Acid/Base Disorders

Question 1

Acidemia definition.

Answer 1

pH <7.35

Question 2

Alkalemia definition.

Answer 2

pH >7.45

Question 3

Acidosis definition.

Answer 3

Condition tending to LOWER pH

Question 4

Alkalosis definition.

Answer 4

Condition tending the RAISE pH

Question 5

Respiratory Acidosis:

• Hypo/Hyperventilation
• Primary change
• Compensation

Answer 5

• Hypoventilation (insufficient elimination of CO2)
• CO2
• Altered renal handling of HCO3-

Question 6

Respiratory Alkalosis:

• Hypo/Hyperventilation
• Primary change
• Compensation

Answer 6

• Hyperventilation (excess elimination of CO2)
• CO2
• Altered renal handling of HC03-

Question 7

Metabolic Acidosis/Alkalosis:

• Cause
• Primary Change
• Compensation

Answer 7

• Excessive intake of, excessive production of, or too little renal elimination of an acid or a base
• Bicarbonate (HCO3-)
• Alteration in pulmonary handling of CO2

Question 8

Henderson-Hasselbalch Equation.

-normal individual

Answer 8

pH=pKa+log(base/acid)

pH=6.1+log(bicarb/[0.03xPaCO2])

pH=7.4
pKa=6.1
Base(Bicarbonate;HCO3-)=24 mol/L
Acid(Carbonic Acid;H2CO3)=0.03xPaCO2
- 0.03x40mmHg= 1.2 mol/L

Thus:
pH=6.1+log(bicarb/[0.03xPaCO2])

Question 9

Metabolic Acidosis:

• pH and HCO3 (same/opposite)
• HCO3 is usually what?

Answer 9

• Same Direction (both Decreased)

- HCO3 is usually 25 mEq/L

Question 10

Respiratory Acidosis:

• pH and HCO3 (same/opposite)
• pCO2 is usually what?

Answer 10

Opposite Direction

• pH Decreased
• HCO3 increased

pCO2 is usually >44 mmHg

Question 11

Metabolic Alkalosis:

• pH and HCO3 (same/opposite)
• bicarb is usually what?

Answer 11

• Same Direction (both Increased)

- HCO3 usually >25 mEq/L

Question 12

Respiratory Alkalosis:

• pH and HCO3 (same/opposite)
• pCO2 is usually what?

Answer 12

Opposite direction

• pH Increased
• HCO3 Decreased

pCO2 is usually 40 mmHg

Question 13

Determination if the compensation is appropriate:

-Metabolic Acidosis

Answer 13

For each 1.3 mEq fall in HCO3

-pCO2 decreases by 1.0 mmHg

Question 14

Determination if the compensation is appropriate:

-Metabolic Alkalosis

Answer 14

For each 0.6 mEq rise in HCO3

-pCO2 increases by 1.0 mmHg

Question 15

Determination if the compensation is appropriate:

-Acute Respiratory Acidosis/Alkalosis

Answer 15

For each 1 mmHg change in pCO2

-HCO3 changes by 0.1 in the same direction

Question 16

Determination if the compensation is appropriate:

-Chronic Respiratory Acidosis/Alkalosis

Answer 16

For each 1 mmHg change in pCO2

-HCO3 changes by 0.4 in the same direction

Question 17

Anion Gap calculation.

Answer 17

= [Na]-(Cl+HCO3)

Normal 10-14

Question 18

What is often elevated in Nonanion Gap Acidosis?

Answer 18

Chloride (hyperchloremic metabolic acidosis)

Question 19

When might you see a low anion gap?

Answer 19

• Hypoalbuminemia

- Paraproteinemia

Question 20

Osmolal gap formula.

Answer 20

=Osm(measured)-(2[Na]+[Glucose]/18+[BUN]/2.8)

Normal <10

Question 21

How are metabolic alkalosis categorized?

Answer 21

Chloride Responsiveness (Ucl<10) or Resistance (Ucl>10)

Question 22

Metabolic Alkalosis:

-Chloride Responsive (Ucl<10). (6)

Answer 22

• Diuretics
• Vomiting
• NG tube suction
• Villous Adenoma
• Carbenicillin
• Contraction Alkalosis

Question 23

Metabolic Alkalosis:

-Chloride Resistant (Ucl>10). (6)

Answer 23

• Hyperaldosteronism
• Cushing syndrome
• Exogenous Steroids
• Licorice (glycyrrhizin)
• Bartter syndrome
• Milk-Alkali syndrome

Question 24

Respiratory Acidosis results from what?

Answer 24

Impairment of ventilation

Question 25

Respiratory Alkalosis results from what?

Answer 25

Hypoxemia, in which compensatory hyperventilation leads to hypocapnea

Question 26

Metabolic Acidosis with Increased Anion Gap (>12)

Answer 26

- Methanol - Uremia - Ketoacidosis - Paraldehyde - Lactic Acidosis - Ethylene Glycol - Salicylate

Question 27

Metabolic Acidosis with Normal Anion gap (<12)

Answer 27

- Diarrhea - Recovery phase DKA - Ureterosigmoidostomy - NH4Cl - Carbonic Anhydrase Inhibitors - Total parenteral nutrtion - Renal Tubular Acidosis

Question 28

Metabolic Acidosis with Increased Osmolal Gap.

Answer 28

- Methanol - Propylene glycol - Ethylene glycol - Paraldehyde - Ethanol (sometimes)

Question 29

Metabolic Acidosis with normal Osmolal Gap.

Answer 29

- Isoproanol - Glycerol - Sorbitol - Mannitol - Acetone - Ethanol (sometimes)