Pharm Test III 2
Terms
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- Which IV fluid is the most similar to ECF?
- Lactated Ringer's
- Which IV fluid is the safest to give to pts?
- 1/2 Normal Saline
- Two isotonic solutions
- NS and LR
- Name the three hypotonic solutions
- D5W, 1/2 NS, D5 1/2
- Name the two hypertonic solutions
- Na Lactate, 3%
- What does "isotonic" mean?
- the same concentration inside and outside of the cell
- Osmolarity/tonicity are measured in what?
- mEq
- ECF and ICF have what type of tonicity?
-
Isotonic - normal osmolarity ranges =
ECF=280-310, ICF=350-400 - Major intracellular cation
- Potassium (K+)
- This is defined as fluid/Na lost ineven amounts in ECF with no ICF shift.
- Isotonic dehydration
- A BUN/Creatinine >30 suggests what?
- Dehydration (isotonic dehydration)
- A BUN/Creatinine of 20-30 suggests what?
- a renal problem
- Causes of isotonic dehydration
- Anything that can cause you to lose fluid - third spacing, vomiting, diarrhea, polyuria, gastric suction, hemorrhage, fever
- What is "third space shifting"?
- fluid located within organ spaces where fluid is not normally located (ascites, peritonitis, burns)
- Which fluid should a pt with an electrolyte imbalance NOT receive? Why?
- LR. It contains many electrolytes that can further exacerbate a pt's imbalance.
- S/Sx of isotonic dehydration
- Altered mental status, weight loss, dry mucous membranes, increasd BUN/CR, decreased BP, decreased skin turgor
- Treatment of isotonic dehydration
- underlying cause, isotonic fluid replacement, monitor I/O, LOC, VS, BUN, CBC, electrolytes
- Why monitor CBCs in pt w/isotonic dehydration?
- To see if pt is bleeding and establish if that is the cause of dehydration
- This is defined as fluid/Na+ gain in even amounts in ECF with no ICF shift (excessive fluid accumulation)
- Isotonic Overhydration
- Causes of isotonic overhydration
-
-CHF, CRF, Liver Dz.
-Too much Na+
-Too much hypertonic soln.
-Too many saline enemas, corticosteroids (solumed, pred) - S/Sx Isotonic Overhydration
- Peripheral edema, polyuria, acute weight gain, JVD, ascites, increased BP, decreased HCT
- Why would a pt's HCT be decreased in isotonic overhydration
- it becomes diluted with the excess fluid accumulation
- Treatment of isotonic overhydration
-
-underlying cause
-less fluids
-diuretics
-I/O, VS, CXR, HEMATOCRIT!!!, BUN - Why do you want to do a CXR on a pt w/ isotonic overhydration?
- assess for pleural effusion or pulmonary edema
- What is the urine excretion goal in a pt w/isotonic overhydration?
- 1 ml/kg/hr (max)
- Serum levels of hypokalemia
-
mild = 3 - 3.5
Moderate = 2.5 - 3
Severe = < 2.5
meq/L - What is the transcellular shift seen in hypokalemia?
- ECF ---> ICF
- How is Lithium associated with hypokalemia?
- Lithium is a salt. It competes with K+ for excretion.
- Causes of hypokalemia
-
-Loop diuretics -Stress
-Laxative abuse -Amphotericin
-Lithium -hypothyroid
-Liquor (alcohol)
-Liver - What other electrolyte deficiency will hinder the increase of potassium?
- Magnesium - if K+ will not increase, check Mg+ levels and fix those first
- What is Amphotericin B and what is it's relationship to hypokalemia?
- anti-fungal used to treat infections that works on Mg+. May inhibit a rise in K+ levels due to decrease in Mg+ levels.
- The "biggest" cause of hypokalemia?
- diuretics
- S/Sx of hypokalemia
-
-anorexia -EKG change
-drowsiness -leg cramps
-paresthesia -lethargy
-digoxin toxicity - Why is insulin/glucose therapy a cause of hypokalemia?
- insulin draws potassium into the cell
- What drug reverses Digoxin toxicity?
-
Digibind
(0.8-1.2 = normal dig.) - Treatment of hypokalemia
-
-underlying cause =
-hypomagnesemia
-give K+ supplement
-K+ sparing diuretic - Potassium level is low and your digoxin level is high...what is this called?
- Digoxin toxicity
- Digoxin is an antiarrhythmic that works on the ATPase pump. T/F?
- True
- Serum levels for hyperkalemia
-
Mild = 5.5 - 6
Moderate = 6.1 - 6.9
Severe = >7
mEq/L - What is the trancellular shift seen in hyperkalemia?
- ICF ---> ECF
- Causes of hyperkalemia
-
-CRF or ARF
-tumor lysis syndrome
-burns/tissue trauma
-metabolic/lactic acidosis - How do burns/tissue trauma cause hyperkalemia?
- the cellular breakdown involved releases excess K+
- What SE does dig. toxicity cause visually?
- halos around objects (think Van Gogh)
- What drugs cause the lactic acidosis involved in hyperkalemia?
- Metformin (glucophage)
- What is the fastest way to give a pt K+ supplements if IV is not available?
- Liquid form
- T/F = It is OK to give a pt IV form of K+ IVP.
- False. NEVER give K+ IVP. Always infuse = 10/mEq/30min (fastest) or 20mEq/hr
- What is added to IV K+ to reduce the "sting" involved in it's administration?
- "Nute" (added sodium bicarb)
- What is the best way to give K+ supplement?
- Always try to give it orally ("if your gut works, use it") - if any other funky changes (EKG, ALOC, etc.), then give IV INF
- What can happen if you give K+ INF too fast?
- it can cause an arrhythmia
- What are the weakest diuretics?
- Potassium Sparing (least amount of water loss)
- What is an example of a potassium-sparing diuretic?
-
Spironalactone (Aldactone)
Triemetrine (Dyazide) - Why do you never give calcium to a pt that is Dig. Toxic?
- It can cause "Stone Heart" - a condition where the heart becomes calcified and does not pump. If dig level is too high, DO NOT give Calcium
- What are some drug-induced causes of hyperkalemia?
-
-K+-sparing diuretics
-NSAIDS
-dig. toxicity
-ACEI/ARB - Which is more critical - hyper or hypokalemia.
- Hyperkalemia
- S/Sx of hyperkalemia
-
-N/V/D
-paresthesias
-EKG
-confusion - What is Addison's Dz.?
- A syndrome involving aldosterone secretion that causes an increase in potasiium levels.
- What is the "biggest" cause of hyperkalemia?
- Acute renal failure/chronic renal failure
- How does Tumor Lysis Syndrome (TLS) cause hyperkalemia?
- Pt with tumor that is undergoing chemo - cells are rapidly broken down causing excess K+ to be released
- Acute hyperkalemia that is considered moderate or above (over 6)= what medication do you give the pt?
- Calcium gluconate 10%
- Why do you give calcium to a pt with acute hyperkalemia that is considered moderate or above?
- It is cardio-protective (assists is contractions/reduces arrhythmias)
- If your pt is hyperkalemic and is presenting with metabolic acidosis, what drug do you give?
-
Sodium Bicarb (HCO3)
- 50mL IVP over 10 minutes
- or add to bag and infuse over 1 hr. - If the potassium does not drop within an hour after your initial interventions for hyperkalemia, what do you do next?
-
Start an insulin drip
-100 units/100mL (1U/mL) or D10W - T/F - Both insulin and dextrose draw potassium into the cell.
- True.
- **What is another name for Kayexelate and what is it?
- Sodium Polyesterene. A sorbitol or sugar-based product
- How is Kayexelate given?
- 30 gm Orally or 50 gm by enema
- When is Kayexelate given?
- Given to moderate hyperkalemic pts. that do not have the severe symptoms (EKG changes, etc.) b/c it takes 1-2 hrs to work.
- How does Kayexelate work?
- The sorbitol binds to the K= and excretes it in the feces
- If the hyperkalemia does not go down despite all pharmacological efforts, what should you do for the pt?
- Dialysis - will probably give Kayexelate in conjunction with the dialysis.
- Serum level that marks hyponatremia.
- <135 mEq/L
- What is the fluid shift involved in hyponatremia?
- ECF ---> ICF (causes cellular swelling)
- S/Sx of hyponatremia
-
-CEREBRAL EDEMA -resp. arrest
-orthostasis
-confusion (key)
-seizures at 118
-pitting edema - Three types of hyponatremia
-
-Hypovolemic (low Na, low TBW)
-Euvolemic (normal Na, high TBW)
-Hypervolemic (high Na, high TBW - What is SIADH
- Syndrome of inappropriate anti-diuretic hormone
- What drug is used to help pt's with SIADH?
- Desmopressin
- Drugs that can cause hyponatremia
- Vasopressin, NSAIDS, SSRIs, Clonidine (Alpha II agonist), TCAs
- Treatment for hypovolemic and euvolemic hyponatremia
-
isotonic saline (NS) 1.5-2 mEq/L/hr until resolved
Goal = Na+ of 120 or better - If the Na+ level is below 118 (and you fear seizures), what soln. may you give?
- 3% hypertonic soln
- What happens if you give 3% hypertonic saline too fast?
- may cause Central Potine Myelating Disorder - hurts cerebellum which impairs mov't and can cause paralysis
- Treatment of Hypervolemic Hyponatremia
-
-3% hypertonic soln
-diuretics
-fluid restriction - Serum level that distinguishes hypernatremia
- >145 mEq/L
- What is the fluid shift in hypernatremia?
- ICF ---> ECF (cell shrinks)
- S/Sx of hypernatremia
- -restlessness, weakness, tachycardia, flushed skin, delirium, decreased salivation & tears
- Three types of Hypernatremia
-
-Hypovolemia (low Na, low TBW)
-Euvolemic (normal Na+, low TBW)
-Hypervolemia (high Na, norm TBW - What types of pt's are on osmotic diuretics?
- Pt's with increased ICP or pts with increased cerebral edema (hyponatremia)
- What is the only extrarenal cause of hypernatremia?
- Skin. (sweating)
- T/F - NSAIDS decrease Na+ (so you can use them to treat hypernatremia) but you avoid them in pt's that are hyperkalemia
- True.
- What are some causes of hypervolemic hypernatremia?
-
-improper formulas (feeding tubes)
-hyperaldosteronism - Treatment for hypernatremia?
- Loops, D5W, poss. dialysis
- Where is 60-70% of body fluid (water) exchanged in the kidney?
- Loop of Henle
- What are the strongest diuretics?
- loops