Acid-base

Question 1

Normal H concentration is; every change of _____ pH units represents a change in H by a factor of _____

Answer 1

40 nmol/L, or .00004 mmol/L;

.3, 2

Question 2

Like other important ions, only

Answer 2

free H ion is physiologically active

Question 3

Sponges: when H concentration is high (pH low); when H concentration is low (pH high)

Answer 3

H sponges absorb hydrogen and decrease free H concentration;

H sponges release H and increase the free H concentration

Question 4

____ is the primary buffer in the body:

Answer 4

1. if pH is low, bicarb binds excess H forming H2CO3, which breaks down into water and CO2
2. if pH is high, water and CO2 combine to form H2CO3 which breaks down into bicarb and H

Question 5

HH equation:

Answer 5

pH = pKa + log10 [bicarb]/alpha x pCO2

Question 6

The Mantra:

Answer 6

Acidity = Bicarb/CO2 (A = B/CD)

Question 7

Two independent variables in mantra; 4 different disorders:

Answer 7

Bicarb and CO2;

1. increase bicarb: metabolic alkalosis
2. decrease CO2: respiratory alkalosis
3. decrease bicarb: metabolic acidosis
4. Increase CO2: respiratory acidosis

Question 8

In metabolic disorders, the lungs; in respiratory disorder, the kidney

Answer 8

modify the PCO2;

modifies serum HCO3

Question 9

Compensation always

Answer 9

in same direction as primary disorder

Question 10

Metabolic acidosis/alkalosis:

Answer 10

have bicarb, pCO2, pH go down/up;

Question 11

Respiratory alkalosis/acidosis:

Answer 11

pCO2 down, bicarb down, pH up; pCO2 up, bicarb up, pH down

Question 12

Because of the law of mass action:

Answer 12

compensatory responses do not results in a normal pH; if the patient has a normal pH and both low pCO2/HCO3, that’s a big tip-off for a mixed acid-base disorder

Question 13

Order of looking at values to determine the acid-base disorder:

Answer 13

1. pH greater or less than 7.4
2. Determine if pH, bicarb, CO2 up or down in same direction if metabolic; pH, bicarb, CO2 move in discordant directions is respiratory

Question 14

Direction of compensation is determined by the; magnitude of the compensation is determined by the

Answer 14

direction of the primary disorder;

magnitude of the primary disorder

Question 15

Winter’s Formula:

Answer 15

1.5 x HCO3 + 8 +/- 2;
if expected pCO2 is in range, you have simple metabolic acidosis;
if pCO2 is above expected, you have additional RESPIRATORY ACIDOSIS

Question 16

In respiratory acidosis, the acid is

Answer 16

CO2!!!

Question 17

In anion gap,

Answer 17

Na - (Cl + bicarb)

Question 18

If bicarb goes down in metabolic acidosis, Cl can

Answer 18

increase to compensate to keep normal anion gap; but Cl could stay normal and you have increased anion gap not knowing what the substances are!!!

Question 19

Non-AG metabolic acidosis:

Answer 19

1. chloride intoxication: dilutional acidosis, HCl intoxication, chloride gas intoxication, early renal failure
2. GI loss of bicarb: diarrhea, surgical drains, fistulas, ureterosigmoidoscopy, obstructed ureteroileostomy, cholesterumaine
3. renal loss of bicarb: renal tubular acidosis (proximal, distal, hypoaldo)

Question 20

AG metabolic acidosis:

Answer 20

G: glycols (ethylene, diethylene, propylene)
O: oxoproline (pyroglutamic acidosis)
L: L-lactic acidosis
D: D-lactic acidosis
M: Methanol
A: Aspirin
R: Renal failure
K: Ketoacidosis