Acid base

Question 1

independent vs dependent acid-base variables:

Answer 1

The independent variables: SID, Atot, pCO2
The dependent variables: [HCO3-], [A-]

Question 2

law of electroneutrality means

Answer 2

sum of cations = sum of anions

Question 3

main cations and anions in blood

Answer 3

• Main Cations are Na+, K+ (also Ca++, Mg++)
• Main Anions are Cl-, HCO3-, proteins (A-), but can also include lactate and other molecules (“unmeasured anions”)

Question 4

what does a gambleegram of plasma show us?

Answer 4

Useful way to visualize ion concentrations in
watery solutions, to illustrate the Law of Electroneutrality

cations: Na+ & K+
anions: Cl-, HCO3-, lactate, A-

Question 5

SID equation and meaning

Answer 5

SID=Na+K–Cl, Ref=40

Strong Ion Difference = Na + K – Cl
- SID <40 causes metabolic acidosis
- SID >40 causes metabolic alkalosis

Question 6

SID impact on blood pH

Answer 6

-low SID, low PH
-high SID, high pH

Question 7

Anion Gap equation, and what it represents

Answer 7

AG = SID - HCO3, Ref=12-17
Note: HCO3 and tCO2 are roughly the same!

AG represents A- + unmeasured anions

Question 8

important note about HCO3 and tCO2

Answer 8

(note: HCO3 is roughly equal to tCO2 on a biochemistry profile)….

Question 9

A- equation and reference, meaning

Answer 9

A- =0.2xTP, Ref = 13-17

> A- low causes hypoproteinemic alkalosis and decreased Anion Gap
A- ­ high causes hyperproteinemic acidosis and increased Anion Gap

Question 10

significance of protein (A-) value

Answer 10

Ø Plasma proteins have acid-base effects
Ø Proteins (A-) have net negative charge, are weak electrolytes, and at normal acid-base balance constitute the majority of the anion gap (AG)
> A- low causes hypoproteinemic alkalosis and decreased Anion Gap
> A- ­ high causes hyperproteinemic acidosis and increased Anion Gap

Question 11

Proteins (A- ) impact on blood pH

Answer 11

• low [protein], more alkalotic
• high [protein], more acidotic

Question 12

SIG equation and reference

Answer 12

SIG=AG – A-, ref = 0-2
(represents unmeasured anions)

Question 13

Potential causes of high Strong Ion Gap

Answer 13

ü Lactic acidosis (D- or L-lactate)
ü Ketoacidosis (diabetic ketoacidosis, alcohol abuse)
ü Renal Failure
§ uremia
§ increased acid excretion, decreased HCO3 reabsorption
§ accumulation of sulfates, phosphates, urate

Toxins:
§ Methanol, ethylene glycol, propylene glycol § Aspirin
§ Phenformin (Old metformin)
§ Iron, isoniazid, cyanide

Question 14

EFFECT OF CHANGING SID ON HCO3-

Answer 14

low [SID], more acidotic, lower HCO3
high [SID], more alkalotic, higher HCO3

Question 15

EFFECT OF CHANGING Protein (Atot) ON HCO3-

Answer 15

Low [Atot], more alkalotic, higher HCO3
high [Atot], more acidotic, lower HCO3

Question 16

PCO2 impact on HCO3

Answer 16

CO2 has very little net effect on metabolic compensation

Question 17

what is SIG? what is the major component?

Answer 17

Strong Ion Gap = AG – A-
Ø D- or L-Lactate is the major component of SIG

Question 18

pCO2 has big effects on [___] but little effect on [___]

Answer 18

pCO2 has big effects on [H+] but little effect on [HCO3-]

Question 19

If SID, pCO2 and A- abnormalities occur concurrently in same animal, it is common to have ____ acid-base disorders

Answer 19

If SID, pCO2 and A- abnormalities occur concurrently in same animal, it is common to have mixed acid-base disorders

Question 20

Calves get acidosis due to:

Answer 20

• Na+ down
• Cl- normal or up
• Lactate up (D-, L-lactate)
• TP up

Question 21

Practical Estimation of degree of metabolic acidosis present in calves with diarrhea in field:
-how do things vary with age?

Answer 21

• The more depression the greater the acidosis
• Calves > 1week have much
  greater acidosis compared to calves < 1week of age with similar clinical signs