Fluid Balance Flashcards
what is osmosis
movement of FLUID from high to low concentration
what is diffusion
movement of SOLUTES from greater to lesser concentration
what is filtration
movement of FLUID & SOLUTES from high hydrostatic pressure to low pressure
also known as hydrostatic pressure
what is osmolality
concentration of solutes in a solution
high means more more solutes
what are the 4 main causes of edema
- increased hydrostatic pressure (renal failure, HF)
- decreased colloid osmotic pressure (low albumin)
- increased capillary permeability (infection, burns)
- obstruction of lymphatic system (cancer, infection)
how would fluid volume overload affect the cardiovascular system
- hypertension
- bounding pulses
- JVD
how would fluid volume deficit affect the cardiovascular system
- hypotension, orthostatic hypotension
- weak, thready pulses
- flat veins
- tachycardia
cardiac damage
multi-organ failure eventually
how would fluid volume overload affect the skin
- periorbital edema
- pitting edema
- pale, cool skin
how would fluid volume deficit affect the skin
- sunken eyes
- dry skin: poor turgor & tenting
- dry mucous membranes
- increased body temp
how would fluid volume overload affect the neuromuscular system
- ALOC
- headache
- weakness & paresthesias
how would fluid volume deficit affect the neuromuscular system
- lethargy
- weakness
- coma
cerebral edema, seizures
cerebral hypoperfusion -> ischemic stroke
how does fluid volume overload & deficit affect urine specific gravity
high - low fluids
low - high fluids
what weight change is scary for fluid gain
2-3 lbs in 1 day
5 lbs in 7 days
how does fluid volume overload affect the resp system
- crackles, pulmonary edema
- rapid, SHALLOW RR
how does fluid volume deficit affect the resp system
- rapid, DEEP RR
how does fluid volume overload affect the GI system
- increased motility: diarrhea
- hepatomegaly
- ascites
how does fluid volume deficit affect the GI system
- decreased motility: constipation
- diminished bowel sounds
what are the hypotonic solutions
think lower osmolarity
1/2 NS, 1/4 NS, D5W (isotonic then hypotonic)
what is the use of hypotonic solutions
hypernatremia
what is hypotonic solns contraindicated for
increased ICP
why do we give hypotonic solns slow
SLOW to avoid cellular edema & cerebral swelling
what are the hypertonic solutions
think HIGH & DRY
higher osmolarity
3 NS, D10W, D5NS, D5LR, D5 1/2NS
what is hypertonic solutions used for
hypovolemia
heat exhaustion
peritoneal dialysis
why do we give hypertonic solns slow
to avoid cellular dehydration & avoid fluid volume overload
what is the normal range of osmolality in the body
275 - 295 mOsm/kg
what is starling’s law
hydrostatic and oncotic pressures determine movement across the capillary membrane
what counts as orthostatic hypotension
decrease in 20mmHg systolic, 10mmHg diastolic within 2-5 minutes
what is normal BNP level
below 100
above 400 is definitely HF
what are signs of hypovolemic shock
- cold, clammy, cyanotic skin
- pain somewhere: abdomen, chest
- ALOC
- increased anaerobic metabolism -> lactic acidosis (lactate >4 not good)
how much fluid & sodium restriction should a pt have
fluids: 1.5 - 2L /day
sodium: less than 2g / day
causes for fluid volume deficit
bleed, burns, third spacing
causes for fluid volume excess
polydipsia i.e. SIADH, diabetes insipidus
excess Na intake
