Looks like no one added any tags here yet for you.
body water content
60% of body weight in adults
80% of body weight in neonates
body water intracellular
66%
body water interstitial (around the cells)
28%
body water in blood vessels
5%
signs of continues loss of body water
loss of moisture from the skin (results in tenting)
sunken appearance
drying of mucous membranes
Normovolemia
adequate body water volume or normal hydration
maintained by ensuring input is equal to output
measurable losses
urination
other secretory functions- sweat, tears , saliva, feces, vaginal secretions, gland seceretions
non measurable losses
evaporation from the body surface (skin, eye , mucus membranes)
during respirations
body water is lost when
high ambient temp
dry arid environment
increased exercise
fever
open body cavities
certain pathological processes (vomit, diarrhea, diuresis, bleeding)
adult water maintenance
60ml/kg//day
pediatric maintenance
120ml/kg/day (2x adult)
maintenance volume
the volume of water that we require for daily survival
pathology occurs when
excessive water loss
lack in intake
excessive intake
hypovolemia
dehydration
hypervolemia
overhydration
overhydration
aka water intoxication
uncommon to rare
overhydration causes
iatrogenic - (excessive fluid therapy)
endocrine problems
behavioral overconsumption
overhydration pathological changes
increased volume in blood vessels
decreases oncotic and osmotic pressures in blood vessels
fluid leaves blood vessels and enters interstitial space
decreases osmotic pressure in the interstitial space
fluid enters the cells
overhydration pathological effects
increased demand on the heart (increased water added to blood vessels increases BP)
diuresis
increased urine production
Pulmonary hypertension
fluid enters in lungs and pleural space
due a combination of high BP and decreased oncotic pressures in the blood vessels
if heart can’t push fluid through fast enough there will be increases pressure in pulmonary vessels;s, if significant may force fluid into lungs and pleural space
pulmonary edema
increased fluid in the lungs
Pleural effusion
fluid in the pleural space (around the lungs)
cerebral edema and brain compression
increased water causes the concentration of Na to drop and this decreases the osmotic pressure in the interstitial space
water moves from extracellular space into intracellular causing the cells to swell
swelling of cells causes cerebral edema and compression
Clinical signs of cerebral edema
increased HR, BP, RR
dyspnea- increased resp effort
increased and dilute urine
neurological signs (headache, behavioural changes,ataxia, tremors, blindness, seizures, coma)
Patients at risk for overhydration
heart failure
kidney failure
end stage liver failure
small animals
treating overhydration
stop fluids
diuretics - drugs that promote urine production
correct any underlying endocrine condition
dehydration
the body loses more water than it takes in
causes of dehydration
not drinking enough
any form of water deprivation
animals forced to “drink snow”
animals in drought conditions
increased losses
lactating animals require more water
animals that are athletes
hot weather, hyperthermia, prolonged fever
vomit, diarrhea
renal losses
iatrogenic( diuretics)
blood loss
small animals
diagnosing dehydration
history
PE finding
diagnostic tests
history
very important for determining cause
owner can comment on amount and duration of losses
owner to comment on availability and water intake
PE findings
assessing hydration is part of every PE
hospitalized patients should be evaluates at least once daily
minimum exam includes
weight changes
CRT
MM texture
skin tent
HR
diagnostic tests
increased pack cell volume
increased total proteins
increased urine concentration
degree of dehydration
clinical signs that are noted with diagnostic test results
<3% dehydrated
subclinical
no changes on PE
long term may later production and performance
changes appear on diagnostic tests
treatment - drink water
3-5% dehydrated
mild
often subclinical
if clinical- lethargic, maybe tacky MM or weight change
changes on diagnostic testing
diagnosis often based on history
treatment oral fluids
5-8% dehydrated
moderate
weight loss, lethargic,prolonged CRT, tacky MM, mild skin tent,
clearly seen on diagnostics
treatment- IV fluids
8-10% dehydrated
marked
weight loss, lethargic to depressed, prolonged CRT, tacky to dry MM, skin tent, mild tachycardia,may look sunken
clearly seen on diagnostics
treatment - IV fluids and correct electrolytes
10-12% dehydrated
severe
significant weight loss, depressed, prolonged CRT, dry MM, skin tent, sunken eyes, tachycardia, cool extremities
diagnostic tests show other changes to electrolytes and other organ functions
treatment Iv fluids and organ support
>12% dehydrated
Moribund
this animal is in shock and dying
treatment shock fluids, possible CPR
method 2 calculation based on body weight loss
works best for animal is hospitalised or been seen within days
calculation should always match up with clinical signs
deficit volume
teh volume of fluids that’s lacking in a dehydrated patient
needs to be replaced to return to normal
Pathology associated with dehydration
danadge is related to decreased blood pressure that causes decreased tissue perfusion. tissue cells receive less oxygen and nutrient delivery, decreased removal of metabolic waste products
Hypernatremia
increased Na concentration causes body water to shift compartments