ABG Classification

Question 1

Causes for
Respiratory Alkalemia
(3rd HORNS)

Answer 1

3rd Trimester of pregnancy
Hypoxemia
O2-too much mech.ventilation
Restrictive lung disorders
Neurologic-meningitis,aspirin,pain
Shock/decreased cardiac output

Question 2

Causes for
Metabolic Alkalemia
(H-HALLS)

Answer 2

Hyperaldosteronism-antacids,licorice
Hypokalemia
Accumulation of base in blood or
Loss of fixed acids
Loss of gastric fluid-diarrhea
Steroid use-prednisone

Question 3

Causes for
Metabolic Acidemia
(Anion Gap)

Answer 3

Normal AG - ACCRUED
Increased AG - MULEPAK
Decreased AG - loss of normal base

Question 4

What does MULEPAK stand for?

Answer 4

M Methanol (wood alcohols)
U Uremia (renal failure)
L Lactic acidemia 
E Ethylene glycol
P Paraldehyde toxicity
A Aspirin
K Keytones

Question 5

What does ACCRUED stand for?

Answer 5

A Acid infusion
C Compensation 4 resp. alkalemia
C Carbonic anhydrase inhibitors
R Renal tubular acidemia
U Urinary diversion
E Early renal disease
D Diarrhea

Question 6

Causes for
Respiratory Acidemia
(C DENNEM)

Answer 6

C COPD
D Drugs-barbits.,narcosis,sedatives
E Exhaustion-status asthmaticus
N Neuromuscular-GBS,MG,ALS
Neurologic Disorders-CSApnea,trauma
E Extreme V/Q mismatch 
M Metabolism-shivering,burns,TPN

Question 7

What is the one to one rule?

What is it used for?

Answer 7

For every 1mEq/L drop in HCO3 from normal(24mEq/L); PaCO2 should drop 1.1mmHg from normal (40mmHg)
Expected PaCO2
= 40-1.1(24-HCO3)
Used to calculate if the respiratory system is compensating for a metabolic acidemia.
If measured PaCO2 is higher than expected PaCO2, that a respiratory acidemia is also present

Question 8

What is an Anion Gap?

How is it calculated?

Answer 8

AG=Na-(Cl+HCO3)
Normal range is 9-14
(CBRC normal)

AG=(Na+K)-(Cl+HCO3)
Normal range is 15-20