FE Flashcards
Water content of body % lean vs fat women vs men age
50-60
more in lean than in fat
less in women bc more fat
less in old ppl bc less lean (45-50%)
Body Fluid Compartments
Intracellular (2/3) (28 L)
Extracellular (1/3)
- Interstitial fluid (10 L)
- plasma (3 L)
- lymph
- transcellular fluid (in joints, bt peritoneae, CSF) –> 1 L
Fluid gain/loss
1 L = 2.2 lbs = 1 kg
240 ml = 8 oz = 0.5 lb = 0.23 kg
Fasting makes adults lose 1-2 lbs per day –> any extra weight loss is fluid
Main electrolytes for ECF and ICF
ECF: sodium! (little K, Ca, Mg) —> Cl (little HCO3, sulfate, PO4)
ICF: K (little Mg and Na) —> PO4 (little HCO3)
Diffusion
Facilitated Diffusion
Active Transport
- movement of molecules from high to low conc –> no energy
- uses prot carrier to pass molecules thru membrane –> high to low conc –> no energy
- movement against conc gradient –> needs energy –> Na/K pump
Osmosis
osmotic pressure
osmolality
osmolarity
- movement of water down conc radient –> no energy
- “pull” of water (higher in areas of high solute conc) mOsm
- number of milliosmoles per kg of water
- mOsm/L of solution
Osmolality
Pretty much the same for all body fluid spaces
Normally 280-295 mOsm/kg
High means water deficit
Low means water excess
Plasma osmolality = (2 x Na) + (BUN / 2.8) + (glucose / 18)
hydrostatic pressure
oncotic pressure
Force of fluid in compartment pushing against cell membrane or vessel wall (e.g. BP) –> decreases as nears capillaries
(colloidal osmotic pressure) osmotic pressure created by colloids in solution (e.g. albumin) –> 25 mm Hg in plama; 1 mm HG interstitial spaces
Factors affecting fluid movement in capillaries
- capillary hydrostatic pressure (40 to 10) –> higher at arterial end
- plasma oncotic pressure (25)
- interstitial hydrostatic pressure (1)
- interstitial oncotic pressure (1)
Edema
shifts of plasma into interstitial spaces:
high venous hydro pressure,
low plasma oncotic pressure,
high interstitial oncotic prssure
fluid spacing
distribution of body water
First spacing: normal ICF and ECF distribution
Second spacing: abnormal accumulation of interstitila fluid
Third spacing: excess fluid in nonfunctional areas bt cells
How much water do we need per day?
What is insensible water loss?
2000-3000 ml
invisible vaporization from lungs and skin to regulate body temp (not the same as sweating which includes electrolytes)
Hypothalamic Pituitary fluid regulation
ADH release stimulation
Osmoreceptors in Hypothalamus stimulate thirst and release of ADH from post pit
ADH acts on distal tubules and collecting ducts to make them more permeable to water (water excess suppresses ADH)
low BP, nausea, pain, hypoglycemia, hypoxemia
Renal regulation of fluid
kidneys filter plasma volume many times a day
reabsorb 99% of filtrate and make 1.5 L of urine a day
fucked up kidneys cause edema, K or PO4 retention, acidosis, etc
Adrenal cortical fluid regulation
Glucocorticoids (cortisol) increase serum glucose levels
Mineralocorticoids (aldosterone) enhance Na retention and K excretion
-RAA
-high K
-low Na
-ACTH
Gastrointestinal Regulation of Fluid
GI tract secretes 8000 mL of digestive fluid a day
Usually reabsorbs the fluid
Diarrhea and vomitting lead to significant fluid loss (AND ELECTROLYTES)
Old people and fluid regulation
kidneys change shape which slows glomerular filtration rate, less able to concentrate urine or conserve water
Less renin and aldosterone –> more ADH and ANP
Thin skin = moisture loss
Fluid Volume Imbalances
NG suction
ECF deficit = hypovolemia
ECF excess = hypervolemia
loss of Na, K, H, and Cl –> low fluid volume and alkalosis
cardiac fluid regulation
ANP and BNP are made by cardiomyocytes in response to increased atrial pressure and high serum sodium —> antagonists to RAAS and suppress Ald, ADH, and Angio II
fluid volume defecit vs dehydration
dehydration = loss of pure water
fluid volume defecit (hypovolemia) = loss of body fluid via diarrhea, vomitting, hemorrhage (includes electrolytes)
ECF volume deficit causes and manifestations
Casues
- insensible water loss bc fever or heat
- diabetes insipidus
- osmotic diuresis
- hemorrhage
- GI losses
- too many diuretics
- not enough water drunk
- 3rd space fluid shifts : burns and pancreatitis
Manifestations
- restless, sleepy, CONFUSION
- thirsty –> dry mouth
- cold clammy skin
- bad capillary refill
- postural hypotension, high pulse, low pressure
- little, concentrated pee
- breathing fast
- weak, dizzy
- weightloss
- seizures, coma HYPOVOLEMIC SHOCK
ECF Volume Excess: causes and manifestations
Causes:
- excess isotonic or hypotonic IV fluids
- heart or renal failure
- primary polydipsia
- SIADH
- Cushing syndrome
- Too many corticosteroids
Manifestations
- headache, confusion, lazy
- edema
- jugular distension
- S3 heart sound
- bounding pulse, high BP and CVP
- Polyuria
- dyspnea, crackles, pulmonary edema!!!!!!!!!!!!!!
- spasms
- weight gain!!!!!!!!!!!!!!!!!!!!!!!!
- seizures and coma
treating ECF excess and defecit
Defecit: 0.9% NaCl or lactated Ringers solution
Excess: diuretics and no sodium and fluid restriction (also paracentesis and pleural effusions)
Nurse implementation of fluid balance
daily weights
intake and output
-urine specific gravity: over 1.025 is concentrated; less than 1.010 is diluted
Lab findings
- ECF defecit has high BUN, Na, and hematocrit
- ECF excess had decreased all of those things
Cariovascular care
Respiratory care
Patient safety
Skin care
Cardiovascular care (fluid)
ECF excess: bounding pulse, distended jugular, high CVP, high BP, S3 sounds
ECF defecit: high HR, peripheral vasoconstriction. orthostatic hypotension
Respiratory Care
Pulse oximetry and auscultate lungs
excess = pulmonary edema, shortness of breath, and crackles defecit = increases RR
Fluid defecit and patient safety
- risk of falling
- muscle weakness
- if orthostatic hypotension, make them change position slowly
- put alarm monitors on confused patients
skin care
Edema analysis
Good skin care
Defecit = low skin turgor (tenting) –> test sternum, abdomen, and ant forearm –> not as relavent in old ppl bc their skin isn’t as elastic
=cold and moist skin
-dry mucous membranes
Edeman assessed with thumb and forefinger over tibia, fibula, sacrum
1+ = slight edema (2 mm indent)
4+ = pitting edema (8 mm indent)
No extreme heat change positions elevate edema don't use too much soap moisturize
Fluid therapy
give IVs –> be careful of rate esp heart, renal, or brain problems
defecit: offer drinks every 1-2 hrs –> make bathroom access easy if they’re worried ab nocturia –> help ppl hold containers
