• The larger of the 2 body fluid compartments
• 2/3 total body water

Composition of body fluid compartments

• ·   Intracellular fluid (ICF) = K⁺ and Phos

• 1/3 total body water
• Separated into 2 compartments:

interstitial fluid and intravascular fluid

• These compartments are separated by a membrane that is freely permeable to water

Concentration of major cations and anions

• ·   Extracellular fluid (ECF) = Na⁺ and Cl^-

• represents the fluid surrounding the cells in the various tissues of the body
• includes water contained within bone and dense connective tissue
• accounts for 75% of the ECF

AKA Plasma

accounts for the remaining 25% of ECF

• Ionic composition of ISF and IVF are similar
• However, the major difference is IVF contains more proteins

1.  Isotonic solutions

(0.9% NaCl and Lactated Ringer's)
2.  Hypotonic solutions

(Hypotonic saline and Dextrose solutions)
3.  Hypertonic solutions

(Hypertonic saline)

1. Albumin (5% and 25%)
2. Hetastarch
3. Dextran

Can lead to hyperchloremic metabolic acidosis

Can lead to hypernatremia and cellular dehydration

• More physiological and thus preferred for surgeries
• contains K (4 mEq/L) and Ca2+ (3 mEq/L)

• numberous IV medication incompatibilities and cannot be run in the same line or used for admixture
• Cannot be administered with blood transfusions b/c the Ca2+ in LR neutralizes the citrate anticoagulant used in blood products

• Good for maintenance fluids
• Good for IV medication admixtures
• NOT useful for rapid intravascular volume expansion due to greater distribution into intracellular fluid compartments

• Good for maintenance fluids
• Good for IV medication admixtures
• Dextrose is quickly metabolized by the body allowing for free flow of water across all membranes

• should never be used for volume resuscitation due to small percentage that remains within the intravascular compartment
• Can lead to hyperglycemia - caution in patients with DM or glucose intolerance

Used for:

1. symptomatic hyponatremia
2. treatment to decrease intracranial pressures - pulls fluid into vasculature to relieve intracranial pressure

• Limited use due to risks of excessive increases in plasma sodium concentration leading to osmotic demyelination
• Should not be used for initial volume resuscitation or for maintenance fluids
• dose and rate can be calculated to avoid rapid increase in serum Na and avoid complications with osmotic demyelination

1. colloids remain primarily within the intravascular fluid compartment
2. colloids pull additional fluid into the intravascular space by oncotic pressure

expands intravascular compartment 3x that of equal amounts of isotonic crystalloids

Volume resuscitation

3x volume expansion effect of normal saline

• Shifts fluid from intracellular and interstitial compartments into the intravascular space
• Used in patients with hypovolemia in the face of interstitial edema (hypotension during hemodialysis, ascites, etc.)

1. pulmonary edema
2. hypocalcemia
3. anaphylaxis

Volume expansion

volume expansion is equivalent to 5% albumin

• inhibits factor VII and von Willebrand factor
• defects become more pronounced as doses increase
• max daily dose = 1500 mL

Which of the following is/are NOT ADRs for Hetastarch?

1. hypoamylasemia
2. anaphylaxis
3. pulmonary edema
4. dose-independent bleeding

1 and 4

hetastarch causes HYPERamylasemia -->

• no alteration in pancreatic function but levels 2x ULN for up to 5 days

hetastarch causes dose-RELATED bleeding tendencies -->

• inhibits factor VII and von Willebrand factor, defects become more pronounced as doses increase

volume expansion

Dextran has which of the following similarities with Hetastarch?

1. Dose-related bleeding tendencies (inhibits factor VII and von Willebran factor)
2. False increase in blood glucose, total protein, bilirubin
3. Enhances fibrinolysis
4. Acute renal failure
5. Anaphylaxis
6. Interferes with blood cross matching

1 and 5

1 through 6 are all ADRs with Dextran but only 1 and 5 overlap with hetastarch

1.  Dose-related bleeding tendencies

(inhibits factor VII and von Willebran factor)
2.  False increase in blood glucose, total protein, bilirubin
3.  Enhances fibrinolysis
4.  Acute renal failure

(due to osmotic diuresis effect)
5.  Anaphylaxis

(more common than other colloids)
6.  Interferes with blood cross matching

Which of the following is considered the correct mEq/L value for 0.9% NaCl?

1. 77, 154
2. 154, 77
3. 154, 130
4. 50, 50
5. 154, 154

1.  Maintenance therapy

replaces ongoing losses of water and electrolytes under normal physiological conditions

2.  Replacement therapy

corrects existing water and electrolyte deficits, such as GI losses, excessive urinary losses, bleeding, 3rd spacing, etc.)

Monitor continuously for s/sx of hypovolemia or hypervolemia

Goal is to preserve water and electrolyte balance

1.  if there are s/sx of hemodynamic instability (drop in BP, tachycardia)

and/or

2.  if there are s/sx of hypovolemia

Which of the following is/are FIRST-LINE for fluid replacement therapy?

1.  25% albumin

2.  Hetastarch

3.  3% NaCl

4.  D5W

5.  0.9% NaCl

6.  0.45% NaCl

7.  Dextran

8.  Lactated Ringer's

5 and possibly 8?

• in ronald's hand out, it says first-line fluids for fluid replacement are isotonic fluids
• however, it was mentioned earlier that LR has many problems (IV incompatibilities, interactions with drugs, cannot be given with blood transfusions) so my guess is 0.9% NaCl would be first-line and not LR

General Recommendations for fluid replacement:

note: there is no formula to accurately estimate total fluid deficit and amount that will be needed for resuscitation

mild to moderate hypovolemia: 1-3x basal fluid requirements

severe or hemodynamical instability: 500-1000 mL boluses until patient stable, then 2-3x maintenance rate

Which of the following is recommended for a patient that is hemodynamically instable and has chronic kidney disease?

1. intitiate 0.9% NaCl 1-3x basal fluid requirements only

2.  initiate dextran at 15 mL/kg/day

3.  start D5W at basal fluid requirements

4.  500-1000 mL boluses untils stable then adjust maintenance rate based on patient response

4

Note the above question is also true for ESRD and heart failure

For which of the following situations would it be wise to use a colloid?

1.  if the patient has pulmonary edema

2.  if the patient is experiencing 3rd spacing

3.  if the patient had a hemorrhage

4.  if the patient was experiencing hemodynamic instability

5.  if the patient's BP is 159/98, consistently

1. diarrhea
2. vomiting
3. diuretics (loops > thiazides)
4. hypomagnesemia
5. insulin
6. metabolic alkalosis
7. beta-agonists

Which of the following causes an intracellular shift of K+ that results in hypokalemia?

1.  glucagon

2.  dobutamine

3.  insulin

4.  metabolic acidosis

5.  metabolic alkalosis

1.  EKG changes such as:

ST flattening

t-wave inversion

wide QRS

2.  life threatening arrhythmias

3.  heart block

4.  ventricular fibrillation

5.  lowered threshold for digoxin toxicity

6.  patients will cardiac diseases are more susceptible

7.  paralysis, respiratory depression, rhabdomyolysis

A patient has a K+ level of 2.0 mEq/L.  How many mEq of K+ should be given to get the patient to a level of 3.5 mEq/L?

1.  100 mEq

2.  150 mEq

3.  50 mEq

4.  200 mEq

150 mEq

10 mEq KCl would result in a serum K+ rise of 0.1 mEq/L

If a patien has acute renal failure/CKD, how would that affect the amount of K+ we give to the patient that is hypokalemic?

1.  this would not affect the amount

2.  increase the initial dose by 100%

3.  give the patient a bolus of 100 mEq KCl and see what happens

4.  reduce the initial dose by 50%

What is the goal serum level for a patient with cardiovascular disease?

1.  3.5 - 4.0 mEq/L

2.  >4.0 mEq/L

3.  >5.0 mEq/L

4.  3.0 - 4.0 mEq/L

recheck K levels 1-2 hrs

What electrolyte should be monitored for and replaced in order to treat hypokalemia?

1.  K+

2.  Ca2+

3.  Cl-

4.  Mg2+

the answer is 4

hypokalemia will not be able to be treated unless serum Mg2+ is checked and subsequently replaced

1. dietary, K supplements, IV fluids with K+
2. metabolic acidosis, beta-blockers, digoxin overdose
3. renal failure, ACEI/ARBs, K-sparing diuretics, NSAIDs

most patients asymptomatic untilo K+ > 5.5 mEq/L

1. EKG changes (peaked t-waves, prolonged p-r interval, wide QRS)
2. life-threatening arrhythmias (ventricular fib, asystole)
3. pt's with cardiovascular disease more susceptible
4. ascending paralysis

1. cardioprotection
2. intracellular shift of K+
3. increase potassium loss from body

1. alcoholism, malnutrition
2. prolonged diarrhea
3. loop diuretics, amphotericin B

• the slower the rate of magnesium administered, the more that is reabsorbed by the kidney
• if there is a rapid increase in serum concentration with a bolus of Mg --> the kidney will excrete Mg in response to the elevated serum Mg levels

> 2.5 mg/dL

rare and usually iatrogenic (induced accidently by healthcare professional)

1. renal insufficiency
2. excess Mg intake - PO, IV, medications, TPN

What is the dose limiting ADR of oral magnesium therapy?

1.  HTN

2.  diarrhea

3.  constipation

4.  hyponatremia

2 is the answer

divide daily doses --> bid to qid

1. hypotension
2. bradycardia
3. EKG abnormalities
4. lethargy
5. drowsiness
6. hypotonia

1. hyporeflexia
2. somnolence
3. coma
4. hypocalcemia

1. respiratory depression
2. heart block
3. asystole

1. cardioprotection
2. increase Mg excretion from body

1. phosphate binding meds, chronic diarrhea
2. hyperparathyroidism, metabolic acidosis
3. refeeding syndrome, chronic alcoholism, recovery from diabetic ketoacidosis, sepsis

1. imparied diaphragmatic contractility and acute respiratory failure
2. paralysis
3. cardiac arrhythmias and decreased cardiac contractility

1. dietary including TPN
2. tumor lysis syndrome, rhabdomyolysis
3. renal failure, hypoparathyroid, bisphosphonates

initial s/sx of hypocalcemia due to phosphorous binding

chronic hyperphosphotemia can result in soft tissue calcifications when Ca x Phos > 55

moderate to severe symptoms:

1. NVD
2. lethargy
3. seizures
4. renal failure due to Ca-Phos precipitation in kidneys

Which of the following is the hallmark clinical manifestation of hypocalcemia?

1. tetany
2. muscle cramps
3. bradycardia
4. seizures
5. laryngeal spasms

1 is the correct answer

all of the choices are acute clinical manifestations but only tetany is the hallmark clinical manifestation

1. depression, anxiety, memory loss, confusion
2. hair loss, grooved and brittle nails
3. eczema and dermatitis

Which of the following belong to Ca gluconate 10% and Ca chloride 10%

1.  In an emergency situation, 1 amp can be infused over 4 minutes

2.  Extravasation risk

3.  Central line only

4.  Can be used in peripheral or central line

1 and 4 belong to Ca gluconate

2 and 3 belong to Ca chloride

When a patient has chronic asymptomatic hypocalcemia, which of the following should be done?

1.  Give IV Ca gluconate

2.  Give vitamin D in addition to help with absorption

3.  Use PO products

4.  Give continuous infusion at a rate of 2.5 - 3 mEq/min

2 and 3 are correct

1 and 4 are used if patient has acute, symptomatic or severe hypocalcemia with serum calcium < 7.5 mg/dL

1.  hyperparathyroidism, vitamin D intoxication, renal failure

2.  thiazide diuretics, calcium supplements, lithium, Al/Mg antacids

1.  constipation, nausea

2.  oliguric renal failure, nephrolithiasis/obstruction

3.  mild drowsiness, depression, lethargy, stupor, coma

4.  ventricular arrhythmias

1. metastatic calcifications
2. nephrolithiasis
3. chronic renal insufficiency

• Hypercalcemia produces an osmotic diuresis leading to prerenal acute renal failure due to hypovolemia
• hypovolemia reduces Ca excretion in the urine and leads to a rapid rise in serum Ca
• Volume infusion reverses hypovolemia and promotes renal Ca excretion as well as helps to prevent Ca precipitation within the kidneys

• Saline infusion alone will not provide the desired decrease in serum Ca levels 
• furosemide increases urine excretion of Ca
• it also helps to prevent fluid overload 

• As adjunctive therapy - especially in cases when saline and loop diuretics are not solutions to the underlying cause (malignancy, hyperparathyroidism)
• Inhibits bone resorption
• Used for rapid reduction - but mild response and will not be effective alone for cases of malignancy

• adjunct to calcitonin - especially in cases of malignancy, renal failure, and vitamin D toxicity
• impedes growth of neoplastic tissue
• decreases GI calcium absorption, increases urinary calcium excretion and decreases bone resorption

• potent inhibitor of bone resorption
• mainly for hypercalcemia of malignancy
• delay onset inhibits use as an agent for acute/symptomatic control
• used as adjunctive therapy to calcitonin and corticosteroids

What type of hypercalcemia (acute or chronic) are bisphosphonates used for and what is the rationale?

1.  chronic - has delayed onset of action

2.  chronic - cannot be used with other hypercalcemia agents

3.  acute - has quick onset of action

4.  acute - better tolerated for acute therapy

What is mithramycin's place in hypercalcemia therapy?

1.  first-line agent

2.  can be used in patients with ARF

3.  reverses hyperparathyroidism

4.  short-term treatment in patients not responsive to alternate therapies

In what conditions should mithramycin be avoided?

1.  Acute Renal Failure

2.  Hepatic failure

3.  Platelets < 30,000

4.  all of the above