Acid/Base Disorders Flashcards
Acidemia definition.
pH <7.35
Alkalemia definition.
pH >7.45
Acidosis definition.
Condition tending to LOWER pH
Alkalosis definition.
Condition tending the RAISE pH
Respiratory Acidosis:
- Hypo/Hyperventilation
- Primary change
- Compensation
- Hypoventilation (insufficient elimination of CO2)
- CO2
- Altered renal handling of HCO3-
Respiratory Alkalosis:
- Hypo/Hyperventilation
- Primary change
- Compensation
- Hyperventilation (excess elimination of CO2)
- CO2
- Altered renal handling of HC03-
Metabolic Acidosis/Alkalosis:
- Cause
- Primary Change
- Compensation
- 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
Henderson-Hasselbalch Equation.
-normal individual
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])
Metabolic Acidosis:
- pH and HCO3 (same/opposite)
- HCO3 is usually what?
- Same Direction (both Decreased)
- HCO3 is usually 25 mEq/L
Respiratory Acidosis:
- pH and HCO3 (same/opposite)
- pCO2 is usually what?
Opposite Direction
- pH Decreased
- HCO3 increased
pCO2 is usually >44 mmHg
Metabolic Alkalosis:
- pH and HCO3 (same/opposite)
- bicarb is usually what?
- Same Direction (both Increased)
- HCO3 usually >25 mEq/L
Respiratory Alkalosis:
- pH and HCO3 (same/opposite)
- pCO2 is usually what?
Opposite direction
- pH Increased
- HCO3 Decreased
pCO2 is usually 40 mmHg
Determination if the compensation is appropriate:
-Metabolic Acidosis
For each 1.3 mEq fall in HCO3
-pCO2 decreases by 1.0 mmHg
Determination if the compensation is appropriate:
-Metabolic Alkalosis
For each 0.6 mEq rise in HCO3
-pCO2 increases by 1.0 mmHg
Determination if the compensation is appropriate:
-Acute Respiratory Acidosis/Alkalosis
For each 1 mmHg change in pCO2
-HCO3 changes by 0.1 in the same direction
Determination if the compensation is appropriate:
-Chronic Respiratory Acidosis/Alkalosis
For each 1 mmHg change in pCO2
-HCO3 changes by 0.4 in the same direction
Anion Gap calculation.
= [Na]-(Cl+HCO3)
Normal 10-14
What is often elevated in Nonanion Gap Acidosis?
Chloride (hyperchloremic metabolic acidosis)
When might you see a low anion gap?
- Hypoalbuminemia
- Paraproteinemia
Osmolal gap formula.
=Osm(measured)-(2[Na]+[Glucose]/18+[BUN]/2.8)
Normal <10
How are metabolic alkalosis categorized?
Chloride Responsiveness (Ucl<10) or Resistance (Ucl>10)
Metabolic Alkalosis:
-Chloride Responsive (Ucl<10). (6)
- Diuretics
- Vomiting
- NG tube suction
- Villous Adenoma
- Carbenicillin
- Contraction Alkalosis
Metabolic Alkalosis:
-Chloride Resistant (Ucl>10). (6)
- Hyperaldosteronism
- Cushing syndrome
- Exogenous Steroids
- Licorice (glycyrrhizin)
- Bartter syndrome
- Milk-Alkali syndrome
Respiratory Acidosis results from what?
Impairment of ventilation
Respiratory Alkalosis results from what?
Hypoxemia, in which compensatory hyperventilation leads to hypocapnea
Metabolic Acidosis with Increased Anion Gap (>12)
- Methanol
- Uremia
- Ketoacidosis
- Paraldehyde
- Lactic Acidosis
- Ethylene Glycol
- Salicylate
Metabolic Acidosis with Normal Anion gap (<12)
- Diarrhea
- Recovery phase DKA
- Ureterosigmoidostomy
- NH4Cl
- Carbonic Anhydrase Inhibitors
- Total parenteral nutrtion
- Renal Tubular Acidosis
Metabolic Acidosis with Increased Osmolal Gap.
- Methanol
- Propylene glycol
- Ethylene glycol
- Paraldehyde
- Ethanol (sometimes)
Metabolic Acidosis with normal Osmolal Gap.
- Isoproanol
- Glycerol
- Sorbitol
- Mannitol
- Acetone
- Ethanol (sometimes)
