Fluids & Electrolytes

Question 1

Hydrostatic pressure

Answer 1

• pressure based on amount of fluid in vessels (mainly capillaries)
• oncotic pressure outside vessels keeps balance

Question 2

What is osmolality?

Answer 2

Number of particles dissolved in a fluid

ie. serum and urine

Question 3

Types of fluid concentrations

Answer 3

• isoosmolar = balanced, no net movement
• hypoosmolar = more water than solutes (edema)
• hyperosmolar = more solutes than water (dehydration)

Question 4

What is tonicity?

Answer 4

concentration of IV solutions in comparison to osmolality of body fluids

Question 5

What should be considered for fluid replacement?

Answer 5

• all routes of fluid intake and loss
• daily water requirements (2300-2900mL/day for adults)
• water/electrolyte/protein (15-20g/meal) requirements
• pt weight, caloric needs, body surface area
• illness, surgery

Question 6

Types of IV solutions

Answer 6

crystalloids (iso/hypo/hyper), colloids, blood and blood products, lipid emulsions

Question 7

Crystalloids

Answer 7

used for short-term maintenance, dehydration, and electrolyte imbalance

Question 8

Which IV solutions are iso, hypo, and hypertonic?

Answer 8

iso: D5W, 0.9% NaCl (NS), LR
hypo - 0.45% NaCl (1/2 NS)
hyper - 3% NaCl, D5 1/2 NS, D5 NS

LR is similar to blood plasma, D5 1/2 NS is physiologically hypertonic

Question 9

Colloids

Answer 9

big proteins, volume expanders

Dextran, albumin, hetastarch

Question 10

Blood products

Answer 10

• whole blood (~500mL) = everything
• Packed red blood cells (PRBCs) (~350mL) = RBCs w/o plasma and platelets; preferred b/c of O2 carrying capability w/o extra volume
• plasma
• platelets

Question 11

Lipid Emulsions

Answer 11

• phospholipid solutions
• used for parenteral nutrition

Question 12

Electrolyte functions

Answer 12

nerve impulses, muscle contraction, kidney function, ATP production, protein production, acid-base balance, cellular fluid osmolality regulation

Question 13

Potassium

K+

Answer 13

• major intracellular cation
• major electrolyte for cardiac system
• 3.5 - 5 mEq/L
• administered orally, or IV drip (never pushed)
• foods: banana, citrus, tomatoes
• diuretics, laxatives, antibiotics, and steroids can affect levels

Question 14

Hypokalemia

Symptoms mild to severe

Answer 14

• <3.5 mEq/L
• muscle weakness, fatigue, anorexia, nausea, vomitting, paresthesia, leg cramps, decreased bowel motility, palaytic ileus, confusion, rhabdomyolysis, myoglobinuria, dysrhythmias, cardiac arrest, respiratory arrest, death

Question 15

Hyperkalemia

Symptoms mild to severe

Answer 15

• > 5 mEq/L
• dysrhythmias, tachycardia followed by bradycardia, paresthesia of face, tongue, hands, and feet, GI hyperactivity (N/V/cramping), metabolic acidosis

Question 16

Sodium

Na+

Answer 16

• major extracellular cation
• major neurological electrolyte
• 135 - 145 mEq/L
• dietary requirement <2g/day
• foods: processed foods, meats

Question 17

Hyponatremia

Answer 17

• <135mEq/L
• muscle weakness, decreased reflexes, headaches, confusion, lethargy, abdominal cramps, N&V, pallor, dry mucous membranes, cerebral edema, altered mental status, confusion, seizure

corrected via NS, 3% Saline, 5% saline depending on serum sodium level

Question 18

Hypernatremia

Answer 18

• > 145mEq/L
• dry/sticky mucous membranes, flushed/dry skin, agitation, elevated body temp, rough/edematous/dry tongue, N/V, anorexia, tachycardia, hypertension, muscle twitching, hyperreflexia, cerebral dehydration, seizure, coma

Question 19

Calcium

Ca2+

inverse to P, proportional to Mg

Answer 19

• most abundant mineral in body
• major electrolyte for musculoskeletal system
• 8.6 - 10.2 mg/dL total serum
• 4.64 - 5.28 mg/dL ionized
• more than 90% in bones/teeth, half of remaining bound to albumin, rest ionized (free)
• foods rich in vitamin D

acidosis = increased ionized, alkalosis = decreased ionized
decreased albumin = decreased total calcium (ionized unaffected)

Question 20

Hypocalcemia

Answer 20

• <8.6 mg/dL
• anxiety, irritability, tetany, twitching, hyperreflecia, spasms of hands/wrists/feet/ankles, spasmodic contractions, laryngeal spasms, seizures, decreased cardiac output, dysrhythmias

twitch, twitch, seize, seize, chvostek’s, trousseau’s

Question 21

Hypercalcemia

Answer 21

• > 10.2 mg/dL
• fatigue, muscle weakness, hyporeflexia, confusion, impaired memory, anorexia, N/V, constipation, kidney stones, decreased heart rate, dysrhythmias

Question 22

Magnesium

Mg

Answer 22

• maintains Ca2+ and K+ balance
• major for neuromuscular control
• 1.5 - 2.5 mEq/L

Proportional relationship w/ Ca2+

Question 23

Hypomegnesemia

Answer 23

• <1.5 mEq/L
• asymptomatic until ~ 1 mEq/L
• neuromuscular excitability, dysrhythmias, hypertension, tachycardia, v-fib

Question 24

Hypermagnesemia

Answer 24

• > 2.5 mEq/L
• loss of deep tendon reflexes, lethargy, drowsiness, weakness/paralysis, hypotension heart block

Question 25

Chloride

Cl-

Answer 25

• major anion in ECF
• 96 - 106 mEq/L
• acid-base balance, gastric acidity, osmolality of ECF

Question 26

Hypochloremia

Answer 26

• <96 mEq/L
• tremors, twitching, slow & shallow breathing

Question 27

Hyperchloremia

Answer 27

• > 106 mEq/L
• weakness, lethargy, deep & rapid breathing, unconsciousness

Question 28

Phosphorus

Answer 28

• major anion in ICF
• 2.4 - 4.4 mEq/L
• bone/teeth formation, neuromuscular activity, cellular osmotic pressure, acid-base balance, DNA/RNA, intracellular energy transfer

inverse relationship w/ Ca2+

Question 29

Hypophosphatemia

Answer 29

• <2.4 mEq/L
• muscle weakness, tremors, paresthesia, bone pain, hyporeflexia, seizures, hyperventilation, anorexia, dysphagia, hemolytic anemia, platlet dysfunction, reduced oxygen transport

Question 30

Hyperphosphatemia

Answer 30

• > 4.4 mEq/L
• hyperreflecia, tetany, flaccid paralysis, muscular weakness, tachycardia, nausea, diarrhea, abdominal cramping, chronic kidney disease