Fluid & Electrolytes

Question 1

Osmosis

Answer 1

water flows from low solute area concentration to high solute area concentration (lower to higher)

Question 2

Diffusion

Answer 2

movement of fluids and solutes from high to low concentration

Question 3

Filtration

Answer 3

movement of movement of fluids and solutes from hydrostatic pressure (changes in pressure pushes solutes to go through area)

Question 4

Osmolality

Answer 4

how much solutes dissolved in a solution based on weight

Question 5

Hormones secreted in Renin-Angiotensin-Aldosterone System (RAAS)

Answer 5

• Low BP / Low Fluid Volume triggers system bc it means body isn’t perfusing
• Kidneys senses this → secretes renin
• Renin converts angiotensinogen from liver → angiotensin I
• Angiotensin-converting enzyme (ACE) from lungs converts angiotensin I → angiotensin II
• Angiotensin II stimulates…
  
  • Vasoconstriction ⇒ increases BP
  • Adrenal cortex to make aldosterone that stimulates K+/Potassium excretion + Na+/Sodium reabsorption which results in water reabsorption bc water follows Na+

Question 6

Normal Electrolyte Levels (Na+, K+, Ca+, Cl-, PO43-, Mg2+)

Answer 6

• Sodium/Na+: 135 - 145 mEq/L
• Potassium/K+: 3.5 - 5.0 mEq/L
• Calcium/Ca+:
  
  • Ionized: 5.5 - 5.6 mg/dL
  • Non-ionized: 9.0 - 10.5 mg/dL
• Calcium/Cl-: 95 - 105 mEq/L
• Phosphate/PO43-: 3.0 - 4.5 mg/dL
• Magnesium/Mg2+: 1.3 - 2.1 mg/dL

Question 7

Hypernatremia Definition

Answer 7

• increased Na+/Sodium lvls (serum sodium > 145 mEq/L)
  
  • Norm: 135 - 145 mEq/L

Question 8

HYPERnatremia Mechanism, Solution, Manifestations

Answer 8

• Mechanism
  
  • Na+/Sodium lvls/concentration outside cells are high which causes water to move out to it ⇒ dehydrates cell
  • Cell is basically dehydrated ⇒ shrivels
  • Water moves from Intracellular Fluid (ICF) to Extracellular Fluid (ECF made of Interstitial fluid and plasma/intravascular fluid)
• Tx: isotonic salt-free fluids
• Manifestations:
  
  • Intracellular dehydration
  • Seizures
  • Muscle twitching
  • hyperreflexia

Question 9

Treatment of hyperkalemia

Answer 9

• Don’t give food that has potassium/K+
• Don’t give meds that promote potassium accumulation/retention:
  
  • Potassium-sparing diuretics
  • Potassium supplements
• Lowering extracellular lvls of potassium:
  
  • Ca+ salt, Glucose, Insulin infusion to stabilize cell wall by…
    
    • Ca+ stabilizes cell wall by allowing insulin to drive potassium back into cells
  • If acidosis present ⇒ infuse sodium bicarbonate
  • Oral or Rectal administration of sodium polystyrene sulfonate (Kayexalate, Kionex) bc it pulls potassium into gut to be excreted
  • Peritoneal or Extracorporeal dialysis

Question 10

HYPOkalemia Manifestations

Answer 10

• Very srs ⇒ eventually cause lots of heart issues
• Membrane hyperpolarization causes… “low and slow” S&S
• Decreased neuromuscular excitability bc K+ important for transmission and conduction of nerve impulses
• Skeletal muscle weakness
• Smooth muscle atony: loss/decrease contraction of smooth muscles ⇒ muscle cramping because loss of K+ helps w/ muscle relaxation
• Cardiac dysrhythmias: K+ important for heart muscle contraction, cardiac rhythms, smooth muscle contraction
• U-wave on ECG
• Hypoactive or absent bowel sounds bc of bowel obstruction bc bowel isn’t moving

Question 11

HYPERkalemia Manifestations

Answer 11

• Means pt is acidotic ⇒ S&S opposite of “low and slow”
• Mild vs. Severe attacks
• Can go into cardiac arrest
• Bradycardic overtime because heart can’t keep up tachycardia
• Neuromuscular wise:
  
  • Paresthesia: tingling
  • Increased deep tendon reflexes: feels like muscles are jittery
  • Increased neuromuscular excitability
• Hyperactive bowel sounds

Question 12

HYPOcalcemia Manifestions

Answer 12

• Increased neuromuscular excitability (partial depolarization):
• Muscle spasms
• Paresthesia: from slow nerve conduction
• Chvostek and Trousseau signs:
  
  • Chvostek: cheek twitching, facial muscle twitch where you tap facial muscle nerve in front of ear
  • Trousseau: hand and wrist spasms, carpal spasms of hand and wrist muscles
• Convulsions
• Tetany: involuntary muscle contractions/spasms

Question 13

HYPERcalcemia Manifestations

Answer 13

• Decreased neuromuscular excitability
• Weakness
• Kidney stones
• Constipation
• Heart block

Question 14

Regulation of calcium and phosphate relationship

Answer 14

• Calcium and phosphate has an inverse relationship: if one goes up, other goes down
• Regulated by 3 hormones:
• Parathyroid & Thyroid hormone:
  
  • Increases Ca+ lvls by having kidneys reabsorb it
  • Activated when Ca+ lvls drop ⇒ works w/ vit D to increase blood Ca+ via reabsorptions
• Vit D: increases Ca+ reabsorption in gut by pulling it from gut and back into vasculature system
• Calcitonin: decreases Ca+ plasma vol so that it has balance in between

Question 15

HYPERtonic solutions

Answer 15

• Hypertonic solutions → causes water to move out of cells ⇒ cells shrivels
• 3% or 5% sodium chloride
• 10% dextrose in water
• 5% dextrose in saline
• 5% dextrose in 0.45% sodium chloride
• 5% dextrose in Lactated Ringer’s
• Used for:
  
  • Severe fluid overload
  • Hyponatremia

Question 16

Isotonic solutions

Answer 16

• Isotonic solutions → balance in/out cells so no fluid shifts/osmosis ⇒ equilibrium
• Saline → 0.9% sodium chloride
• Lactated Ringer’s (LR) → matches osmotic pressure of blood
• Used for:
  
  • Hypotension
  • Fluid replacement/maintenance
  • Post-operative care
  • Hypovolemic shock
  • Hemorrhaging
  • DKA (Type 1 Diabetic Disorder)
  • HHNS (Type 2 Diabetic Disorder)

Question 17

HYPOtonic solutions

Answer 17

• Hypotonic solutions → causes water to move into cells ⇒ cells swell
• 0.45% sodium chloride
• 0.225% sodium chloride
• 0.33% sodium chloride
• 5% dextrose in 0.225% saline
• 5% dextrose in water
• Used for: Cell dehydration (hypernatremic pts w/ sodium lvls >145 mEq/L)

Question 18

Electrolyte levels and what to do with medications if abnormal (i.e. do you hold the medication) à digoxin and hypokalemia?

Answer 18

• If pt is hypokalemic (< 3.5 mEq/L) ⇒ hold digoxin
  
  • Digoxin: HF and cardiac dysrhythmia med increases risk of ventricular dysrhythmia toxicity
  • ↓ K+ lvls allows digoxin to bind more to sodium-potassium ATPase pump on myocytes and inhibits K+ from binding ⇒ ↑ intracellular Na+ ⇒ ↑ Ca+ lvls via sodium-calcium exchanger ⇒ ↑ Ca+ disrupts normal heart electrical conduction system ⇒ dysrhythmias (potentiated digoxin toxicity)