Flashcards in Acid-Base Deck (27)
What four steps should be taken to assess a patient with a pH disorder?
1. Determine acidosis or alkalosis
2. Determine anion gap
3. Determine osmol gap
4. Determine delta gap
5. Look at history and physical
What is normal pH?
What is the equation used to calculate anion gap?
[Na] - ([HCO3] + [Cl])
What anion gap level is abnormal?
AG > 15
What equation is used to calculate serum osmolarity?
[Na]x2 + [Glucose]/18 + [BUN]/2.8
What is a normal osmolar gap?
Osm gap = 10
How do you calculate the delta gap?
Add the osmolar gap to the measured bicarb. It should equal the amount of normal bicarb (24-26)
What does it mean if the delta gap is low?
Non-anion gap acidosis
What does it mean if there is an elevated delta gap?
What are the potential causes of elevated anion gap acidosis?
D: Diabetic/Alcoholic ketoacidosis
I: Iron or INH
L: Lactic acidemia
E: Ethylene glycol
S: Salicylate overdose
What are the most common causes of an elevated Osm gap with metabolic acidosis and increased anion gap?
Methanol, ethylene glycol, alcoholic ketoacidosis
What levels would you expect creatinine and BUN to be in uremia?
Anion gap rarely over 20
What are some causes of lactic acidosis?
Sepsis, CO or CN poisoning
How do you treat ethylene glycol poisoning?
medications, alcohol, dialysis
What are some causes of metabolic acidosis with a normal anion gap?
Renal tubular acidosis
What do you give to someone with chloride responsive metabolic alkalosis?
What are some causes of chloride responsive alkalosis?
Cl wasting diarrhea (most diarrhea causes acidosis)
What is chloride unresponsive metabolic alkalosis usually due to?
Inappropriately high aldosterone levels
What can cause chloride unresponsive metabolic alkalosis?
Hyperaldo including Barter's
What is the primary disturbance in respiratory acidosis?
Increased arterial CO2
What does acute compensation of respiratory acidosis look like?
Increase HCO3 by 1 mEq per increase of 10 mEq CO2
What does chronic compensation of respiratory acidosis look like?
Increase of 3 mEq HCO3 per increase of 10 mEq CO2
What are common causes of respiratory acidosis?
Lung - COPD (by far most common), Asthma, Pneumothorax, infection
CNS depression - sedatives, hypnotics, tumor
What is the primary disturbance during respiratory alkalosis?
What does acute compensation of respiratory alkalosis look like?
HCO3 falls 2 mEq per decrease of 10 mEq CO2
What does chronic compensation of respiratory alkalosis look like?
HCO3 falls by 4 mEq per fall of 10 mEq of CO2