Acid-Base - Wall Flashcards Preview

Nephrology > Acid-Base - Wall > Flashcards

Flashcards in Acid-Base - Wall Deck (29):
1

What are volatile acids and how are they excreted?

Carbonic acid

Lungs

2

What are nonvolatile acids and how are they secreted?

Non-carbonic acids (ie phosphoric, sulfuric acid)

Excreted by kidney

3

What is the equation for the bicarbonate buffer system?

CO2 + H20 H2CO2 H + HCO3

4

What is the equation for the hydrogen ion concentration?

H = 24 * CO2 / HCO3

CO2 = 40

HCO3 = 24

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

5

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

7.1 - 80

7.4 - 40

7.7 - 20

6

What is the defintion of a metabolic disorder?

Process that directly alters bicarbonate concentration

7

What is the definition of a respiratory disorder?

Process that directly alters CO2

8

What is the major extracellular buffer?

Bicarbonate

9

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

ECFV - bicarbonate

Urine - Phosphate and ammonia

ICF - Protein

10

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

Respiratory system compenates for metabolic disorders (rapid, minutes)

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

11

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

pH - decreases

HCO3 - decreases (PRIMARY)

pCO2 - decreases (COMPENSATORY)

12

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

pH - increases

HCO3 - increases (PRIMARY)

pCO2 - increases (COMPENSATORY)

13

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

pH - decreases

HCO3 - increases (COMPENSATORY)

pCO2 - increases (PRIMARY)

14

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

pH - increases

HCO3 - decreases (COMPENSATORY)

pCO2 - decreases (PRIMARY)

15

What causes metabolic acidosis?

Decreased renal acid excretion (RTA I, RTA 4)

Direct bicarbonate losses (GI or urine)

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

16

What causes respiratory acidosis?

Hypercapnia (too much carbon dioxide) 

Decrease breathing (ie obstructive pulmonary disease)

17

What is the compensatory mechanism in response to respiratory acidosis?

Buffering raises plasma bicarbonate

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

18

What causes respiratory alkalosis?

Reduced carbon dioxide

Panic attacks, pregnancy

19

What is the compensatory response to respiratory alkalosis?

Kidney reduces ammonium secretion and eliminates bicarbonate into the urine

20

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

Plasma Cl

21

What causes metabolic alkalosis?

Vomiting

Diuretic therapy

Primary hyperaldosteronism

22

How can you differentiate chloride responsive vs resistant metabolic alkalosis?

Responsive - U Cl < 20 mEq / L

Resistant - U Cl > 20 mEq / L

23

What causes the plasma anion gap?

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

24

What does a high anion gap imply?

Metabolic acidosis

25

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

Positive - Renal tubular acidosis

Negative - Diarrhea

26

What is titratable acid?

The amount of acid excreted with phosphate

27

What is urine ion gap?

Na + K - Cl

Normally positive ~10 mEq/L

28

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

Plasma Cl

29