Acid-Base Disorders - Exam 2

Question 1

what does pH represent?

Answer 1

the concentration of free hydrogen ions (protons) in circulation

Question 2

normal pH?

Answer 2

7.4

Question 3

pH needs to be maintained at what and for what?

Answer 3

maintained at 7.35-7.45 for optimal functioning of body cells

Question 4

pH >7.4 means?

Answer 4

alkalosis (basic)

Question 5

pH <7.4 means?

Answer 5

acidosis (acidic)

Question 6

what is an acid?

Answer 6

a molecule that releases H+ ions (protons) in solution

Question 7

what is a base?

Answer 7

any substance that can accept a hydrogen ion -> removes free protons from solution

Question 8

how do you eliminate acids in the body?

Answer 8

pulmonary excretion of CO2 (when breathe out, breathe out CO2)

metabolic utilization of organic acids

renal excretion of nonvolatile acids (combine H+ ions w/ buffers)

Question 9

how does the kidney excrete acids?

Answer 9

by combining H+ ions with buffers

Question 10

what are buffers?

Answer 10

chemicals that bind to H+ ions to excrete them from kidney

Question 11

if have excess CO2, what occurs in the equilibrium rxn?

Answer 11

Excess CO2 drives the reaction to the right -> increase in H+ -> acidic

Question 12

if have excess bicarb (base), what occurs in the equilibrium rxn?

Answer 12

Excess bicarb drives the reaction to the left -> decrease in H+ -> alkalotic

Question 13

how do you gain hydrogen ions?

Answer 13

increased CO2

production of phosphoric and sulfuric acids (metabolism of proteins and other organic molecules)

loss of bicarb from GI losses (ex: diarrhea)

loss of bicarb in urine

Question 14

how do you loss hydrogen ions?

Answer 14

loss of hydrogen ions from emesis (b/c stomach is acidic environment and vomit a lot, lose H+ ions and become alkaloid)

loss of hydrogen ions in urine

Question 15

how can changes in CO2 levels occur?

Answer 15

hypoventilation or rest diseases (ex: obstructive) or hyperventilation

Question 16

how does hypoventilation or obstructive respiratory diseases cause changes in CO2 levels and what change?

Answer 16

they result in retention of CO2 -> respiratory acidosis

Question 17

causes of respiratory acidosis?

Answer 17

obstructive lung diseases (ex: COPD), septic, any condition where can’t blow off CO2

Question 18

how does hyperventilation cause changes in CO2 levels and what change?

Answer 18

in hyperventilation you are blowing off CO2, resulting in respiratory alkalosis

Question 19

what causes respiratory alkalosis?

Answer 19

states of anxiety - panic attacks

blow off excessive CO2

Question 20

common causes of metabolic acidosis?

Answer 20

excess production of lactic acid (>4mEq/L): severe exercise or seizure or shock/hypoxia

formation of ketone bodies (uncontrolled DM or fasting states)

loss of bicarb (diarrhea)

Question 21

what is the anion gap?

Answer 21

difference between the plasma concentration of the major measure cation (Na+) and the sum of the measured anions (Cl- and HCO3-)

Question 22

anion gap equation?

Answer 22

AG = Na - [Cl + HCO3]

Question 23

what does the difference in the anion gap represent?

Answer 23

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

Question 24

normal AG?

Answer 24

8-16mEq/L

Question 25

what does an elevated anion gap mean?

Answer 25

that someone has excessive elements in their blood that shouldn’t be there

Question 26

what causes you to lose a base and have a normal anion gap metabolic acidosis?

Answer 26

excessive bicarb loss (intestinal losses)

renal losses (renal tubular acidosis)

Question 27

what causes you to gain an acid and have an elevated anion gap metabolic acidosis

Answer 27

excess metabolic acid production (lactic acidosis, DKA, alcoholic ketoacidosis, starvation, poisoning with toxic alcohols like ethylene glycol)

impaired elimination of metabolic acids; kidney dysfunction

Question 28

what is the most common cause of metabolic acidosis in hospitalized patients?

Answer 28

lactic acidosis

Question 29

what are the 2 types of lactic acidosis?

Answer 29

Type A lactic acidosis (hypoxic) - M/C

Type B lactic acidosis

Question 30

what is the most common type of lactic acidosis?

Answer 30

Type A (hypoxic)

Question 31

what is Type A (hypoxic) lactic acidosis? Examples?

Answer 31

Decreased tissue perfusion í increase LA production

-Ex: Cardiogenic, septic, hemorrhagic shock; Carbon monoxide or cyanide poisoning

Question 32

what is Type B lactic acidosis? Examples?

Answer 32

Impaired cellular metabolism or tissue ischemia without systemic hypoperfusion

Ex: DKA, alcoholism, infections, malignancy, metformin, bowel necrosis (important reason to check LA)

Question 33

mnemonic for AG metabolic acidosis

Answer 33

• M - methanol
• U - uremia (indication for urgent hemodialysis) í uremia is from severe kidney dysfunction
• D - DKA
• P - Propylene glycol
• I - Isoniazid
• L - Lactic acidosis
• E - Ethylene glycol and ethanol (alcoholic ketoacidosis)
• S - Salicylates (aspirin) and starvation

Question 34

metabolic acidosis treatment?

Answer 34

treat underlying cause

-consider admin of IV or oral sodium bicarb if severe

Question 35

causes of metabolic alkalosis?

Answer 35

ingestion or administration of alkali (CaCO3 or bicarb - ex: Tums)

stomach loss of H+ (vomiting)

Renal loss of H+ (excess mineralocorticoids -> primary hyperaldosteronsim, cushings)

diuretic use

milk alkali syndrome

Question 36

2 theories of contraction alkalosis d/t diuretics?

Answer 36

Theory #1

• Loss of large volumes -> Quantity of bicarbonate remains constant -> concentration increased
• When diuresis a pt, losing a lot of fluid which is bicarb free, so have increased concentration of bicarb b/c now have less fluid

Theory #2
-Renal compensation for volume loss -> increased renin -> increased angio II -> increased aldosterone -> decreased potassium -> intracellular shift of protons

Question 37

diuretic use can cause what?

Answer 37

contraction alkalosis and impaired chloride reabsorption

Question 38

what is impaired chloride reabsorption?

Answer 38

Diuretics block Cl reabsorption and further enhances NaHCO3 reabsorption (instead of NaCl)

Question 39

what is milk alkali syndrome?

Answer 39

• Persons who consume excessive amounts of milk (Ca2+) along with alkaline antacids (ex: tums)
• Hypercalcemia reduces glomerular filtration rate which increases bicarb reabsorption
• Alka-seltzer contains sodium bicarb

Question 40

treatment for metabolic acidosis?

Answer 40

• Treat underlying cause

- Remove or reduce offending agent

Question 41

if have respiratory problem, primary defect is change in what?

Answer 41

pCO2

Question 42

if have metabolic problem, primary defect is change in what?

Answer 42

HCO3