CO2 values?

Answer 13

low

Question 14

what value indicates hypoxemia?

Answer 14

< 80 mmHhg

Question 15

what value indicates hyperoxemia?

Answer 15

> 100 mm Hg

Question 16

what regulates CO2 levels?

Answer 16

the lungs

Question 17

what regulates HCO3 values?

Answer 17

metabolic system/kidneys

Question 18

what does the Henderson-Hasselbalch equation explain?

Answer 18

how CO2/HCO3 changes affect pH

Question 19

what variable changes with respiratory acidosis?

Answer 19

increased CO2

Question 20

what variable changes with respiratory alkalosis?

Answer 20

decreased CO2

Question 21

what variable changes with metabolic acidosis?

Answer 21

decreased HCO3

Question 22

what variable changes with metabolic alkalosis?

Answer 22

increased HCO3

Question 23

6 steps to analyzing ABGs

Answer 23

1. look at pH (acid, base, or normal) 2. look at PaCO2 3. look at HCO3 4. match CO2 or HCO3 to the pH to identify the primary disorder 5. assess compensation 6. assess oxygenation

Question 24

what type of compensation is a pH outside of normal values?

Answer 24

acute/uncompensated

Question 25

what type of compensation is a pH improving towards normal?

Answer 25

partially compensated

Question 26

what type of compensation is a pH normal but PaCO2 or HCO3 is still abnormal?

Answer 26

fully compensated

Question 27

uncompensated meaning

Answer 27

the pH is abnormal, only one parameter (either PaCO2 or HCO3) is abnormal, and the compensatory mechanism has not started or is insufficient

Question 28

partially compensated meaning

Answer 28

the pH is abnormal and both PaCO2 and HCO3 are abnormal, indicating that the body is attempting to correct the pH but has not fully done so yet

Question 29

fully compensated meaning

Answer 29

the pH is normal but both PaCO2 and HCO3 are abnormal, as compensation has successfully restored pH within normal range but the underlying balance is still present

Question 30

PT interventions for decreased alveolar ventilation

Answer 30

deep breathing exercises due to increased PaCO2

Question 31

PT interventions for hyperventilation

Answer 31

breathing control due to PaCO2

Question 32

pathologies affecting ABGs not due to hypoventilation

Answer 32

diffusion impairment, shunt, V/Q mismatch (these mean that decrease in O2 exceeds the increase in CO2)

Question 33

what indicates that hypoventilation is the primary cause of low O2 levels?

Answer 33

a rough 1:1 ratio between CO2 and O2