Lecture 18: Acid-Base Disturbances Flashcards
What is the primary defect of respiratory acidosis?
Hypoventilation: more arterial Carbon dioxide
-lowers pH
What is the compensatory response to respiratory acidosis?
Increased renal bicarbonate reabsorption
What is the primary defect of respiratory alkalosis?
Hyperventilation: less arterial Carbon dioxide
-increases pH
What is the compensatory response to respiratory alkalosis?
Decreased renal bicarbonate reabsorption
What is the primary defect of metabolic acidosis?
Loss of bicarbonate
Gain of hydrogen
What is the compensatory response to metabolic acidosis?
Hyperventilation: less arterial carbon dioxide
What is the primary defect of metabolic alkalosis?
Gain of bicarbonate
Loss of hydrogen
What is the compensatory response to metabolic alkalosis?
Hypoventilation: more arterial carbon dioxide
How is serum anion gap calculated?
[Na+] - {[Cl-] - [HCO3-]}
What is the normal range for serum anion gap?
8-16
How is serum osmolal gaps calculated?
Serum osmolarity measured - [ 2 x ([Na+] + [K+]) + glucose/18 + BUN/2.8]
What is the normal range for an osmolal gap?
< 10 mOsm/kg
How is Δ gap calculated?
Δ gap = calculated anion gap - normal anion gap
Δ gap = calculated anion gap - 12
How Δ[HCO3-] calculated?
Δ[HCO3-] = [normal HCO3-] - Δ gap
If measured [HCO3-] is about the same as Δ[HCO3-] what does that mean?
Simple acid-base disorder
If measured [HCO3-] > Δ[HCO3-] what does that mean?
Metabolic alkalosis
HAGMA (high anion gap metabolic acidosis)
If measured [HCO3-] < Δ[HCO3-] what does that mean?
Non-gap metabolic acidosis
HAGMA (high anion gap metabolic acidosis)
What are causes of acute respiratory acidosis?
CANS
- CNS depression (e.g. from opioids)
- Airway obstruction
- Neuromuscular disorders
- severe pneumonia, embolism, edema
What are causes of chronic respiratory acidosis?
COPD
Anything chronic that leads to impaired ventilation
For every 10 mmHg increase in arterial carbon dioxide, bicarbonate increases by ___ in acute respiratory acidosis and by ___ in chronic respiratory acidosis.
For every 10 mmHg increase in arterial carbon dioxide, bicarbonate increases by 1 in acute respiratory acidosis and by 3.5 in chronic respiratory acidosis.
What are causes of respiratory alkalosis?
CHAMPS
- CNS disease
- Hypoxia
- Anxiety
- Mechanical ventilators
- Progesterone
- Salicylates/sepsis
For every 10 mmHg decrease in arterial carbon dioxide, bicarbonate increases by ___ in acute respiratory alkalosis and by ___ in chronic respiratory alkalosis.
For every 10 mmHg decrease in arterial carbon dioxide, bicarbonate increases by 2 in acute respiratory alkalosis and by 5 in chronic respiratory alkalosis.
What are causes of high anion gap metabolic acidosis (HAGMA)?
GOLDMARK
- Glycolysis
- Oxoproline
- L-lactate
- D-lactate
- Methanol
- Aspirin
- Renal failure
- Ketoacidosis
What are causes of non-anion gap metabolic acidosis?
HARDUPS
- Hyperalimentation
- Acetazolamide
- Renal Tubular acidosis
- Diarrhea
- Ureterosigmoid fistula
- Post hypocapnia
- Spironolactone
What are causes of metabolic alkalosis?
CLEVER PD
- Contraction
- Licorice
- Endocrinology issues
- Vomiting (losing HCl)
- Excess Alkali
- Refeeding alkalosis
- post-hyercapnia
- Diuretics
