acid-base, electrolytes

Question 1

severe acidosis can cause?

Answer 1

is less than 7.2
1) hypotension via direct myocardium and smooth muscle depression, reducing cardiac contractility and peripheral vascular resistance.
2) hypoxia of tissues
3) ventricular fibrillation threshold is decreased
4) hyperkalemia - K moves extracellularly in exchange for hydrogen moving intracellularly
5) CNS depression - LOC, seizures

Question 2

severe alkalosis can cause:

Answer 2

when ph greater than 7.6
1) hypoxia of tissues
2) hypokalemia - H moves extracellularly shifting K intracellularly
3) hypocalcemia - cardiovascular depression and neuromuscular irritability

Question 3

how to manage electrolyte disturbances

Answer 3

1) delay elective surgeery
2) non elective surgery
- ekg monitoring,
- hemodynamic monitoring
- labs, correct lab and underlying
- avoid rapid correction of sodium to prevent Osmotic demyelination - pretty sure this is irreversible ( max is 8meq/L over 24 hour period, often raising serum sodium by 4-6 men/L can alleviate sx and prevent herniation.)
- avoid sux and LR can raise serum potassium in the setting of hyperkalemia

Question 4

management of hyperkalema

Answer 4

if no ekg changes check labs and make sure no hemolysis and then if no hemolysis then remove potassium (step 3)
if ekg changes:
1) calcium gluconate- within minutes to antagonize the heart
2) 10 U of insulin with 50% dextrose to prevent hypglycemia- shifts k intracellular
- beta 2 adrenergic agonists to shift potassium intracellular
- 1-2 amp of sodium bicarb over 10 minutes to shift K intracellular
3) get rid of K via loop diuretics, dialysis if needed and kayexalate

Question 5

hypokalemia

Answer 5

check mag- correct mag if low
oral K
IV k no faster than 10mEq/hour in peripheral veins, central can be faster but no more than 20 mEq/hour to avoid cardiac sensing of hypERkalemia.

Question 6

low mag effects what electrolytes

Answer 6

can see low K and Ca