Acid-Base - Wall

Question 1

What are volatile acids and how are they excreted?

Answer 1

Carbonic acid

Lungs

Question 2

What are nonvolatile acids and how are they secreted?

Answer 2

Non-carbonic acids (ie phosphoric, sulfuric acid)

Excreted by kidney

Question 3

What is the equation for the bicarbonate buffer system?

Answer 3

CO2 + H20 <-> H2CO2 <-> H + HCO3

Question 4

What is the equation for the hydrogen ion concentration?

Answer 4

H = 24 * CO2 / HCO3

CO2 = 40

HCO3 = 24

Must convert pH to nEq/L (pH 7.4 = 40 nEq/L)

Question 5

What is the corresponding [H] for the given pHs: 7.1, 7.4, 7.7?

Answer 5

7. 1 - 80
8. 4 - 40
9. 7 - 20

Question 6

What is the defintion of a metabolic disorder?

Answer 6

Process that directly alters bicarbonate concentration

Question 7

What is the definition of a respiratory disorder?

Answer 7

Process that directly alters CO2

Question 8

What is the major extracellular buffer?

Answer 8

Bicarbonate

Question 9

What are the major buffers in ECFV, urine, and ICF?

Answer 9

ECFV - bicarbonate

Urine - Phosphate and ammonia

ICF - Protein

Question 10

What are the secondary mechanisms or metabolic and respiratory disorders and how quickly do they act?

Answer 10

Respiratory system compenates for metabolic disorders (rapid, minutes)

Bicarbonate concentration compensates for respiratory disorters (1-2 days)

Question 11

What are the changes in pH, HCO3, and pCO2 in metabolic acidosis?

Answer 11

pH - decreases

HCO3 - decreases (PRIMARY)

pCO2 - decreases (COMPENSATORY)

Question 12

What are the changes in pH, HCO3, and pCO2 in metabolic alkalosis?

Answer 12

pH - increases

HCO3 - increases (PRIMARY)

pCO2 - increases (COMPENSATORY)

Question 13

What are the changes in pH, HCO3, and pCO2 in respiratory acidosis?

Answer 13

pH - decreases

HCO3 - increases (COMPENSATORY)

pCO2 - increases (PRIMARY)

Question 14

What are the changes in pH, HCO3, and pCO2 in respiratory alkalosis?

Answer 14

pH - increases

HCO3 - decreases (COMPENSATORY)

pCO2 - decreases (PRIMARY)

Question 15

What causes metabolic acidosis?

Answer 15

Decreased renal acid excretion (RTA I, RTA 4)

Direct bicarbonate losses (GI or urine)

Increased acid generation (Lacticacidosis, ketoacidosis aspirin, animal protein)

Question 16

What causes respiratory acidosis?

Answer 16

Hypercapnia (too much carbon dioxide)

Decrease breathing (ie obstructive pulmonary disease)

Question 17

What is the compensatory mechanism in response to respiratory acidosis?

Answer 17

Buffering raises plasma bicarbonate

Kidney increses acid excretion (NH4) in 2-3 days

Question 18

What causes respiratory alkalosis?

Answer 18

Reduced carbon dioxide

Panic attacks, pregnancy

Question 19

What is the compensatory response to respiratory alkalosis?

Answer 19

Kidney reduces ammonium secretion and eliminates bicarbonate into the urine

Question 20

What changes equally and inversely with plasma HCO3 in respiratory disorders?

Answer 20

Plasma Cl

Question 21

What causes metabolic alkalosis?

Answer 21

Vomiting

Diuretic therapy

Primary hyperaldosteronism

Question 22

How can you differentiate chloride responsive vs resistant metabolic alkalosis?

Answer 22

Responsive - U Cl < 20 mEq / L

Resistant - U Cl > 20 mEq / L

Question 23

What causes the plasma anion gap?

Answer 23

Strong acids dissociate into H+ and A-.

H+ binds HCO3-

Typically A- is excreted in urine and Cl- is responsible for anion gap

Increased anion gap if A- is not excreted

Question 24

What does a high anion gap imply?

Answer 24

Metabolic acidosis

Question 25

What do positive and negative urine anion gaps indicate in metabolic acidosis with normal plasma anion gap?

Answer 25

Positive - Renal tubular acidosis

Negative - Diarrhea

Question 26

What is titratable acid?

Answer 26

The amount of acid excreted with phosphate

Question 27

What is urine ion gap?

Answer 27

Na + K - Cl

Normally positive ~10 mEq/L

Question 28

What is altered in all acid base disorders (except increased plasma anion gap metabolic acidosis)?

Answer 28

Plasma Cl