Basic Lab Data Flashcards
________ is the probability that a test will be negative in the absence of a disease.
Specificity
________ is the probability that the test will be positive in the presence of a disease.
Sensitivity
What is the Acid - Base balance conversion between HCO3 and CO2?
H + HCO3 H2CO3 H20 + CO2
What are the 2 main organs that help regulate acid - base imbalances?
Lungs - regulating the amount of CO2 present
Kidneys - regulate the amount of HCO3 excreted
Describe Uncompensated respiratory acidosis & alkalosis?
Acidosis: (Hypoventilation)
Decrease in pH
Increase in PaCO2
No Change in HCO3
Alkalosis: (Hyperventilation)
Increase in pH
Decrease in PaCO2
No Change in HCO3
Inverse Relationship
Describe Uncompensated metabolic acidosis & alkalosis?
Acidosis:
Decrease in pH
No Change in PaCO2
Decrease in HCO3
Alkalosis:
Increase in pH
No Change in PaCO2
Increase in HCO3
Similar Relationship
Describe the Anion Gap?
The Anion Gap is the measure of Cations + (Na and K) in relation to number of Anions - (Cl and HCO3), in the extra cellular space. (In relation to metabolic acidosis)
Anion Gap = (Na + K) - (Cl + HCO3)
(Law of Conservation of Change)
What is the Normal Range of the Anion Gap?
8 - 16 mEq/L
What is the Normal Range of pH?
7.35 - 7.45
What is the Normal Range of Partial Pressure of Carbon Dioxide (PaCO2)?
35 - 45 mmHg
What is the Normal Range of Serum Bicarbonate (HCO3)?
22-26 mEq/L
What is Base Excess? and what is the normal values?
Base Excess is the amount of base required to titrate the pH of one liter of blood to normal pH.
+3 to -3 mmol/L
What is the Normal Range of Partial Pressure of Oxygen (PaO2)?
80 - 100 mmHg
What is the Normal Range of Oxygen Saturation (SaO2)?
90 - 100%
What is the “Golden Rules” of ABG analysis?
1) For every 10 mmHg change in CO2, the pH will change 0.08 in the opposite direction
2) With every change in Bicarb of 10 mEq, the pH will change 0.15 in the same direction
What is the sequence of ABG Interpretation?
1) Check the pH
2) Check the PaCO2
3) Check the HCO3
4) Check the PaO2
5) Assess Anion Gap
Describe ABG Seesaw and ABG Elevator?
ABG Seesaw (Respiratory): - When pH goes one way and PaCO2 goes the opposite way
ABG Elevator (Metabolic): - When pH goes one way and HCO3 goes the same way