AcidBase Pathologies

Question 1

Normal pH range

Answer 1

7.35-7.45

Most common normal = 7.40

Question 2

Normal PCO2 range

Answer 2

35-45 mmHg

Most common normal = 40 mmHg

Question 3

Normal HCO3- range

Answer 3

22-28 mEq/L

Most common normal = 24

Question 4

Basic metabolic panel includes what?

Answer 4

Na+/K+/Cl-/HCO3-/BUN/Creatinine/Glucose

CO2 = HCO3-

Question 5

Arterial blood gas includes what?

Answer 5

pH

PaO2

PaCO2

HCO3-

SaO2

**PCO2 = H+/acid

Question 6

What are causes of respiratory acidosis?

Answer 6

Decreased central respiratory drive

• opiods
• sedative
• encephalopathy

Decreases neuromuscular/thoracic cage function

• polio
• Guillain-Barre
• myasthenia gravis
• obesity

Increased dead space

• COPD
• ARDS

Question 7

What are causes of respiratory alkalosis?

Answer 7

Anything that leads to hyperventilation

• anxiety
• panic disorders
• pain
• high altitudes
• pulmonary embolisms

Question 8

What are causes of metabolic alkalosis

Answer 8

Any loss of H+

• vomiting
• hyperaldosteronism
• overuse of loop diuretics w/ secondary hyperaldosteronism
• severe hypokalemia (causes increased intracellular H+ shift and increased renal H+ excretion)
• contraction alkalosis (loss of significant amounts of fluid high in Na+/Cl-, but low in HCO3-) (includes loop diuretics and CHF)

Question 9

Causes of metabolic acidosis

Answer 9

There are a lot and have to calculate the anion gap.

Causes are divided into 2 subcategories

1) involving an additional acidic substance in the blood
- if anion gap > 12

2) those not involving an additional substance in the blood
- if anion gap <12 or normal

Question 10

Anion gap

Answer 10

Determines the levels of non Na+/Cl-/HCO3- in the blood

Equation
Na+ - ([HCO3-] + [Cl-]) = anion gap

Normal = 12 (8-16)

on a BMP, CO2=HCO3-

Question 11

What are the 4 general types of anion gap metabolic acidosis?

Answer 11

1) lactic acidosis
2) ketoacidosis
3) toxins/drugs
4) severe kidney failure

subtypes of these 4 are “MUDPILES”
Methanol 
Uremia
Diabetic Ketoacidosis 
Propylene glycol 
Lactic Acidosis 
Ethylene glycol 
Salicylate

Question 12

Osmolality gap

Answer 12

Used to further differentiate anion gap metabolic acidosis causes

Question 13

Hyperchloremic metabolic acidosis

Answer 13

A non-anion gap metabolic acidosis where Cl- elevates to overtake normal HCO3- levels

Anion gap will show normal, but bicarbonate will be low and Cl- will be elevated

Question 14

Causes of non-anion cap metabolic acidosis

Answer 14

Loss of bicarbonate

• diarrhea
• proximal (type 2) renal tubular acidosis (causes decreases reabsorption of bicarbonate)
• chronic acetazolamide use

Reduced acid excretion

• Distal (type 1) renal tubular acidosis
• hypoaldosteronism
• overuse of spironolactone

Relative hypercholremia (drive HCO3 into cells which leads to acidosis in blood)