Acid Base Disorders

Question 1

What is the bicarbonate buffer system?

Answer 1

Co2 + h2O –> h2c03–> h+ + hco3-

Question 2

What controls the hydrogen ion concentration?

Answer 2

Ratio of lungs (pco2) to kidneys (hco3-)

Question 3

Acidemia

Answer 3

Decrease in blood pH less that 7.36

Question 4

Acidosis

Answer 4

Process that tends to lower blood pH

Question 5

Alkalemia

Answer 5

Increase in blood pH greater than 7,44

Question 6

Respiratory acidosis

Answer 6

Increase in pCO2 (will increase H+)

Question 7

What is compensation?

Answer 7

Normal physiological response to pH disturbance- tries to offset.

Ie kidneys try to compensate for respiratory acidosis by retaining HCO3

Lungs fast
Kidneys slower

Question 8

What is compensation for respiratory acidosis?

Answer 8

Pco2 10: 3 hco3 CHRONIC

10:1 ACUTE

Question 9

Compensation rules for respiratory alkalosis?

Answer 9

Pco2 10: 4 hco3 CHRONIC

10:2 ACUTE

Question 10

What is metabolic acidosis?

Answer 10

A decrease in bicarbonate (hco3)

Done by:

Acid gain ( so need to buffer) may be endogenous (ie lactic acid) or injested (ie too much aspirin)

Bicarbonate loss ( in GI or renal systems)

Diagnostic clues:
Low acid and low bicarb
Anion gap (in electrolytes)

Question 11

What is the anion gap?

Answer 11

Anion gap= sodium- (bicarbonate+ chloride)

A metabolic acid will be buffered, removing a bicarbonate from the system. This will increase the anion gap.

Question 12

What can increase the anion gap?

Answer 12

A mud pile

ASA
Methanol
Urea
Diabetic ketoacidosis
Paraldehyde
Isoniazid 
Lactate
Ethylene glycol

Question 13

Compensation rules for metabolic acidosis?

Answer 13

Drop hco3 by 10: pco2 by 12

Question 14

Rules for compensation for metabolic alkalosis?

Answer 14

Increase hco3 by 10: pco2 by 7

Question 15

What causes metabolic alkalosis?

Answer 15

Vomiting

Diuretics

Question 16

What is the delta gap?

Answer 16

Comparison of change in anion gap to change in bicarbonate

=(AG-12): (24-hco3)

Shows you if you have other processes contributing to metabolic acidosis

Question 17

What is the format of the arterial blood gas?

Answer 17

PH/pco2/pO2/ HCO3

Question 18

What is an approach to ABGS?

Answer 18

1. Look at pH (acidosis? Normal? Alkalosis?)
2. CO2? HCO3? What is happening with each?
3. Use overall pH to help determine the primary process ( respiratory vs metabolic)