Fluid and Electrolytes Flashcards Preview

662 > Fluid and Electrolytes > Flashcards

Flashcards in Fluid and Electrolytes Deck (70)
Loading flashcards...

Sodium disorders (___- ____) 


  • 135-145
  • Predominant cation of the ECF
  • Primary electrolyte in establishing osmostic pressure between the ICF and ECF
  • All body fluids are in osmotic equilibrium and changes in serum sodium concentration (Na) are associated with shifts of water in and out of body fluid compartements 
    • Adding Sodium in the intravascular compartment from the interstitial fluid and, ultimately from ICF


Sodium disorder

A pts Na concentration should not be used because it doesnt reflect?

Na imbalances cannot be properly assesses without?

Na disorders are ___ disorders?

Normal sodium maintenance is? 

  • Not be used as an index of sodium because it does not reflect total body sodium content, Na primarily reflects disturbances in TBW
  • Without first assessing the body fluid status 
  • Water disorder
  • 80-120 meq/day 


Hyponatremia: Signs and Symptoms 

Usually exhibited at < 120 meq/L 

Usually as <110 

  • Agitation 
  • Fatigue
  • HA
  • Muscle cramps 
  • Nausea/anorexia


  • Confusion 
  • Seizures
  • Coma 


Hypertonic Hyponatremia

Usually associated with _____ 

Treat the ___ as this is corrected the [Na] will?


Treat the hyperglycemia na with return to normal 


Diagnostic algorithm for hyponatremia 


Diagnostic algorithm for hyponatremia 



Calculation of sodium deficit in a 75 kg male with a serum sodium of 123 mEq/L

Sodium deficit = (45 liters)(140 mEq/L - 123 mEq/L) = 765 mEq



Causes of Hypernatremia

First 4 lead to?


  1. Dehydration = loss of hypotonic fluid (respiratory, skin losses)
  2. Decreased water intake
  3. Osmotic diuresis
  4. Diabetes insipidus (decreased ADH activity)
    1. May be induced by certain drugs (lithium, phenytoin)
  5. Latrogenic- Admin of too mich hypertonic saline-uncommon


Hypernatremia treatment

Calculate TBW deficit?

replace deficit over? with?

  • Water def= Normal TBW - Present TBW
  • Over 48-72 hours with solution hypotonic to pts serum 


Hypernatremia treatment

Overly-___ correction may lead to?

The rate at which hypernatremia should be corrected depends on the severity of symptoms and the degree of?

For ____ pts, the rate of correction probably should not exceed?

Rule of thumb?


  • Rapid may lead to cerebral edema and death
  • Hypertonicity
  • Asymptomatic, 0.5 mEq/L/hour
  • Replace half the calculated deficit with hypotonic solutions over 12 to 24 hours 


Hypernatremia example

Calculate the water deficit in a 75 kg patient male with a serum sodium of 156 mEq/L

Water Def (L) = TBW x [(serum sodium/140)-1]

45 x 0.1 = 5 L


Calcium disorders (__-__)

Ca and phos concentrations regulated by?

Normal calcium maintenance requirement 

Corrected calcium accounts for? Calculation?

  • 9-10.5 mg/dL
  • Parathyroid hormone (Increased, increases calcium concentration
  • Vit D
  • Calcitonin increased, decreases calcium 


Maintenance- 800-1200

CC- accounts for a decrease in percent of protein binding due to decrease albumin concentration

CC= observed [Ca] + 0.8 (normal albumin*-observerd albumin)

Normal = 4 g/dL


Hypocalcemia sign/symptoms and causes


Checking Trousseaus Signs?

  • Apply a BP cuff to pts upper arm and inflate
  • Pt will experience adducted thumb, flexed wrist and metacarpophalangeal joints
    • Carpopedal spasm=tetany


Checking for Chvosteck signs

  • Tap on pts focial nerve adjacent to the ear
  • Brief contraction of upper lip, nose, or side of face indicated tetany 


Calcium supplements


IV calcium replacement products which one is preferred and why?

How are they given?

Calcium gluconate- preferred less irritating

Calcium chloride- irritating to veins-->central line


Preparation given as slow push or added to 50 mL to 250 mL .9% NaCl, LR, D5W for slow infusion 


Indications for IV calcium for Acute Hypocalcium 

  • Pt symptomatic (patesthesia, tetany, Chvostek sign)
  • Clinically relevant hypocalcemia (serum Ca < 1 mmol/L)
  • Massive blood transfusion (especially with preexisting cardiac disease)
  • CCB overdose
  • Receiving inotropic or vasopressor support
  • Emergent hyperkalemia 


Hypocalcemia treatment

Acute symptomatic hypocalcemia

  • 200-300 mg of elemental calcium IV and repeat until symptoms fully controlled 
    • 1 gram of calcium chloride or 2-3 grams of calcium gluconate
    • No faster then 30-60 mg of elemental calcium per minute
    • Caution if serum phosphate elevated or if on digoxin therapy 


Hypercalcemia treatment

  • Consider if pt symptomatic and/or serum concentration > 12 mg/dL
  • 0.9% NaCl +- furosemide
    • Infusion rate as high as 200-300 ml/hr may be needed
    • Only ass loop diuretic after initial ECF depletion has been corrected
    • Function kidney needed (hemodialysis alternative)
    • Monitor [K] and [Mg] Carefully 


Treatment strategies and modalities for Hypercalcemia


Suggested treatment regimens for Hypercalcemia

  • Because of polyuria, pt is usually dehydrated
  • Normal saline 200-300 mL/hr, checking for continued dehydration or fluid overload. Goal: up tp 4 L on day one
  • Once rehydrated, add furosemide (Block Ca reabsorption) 40-80 mg IV Q 1-4 hours until urine output = 200-250 mL/hour
  • Monitor serum K and Mg 


Phosphorus disorders (___-___)

Express phosphate in mg or mmoles not milliequivalents

# of mmoles = 

Normal maintenance phosphate requirement

  • 3-4.5 mg/dL
  • = amount in mg/ atomic moleculat wt
  • 800-1200 mg/day (250 mg = 8 mmol)


Hypophosphatemia treatment

  • Mild 2-2.5
    • Eat
  • Moderate 1-2.5 
    • Oral therapy
      • 1.5-2 grams/day divided into 3-4 doses
      • Diarrhea may be dose limiting
  • Severe <1
    • Parenteral therapy indicated
      • .o8-.64 mmol/kg
      • Range 5-45 over 4-12 hours
      • Select replacement based on need for other electrolytes (Na vs. K)
      • Caution in pts with hypercalcemia, renal dysfunction, or evidence of tissue injury
      • Switch to oral supplement when level 2-2.5 mg/dL


Phosphate replacementproducts


 IV Phosphate repletion protocol


Hyperphosphatemia treatment

  • Dietary restriction of phosphate and protein
  • If tetany (spasms) administer calcium salts IV (see hypocalciemia aboce)
  • Diaylsis of caused by renal failure
  • Oral phosphate binders
    • Mg hydroxide (milk of Mg)
      • Can cause diarrhea
    • Calcium carbonate
      • Inexpensive, tablen can be crushed 


5 phosphate binders for treating hyperphosphatemia

  1. Mg hydroxide (milk of Mg)
    1. Can cause diarrhea
  2. Calcium carbonate (tums)
    1. inexpensive, tablets can be crushed
  3. Calcium acetate 
    1. 2 tabs/each meal 
  4. Sevelamer carbonate
    1. Cationic polyer, contains neither Ca ot Al
    2. 800-1600 mg/each meal
  5. Lantanim carbonate
    1. Initial dose 250-500 mg PO 3 x daily to max 3750 mg/day
    2. most need 1500-3000 mg/day 


K dissorders (___-___) 

Normal maintenance

3.5-5 mEq/L

0.5-1 mEq/kg/day or 40-50 mEq/day 


Causes of hypokalemia