4. Hydration

Question 1

How much of the body is water? in adults, in neonates?

Answer 1

60% in adults, 80% in neonates

Question 2

What is the distribution of body water?

Answer 2

66 ICF
33 ECF
5 in blood vessels

Question 3

List the maintenance rates for adult k9, feel, sm pediatric, LA adult, LA pediatric

Answer 3

Adult k9 40-60ml/kg/day
Adul fel 50 ml/kg/day
SA ped 80-120 ml/kg/day
LA adult 40ml/kg/day
LA ped 80ml/kg/day

Question 4

What is overhydration?

Answer 4

water intoxication
caused by iatrogenic, endocrine problems (inc ADH), behavioural overconsumption
Pathological changes - inc volume in blood vessels - dec oncotic pressure + osmotic pressure in blood vessels - fluid leaves blood ves enters interstitial space - dec osmotic press in interstate space - fluid enters cells

Question 5

What are the pathological effects of overhydration?

Answer 5

ic demand on heart - inc water added to blood vessels inc BP
diuresis - inc blood flow thru kidneys inc urine
Pulmonary hypertension - fluid enters in lungs and pleural space(pulmonary edema- inc fluid in lungs)(pleural effusion - fuid in pleural space)
Cerebram edema + brain compression - ic water causes con of NA to drop, dec osmotic pressure in interstate space
cerebral edema - swelling excess fluid in brainw

Question 6

what are the clinical signs of overhydration?

Answer 6

inc HR, BP, RR, urination
dyspnea
neurological signs - headache, ataxia, tremors, central blindness, seizures, coma

Question 7

Which patients are at inc risk of overhydration?

Answer 7

heart, kidney failure
endstage liver disease
small animals

Question 8

how do you treat overhydration

Answer 8

stop any fluids, diuretics, correct any underlying endocrine condition

Question 9

what is dehydration?

Answer 9

greater water loss and intake. Neg fluid balance. reduces both circulating fluid and amount of interstitial tissue fluidwh

Question 10

What are the causes of dehydration?

Answer 10

dec fluid intake - any form of water deprivation, drinking snow
Inc losses - lactating, athletics, hot weather, hyperthermia, V/D, renal losses, iatrogenic, loss of bood/plasma

Question 11

What is oncotic pressure

Answer 11

affected by amount of soluble proteins in the blood vessels, albumin

Question 12

what is osmotic pressure

Answer 12

based on conc of electrolytes, sodium

Question 13

How can you diagnose dehydration?

Answer 13

1. history
2. CRT, MM, skin tent, HR, acute weight loss, tachycardia
3. diagnostic tests - PCV, inc total proteins

Question 14

What can you find/see with <3% hydration

Answer 14

sublinical, no PE signs, changes appear on testing (PCV, total proteins)
tx - drink more

Question 15

What can you find/see with 3%-5% dehydration?

Answer 15

Mild - often sublinical, if clinical: lethargic, MM texture, weight change, changes on testing
tx oral fluids

Question 16

what can you find/see with 5%-8% dehydration>

Answer 16

moderate - weight loss, lethargic, prolonged CRT, tacky mm, mild skin tent, clearly seen on tests
tx. iv fluids

Question 17

What can you see/find with 8%-10% dehydration

Answer 17

marked - weight loss, lethargic to depressed, prolonged CRT, tacky to dry MM, skin tent, mild tachycardia, seen on tests
tx. iv fluids and correct electrolytes

Question 18

what can you see with 10%-12% dehydration

Answer 18

severe - significant weight loss, depressed, dry MM, skin tent, suken eyes, cool extremities, tests show other changes to electrolytes and other organ func
tx. iv fluids and organ supporth

Question 19

what can you see with >12% dehydration?

Answer 19

moribund - shock and dying
tx. shot fluids, possible cpr

Question 20

How do you calculate dehydration?

Answer 20

% dehydration = (normovolemic weight in KG) - (weight when dehydrated in kg) x 100 divide by (normovolemic weight in kg)

EX. 5.47kg - 5.23 divide by 5.47 = 4.4% dehydrated

Question 21

How do you calculate deficit?

Answer 21

Deficit volume in mls = (% dehydration) x (patients weight in kg) x 1L/1kg X 1000ml/1L

1 kg = 1L

Question 22

What is the pathology associated with dehydration?

Answer 22

damage related to dec BP - dec tissue perfusion, cells/tissue less O2, nutr. delivery, dec removal of metab waste products
Kidneys + intestinal mucosa affected first (kidneys receive most blood flow)
Changes in electrolyte conc - hypernatremia - inc NA conc causes body water to shift compartments
metab acidosis