Fluids and electrolytes

(total body water) sum of all fluids within body, 45-80% of body weight. Fat cells=less water. muscle cells=more water

intracellular fluid 2/3 of bodily fluids

extracellular fluid. 1/3. interstitial fluid (between cells 2/3). Intravascular fluid (blood vessels) 1/3. Miscellaneous body fluids (lymph joints csf intestinal)

homeostasis, maintaining volume balance, maintaining solute/electrolyte concentrations (osmolarity) balance, Maintaining pH acidity basicity

a substance dissolved in a solution (lemon water)

a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute resulting in a solution. (the water, in sugar water)

a homogeneous mixture composed of 2+ substances dissolved in a solvent (the lemonade)

• Hypertonic=concentrated
• Hypotonic=diluted
• Isotonic=balanced

neurons in the hypothalmus (regulate concentrations to 2% changes, releases antidiuretic hormone)

antidiuretic hormone: increases the permeability of renal tubular cells to water so water can be reabsorbed where needed

• Dehydration: to little
• Overhydration: to much
• Balanced: normovolemic
• regulated within 10% by RAAS and natriuretic factors

Renin-angiotensin-aldosterone system: kidney signals that volume is low by secreting renin. Angiotensinogen from liver meets renin and forms angiotensin 1. Ace (angiotensin converting enzyme) from surface of lungs and kidneys converts angiotensin1 to angiotensin 11. this signals everything to reabsorb water.

usually hold proteins and cells in and are permeable to O2 CO2 H2O and glucose. (liver more, Brain less, more during inflammatory response)

pushes water

pulls water

principal force determining movement of water. (attraction of particles in solution for water) water moves toward the compartment where the number of particles is the greatest

• filtration: movement of fluid out of the capillary into interstitial space
• reabsorption: movement of fluid back into the capillary from the interstitial space

forces favoring filtration:capillary hydrostatic pressure and interstital oncotic pressure - forces opposing filtration= capillary oncotic pressure and interstitial hydrostatic pressure

• excessive accumulation of fluid within interstitial spaces
• lymphatic obstruction (post-mastectomy scarring)
• inflammation (anaphylaxis)
• increased hydrostatic pressure in vessels (excessive iv, chronic renin activation)
• decreased osmotic concentration of the blood(starvation)

• isotonic dehydration: vomiting diarrhea bleeding, orthostatic hypotension, flat neck veins, dizziness, weight loss
• isotonic overhydration: CHF(congestive heart failure), renal failure, excessive iv fluid, edema, weight gain, destended neck veins

• Hypernatremia: gain in sodium or loss of water (almost always accompanied with dehydration)results in intracellular dehydration
• Causes:salt water, hypertonic saline, oversecretion of aldosterone (keep salt in)
• Symptoms: thirst fever dry membranes, confusion lethargy seizures

• Hyponatremia: sodium loss, inadequate sodium intake, or water excess
• Causes: vomiting diarrhea (pure sodium deficit, intake of large omounts of water, iv fluids to much water not enough sodium
• Symptoms: lethargy confusion decreased reflexes

• ECF: concentration 3.5-5.5 mEq/L
• ICF 150-160 mEq/L
• Maintained my sodium potassium adenosin, triphophatase pump, can be secreted by distal tubul of kidneys and by colon

• K+ <3.5 mEq/L
• Causes:low intake, laxative abuse, diarrhea, ecf leaking, alkalosis (metabolic or respiratory)
• Symptoms: with severe losses, muscle weakness/loss <3

• K+>5.5 mEq/L
• Causes: increased intake, leak into ecf (crushing injury), decreased renal excretion
• Symptoms: neuromuscular irritability (restlessness, cramping, weakness, paralysis)

• Isotonic
• 0.9% NaCl (normal saline)
• 5% Dextrose (D5W)
• 5% Dextrose in 0.225% NaCl
• Lactated Ringers

• Hypertonic
• 5% Dextrose in 0.9% NaCl- Hypertonic
• 5% Dextrose in 0.45% NaCl- Hypertonic
• 10% Dextrose (D10W)-Hypertonic

• Hypotonic
• 0.45% NaCl (1/2 normal saline)-Hypotonic