Acid-Base Regulation Flashcards
What are the 3 steps for determining Acid base balance?
Question 1: What is the osis?
If pH < 7.35, then acidosis
If pH > 7.45, then alkalosis
Normal value of pH ~ 7.4
What is the cause of the osis?
Look at bicarbonate and see if it is elevated or decreased and compare to pH
Question 3 Was there compensation
A calculation must be perfromed to answer this quesiton
What are the “gold standard” values for arterial blood?
pH = 7.4
HCO3- = 24 mEq/L
PCO2 = 40 mmHg
How can you tell if there is mixed acidosis/alkalosis?
If HCO3 and PaCO2 go in opposite directions then is a mixed acidosis/alkalosis.
Follow the bicarbonate trail to determine if is alkalosis or acidosis
How do you calculate anion gap?
Na+ - (Cl- + bicarbonate)
Normal anion gap is between 12 +/- 2
What are substances that can cause an elevated anion gap metabolic acidosis?
MUDPILES
M: methanol
U: uremia (kidney failure)
D: diabetic ketoacidosis
P: paraldehyde
I: iron; isoniazid
L: lactic acidosis
E: ethylene glycol; ethanol ketoacidosis
S: salicylates; starvation ketoacidosis; sepsis
What are things that can cause a non-elevated anion gap metabolic acidosis?
HARDUP
H: hyperchloremia (parenteral nutrition)
A: acetazolamide
R: RTA
D: diarrhea
U: ureteral diversion
P: pancreatic fistula
Chart out a table to be able to distinguish and calculate metabolic acidosis from alkalosis and whether or not there is compensation.
Reproduce chart
Be able to ID the cause for each letter on the graph.
A: acute (uncompensated) respiratory acidosis
B: chronic (compensated) respiratory acidosis
C: metabolic alkalosis with respiratory compensation
D: metabolic acidosis with respiratory compensation
E: acute (uncompensated) respiratory alkalosis
F: chronic (compensated) respiratory alkalosis
What are some reasons for respiratory acidosis. (Give 4)
respiratory center depression (anesthetics, morphine)
pulmonary edema, cardiac arrest
airway obstruction
muscle relaxants
sleep apnea
chronic obstructive lung disease
neuromuscular defects (MS, muscular dystrophy
obesity hypoventilation syndrome
What are some causes of respiratory alkalosis? (List 4).
anxiety
fever
hypoxemia
pneumothorax (in some cases)
ventilation-perfusion inequality
hypotension
high altitude
What are some causes of metabolic alkalosis? (Name 4)
vomiting or gastric suctioning
loop and thiazide diuretics
Bartter, gitelman, and Liddle syndromes
Primary hyperaldosteronism
loss of bicarbonate-free fluid (contraction alkalosis)
shift of H+ ions as in hypokalemia
