Acid Base Disorders

Question 1

What does pH represent

Answer 1

concentration of free hydrogen ions in circulation

Question 2

What is normal human pH

Answer 2

7.4

Question 3

What is an acid

Answer 3

a molecule that releases hydrogen ions in solution

Question 4

What is a base

Answer 4

any substance that can accept a hydrogen ion

Question 5

How are acids eliminated from the body?

Answer 5

• pulmonary excretion of Co2
• metabolic utilization
• renal excretion of non volatile acids

Question 6

How does the body become acidic

Answer 6

excess CO2 drives the circulation rxn to the right–> increase in H+ ions

Question 7

How does the body become alkalotic

Answer 7

excess HCO3- drives circulation rxn to the left–> decrease in H+ ions

Question 8

What is the equilibrium reaction

Answer 8

CO2+H2O=H2CO3=HCO3-+H+

Question 9

When do you gain hydrogen ions

Answer 9

• increased CO2
• production of phosphoric and sulfuric acid
• loss of bicarb from GI (diarrhea)
• loss of bicarb in urine

Question 10

What causes a loss of hydrogen ions

Answer 10

• emesis

- urine

Question 11

What are common causes of metabolic acidosis

Answer 11

• excess production of lactic acid
• formation of ketone bodies
• loss of bicarb

Question 12

What causes respiratory acidosis

Answer 12

hypoventilation or respiratory disease can result in retention of CO2

Question 13

What causes respiratory alkalosis

Answer 13

hyperventilation–>blowing off CO2

Question 14

What is the anion gap

Answer 14

difference between the plasma concentration of the major measure cation (Na) adn the sume of measured anions (Cl and HCO3)

Question 15

What things can produce excess lactic acid

Answer 15

• severe exercise
• seizure
• shock/hypoxia

Question 16

What things can form ketone bodies in the body

Answer 16

• uncontrolled DM

- fasting states

Question 17

What does the anion gap represent

Answer 17

the concentration of unmeasured anions like phosphates, sulfates, organic acids and proteins

Question 18

What is the normla AG

Answer 18

8-16 mEq/L

Question 19

What is the AG equation

Answer 19

AG= Na- {Cl+HCO3]

Question 20

What does a normal anion gap tell you in metabolic acidosis

Answer 20

excessive bicarbonate loss

Question 21

What causes of metabolic acidosis would show a normal anion gap

Answer 21

• diarrhea
• small bowel, pancreatic or biliary fistula drainage
• ileostomy drainage
• renal tubular acidosis

Question 22

What does an elevated anion gap in metabolic acidosis tell you

Answer 22

excess metabolic acid production

Question 23

What causes of metabolic acidosis would show an elevated anion gap

Answer 23

• lactic acidosis
• DKA
• alcoholic ketoacidosis
• starvation ketoacidosis
• poisoning of toxic alcohols
• kidney dysfuntion

Question 24

What is the most common cause of metabolic acidosis in a hospitalized patient

Answer 24

lactic acidosis

Question 25

What is the cause of type A lactic acidosis

Answer 25

hypoxia–> decreased tissue perfusion–> LA production

Question 26

What types of things cause type A lactic acidosis

Answer 26

• cardiogenic, septic, hemorrhagic shock
• carbon monoxide poisoning
• cyanide poisoning

Question 27

Is type A or type B lactic acidosis more common

Answer 27

type A

Question 28

What causes type B lactic acidosis

Answer 28

impaired cellular metabolism or tissue ischemia without systemic hypoperfusion

Question 29

What things can cause type B lactic acidosis

Answer 29

• DKA
• alcoholism
• infection
• malignancy
• metformin
• bowel necrosis

Question 30

Mnemonic for AG metabolic acidosis

Answer 30

“MUDPILES”

Methanol
Uremia
DKA
Propylene glycol
Isoniazid
Lactic acidosis
Ethylene glycol and ethanol
Salicylates and starvation

Question 31

How do you treat metabolic acidosis

Answer 31

• treat underlying cause

- IV or oral bicarb if severe

Question 32

What can cause metabolic alkalosis

Answer 32

• ingestion or administration of alkali
• stomach loss of H+
• renal loss of H+
• diuretic use (contraction alkalosis)

Question 33

What are the two theories behind contraction alkalosis

Answer 33

1- loss of large volume of bicarb free fluid

Question 34

What is milk alkali syndrome

Answer 34

when a person consumes excessive amounts of milk along with alkaline antacids

Question 35

Why does milk alkali syndrome occur

Answer 35

hypercalcemia reduces the glomerular filtration rate which increases bicarb reabsorption

Question 36

How do you know if an acid base disorder is cause by a respiratory problem

Answer 36

primary defect in a change in pCO2

Question 37

How do you know if an acid base disorder is due to a metabolic problem

Answer 37

primary defect is change in HCO3

Question 38

How do the kidneys respond to acidosis

Answer 38

• bicarb binds H+
• additional H+ are excreted bound to other buffers (hydrogen phosphate)
• new bicarb is formed during tubular glutamine metabolism

Question 39

How do the kidneys respond to alkalosis

Answer 39

• H+ binds bicarb
• bicarb is excreted in the urine
• tubular glutamine metabolism is decreased to lower bicarb productio

Question 40

H+, HCO3-, CO2 change in…

respiratory acidosis
respiratory alkalosis
metabolic acidosis
metabolic alkalosis

Answer 40

Resp acidosis-
       everything increase
Resp alk-
      everything decreased
Met acidosis-
        increased H+
       decreased HCO3/CO2
Met alkolosis-
          decreased H
       increased HCO3/CO2

Question 41

Appropriate HCO3 and PCO2 compensation for…

metabolic acidosis
metabolic alkalosis
acute resp acidosis
chronic resp acidosis
acute resp alkalosis
chronic resp alkalosis

FYI

Answer 41

metabolic acidosis-
HCO3 dec by 1
PCO2 dec by 1.2

metabolic alkalosis-
HCO3 dec by 1
PCO2 dec by 0.4-0.7

A. resp acidosis-
pCO2 inc by 10
HCO3 inc by 1-2

C. resp acidosis
pCO2 inc by 10
HCO3 inc by 3.5

A. resp alkalosis
pCO2 dec by 10
HCO3 dec by 1-2

C. resp alkalosis
pCO2 dec by 10
HCO3 dec by 5

Question 42

What are the steps for determining ABGs

Answer 42

1: acidosis or alkalosis
2: is compensation appropiate?
3: check anion gap