hyper/hypo K+

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hyper/hypo K+
2013-03-29 15:56:11
BC Boston College CRNA chem lytes

BC Boston College CRNA chem: lytes
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  1. What lytes are responsible for the resting membrane potential?
    Na+ and K+
  2. What is the normal intracellular concentration of K+?
    150 mEq/L, is the MAJOR intracellular Ion
  3. What it the normal plasma concentration of K+?
    3.5 to 5 mEq/L
  4. What is the difference between serum and plasma?
    • plasma is the portion of the blood that has not clotted
    • serum indicates portion of blood that has clotted
  5. What is the Serum K+ concentration?
    .5mEq higher than plasma because of lysis of cells
  6. What maintains the high K+ gradient in the cell?
    the Na+/K+ ATPase pump
  7. The ATPase pump moves 3 Na+ ions out of the cell for every___ K+ ions into the cell. Why is ATP needed?
    2, K+ is moving against the gradient.
  8. What two substances help to move K+ into the cells?
    • Insulin
    • Beta agonists
  9. Acidosis both metabolic and respiratory will shift K+ where?
    out of the cells
  10. Where does metabolic and respiratory alkalosis shift K+?
    into the cell
  11. How much K+ does the average person take in each day?
    50 - 150 mEq/day
  12. How is K+ excreted from the body?
    • mainly through the kidney's
    • some through the faecal route
  13. T or F: We usually excrete about the same amount of potassium that we take in per day?
  14. How low does GFR need to be to ineffectively clear K+?
  15. What are the MAJOR regulators of k+?
    • Aldosterone
    • plasma K+
  16. What needs to be considered with a pt on an ACEI?
    HyperK+, because aldosterone is blocked thereby increasing K+.
  17. What drugs often cause hypokalemia?
    • diuretics
    • antibiotics
    • various hormones
    • chemotherapeutic drugs (less common)
  18. Is plasma concentration a good indicator of total body K+?
  19. T or F: Acute hypoK causes hyperpolarization of the cell.
  20. What maintains the relative negativity of the cell membrane?
    Na/K ATPase pump
  21. What is normal charge inside the cell?
    -70 to -90 mVolts inside the cell
  22. Hyperpolarization makes it more difficult for the cell to generate an action potential. What lyte imbalance causes this?
  23. How do the sedative hypnotic drugs work?
    by hyperpolarizing the cell membranes in the CNS via Cl- ions when they attach to the GABA receptor.
  24. What is Threshhold?
    The charge at which an action potential is generated
  25. What is the consequence of hyperpolarizing the cardiac cell membranes of the normal pacemakers via hypok+?
    could see some ventricular escape beats
  26. What ECG changes might we see with hypok?
    • flat or inverted T's
    • prominent U's
    • ST depression
  27. Pt's on Digoxen may be at risk for increase dig toxicity because of what?
    hypoK causes more binding of dig
  28. A high Na and K diet can contribute to what?
  29. How does HypoK affect Diabetic pt's?
    • impaired insulin secretion
    • decreased organ sensitivity to insulin
  30. Is there a suggested level of K below which surgery is contraindicated?
    not really
  31. We can expect to more rhythme disturbances below what level of K?
    3.5, especially cardiac pt's
  32. Treatments for hypo K
    • potassium replacements
    • correction of acid base balance
    • removal of medications creating problem
  33. What is hyperK?
    > 5
  34. How much does a normal dose of succ increase the K level?
    .5 of a mEq
  35. Why does succ increase the K level?
    the fasiculations of succ cause a release of Intracellular K into the interstitium.
  36. What pt population is at increased risk for hyperK due to succ admin, why?
    • Denervation injury
    • burn pt's
    • result of upregulation of cholinergic receptors, Succ is contraindicated
  37. Below what level of K is the effect of succ on the heart minimal?
    6 mEq however we might see tall peaked T's
  38. As the level of K rises what occurs with the ECG tracing
    first tall peaked T's then lengthened PR, followed by a more sine wave appearance QRS eventually leading to cardiac standstill
  39. What imbalances increase K's effect on the heart?
    hypoNa+, Hypo Ca++, or acidosis
  40. K levels above 7 present with what specific problems?
    • Flaccid paralysis
    • impaired phonation
    • Resp Arrest
  41. What meds cause an elevated K?
    • NSAIDS
    • ACEI
    • K sparing diuretics
  42. What predisposing factors will make a pt more prone to hyperK?
    • Renal insufficiency
    • Diabetes
    • hypoaldosteronism (same mechanism as ACEI)
  43. How do we treat hyperK?
    • Eliminate the cause
    • reverse membrane ecitability
    • remove K from body
    • move K+ from ECF to ICF Via Glucose and insulin
  44. What does Ca-gluconate do in lieu of hyperK?
    • Depresses cardiac excitation
    • stabilizes the rhythm
  45. How do Beta2 agents help in hyperK?
    Increase skeletal uptake of Ca++. (albuterol)
  46. How can we remove K from the body?
    • Furosemide if kidneys are functioning
    • dialysis
    • Kayexalate