fluid/electrolyte + acid/base Flashcards
what is fluid made up of
water and electrolytes
where is fluid in the body
2/3 = ICF (within cells) 1/3 = ECF (tissues, blood vessels, interstitial)
what is CHP
capillary hydrostatic pressure
“push pressure”
pressure fluid exerts on vessel walls
what is OP
osmotic pressure
“pull pressure”
pressure coming from solute that draws fluid into vessels
what is CHP affected by
blood pressure and blood volume
what is OP affected by
plasma protein concentration
what is edema
accumulation of fluid from the vascular space moving into the interstitial space (tissues)
causes of edema
- increased CHP (volume, BP)
- increased capillary permeability (inflm, malignancy)
- decreased OP (low proteins d/t renal problems)
- obstructed lymph node (malignant obstruction, surgical removal)
what is dehydration
decreased interstitial and intravascular fluids
volume deficit
causes of dehydration
- inadequate fluid intake
- 3rd space loss
- GI fluid losses (n+v)
- skin losses (perspiration, burns)
- renal losses (kidney failure)
what is 3rd spacing
fluid accumulation in transcellular space
ex. joints, lungs, spinal cord, abdominal cavity
what is pH measuring
hydrogen ion concentration
what is normal blood pH
- 35-7.45
7. 4
what are the pH regulating mechanisms
- lungs
- kidneys
- buffers
alkalosis is
increased base
pH > 7.45
> 7.8 = death
acidosis is
increased acid
pH < 7.35
< 6.8 = death
how do the lungs regulate pH
- exhale CO2
- chemoreceptors detect PCO2, alter ventilation
- rapid, 50-70% effective
- failure: CO2 buildup = increased carbonic acid = acidosis
how do the kidneys regulate pH
- excrete H (acid), reabsorb HCO3 (base)
- takes hours to days to respond
how do buffers regulate pH
- system of trading a strong acid for weak acid, strong base for weak base
- immediate response
respiratory imbalances involve
volatile acids (carbonic acid)
metabolic imbalances involve
fixed acids
lactic, HCl
inadequate ventilation will cause
- increased PCO2
- decreased pH
- respiratory acidosis
hyperventilation will cause
- decreased PCO2
- increased pH
- respiratory alkalosis
causes of metabolic acidosis
severe diarrhea
renal failure
causes of metabolic alkalosis
vomiting, excess antacid intake
acid/base compensation formula
CO2 + H2O <> H2CO3 <> H + HCO3
if the kidneys fail what happens
metabolic acidosis
H builds up, the rxn moves to the left, CO2 and water are exhaled to restore pH
if the lungs fail what happens
respiratory acidosis
CO2 builds up, the rxn moves to the right, H is excreted and HCO3 is reabsorbed to restore pH
what is the homeostatic balance ratio
20 bases: 1 acid
10 bases : 1 acid
acidosis
25 bases : 1 acid
alkalosis
treatment for pH imbalance
- oral and IV fluids
- must address underlying cause
causes of respiratory acidosis
- depressed respiratory status (opioids)
- lung disease
causes of respiratory alkalosis
- hyperventilation
- altitude
- fever
- anxiety
