Acid/Base/Fluid/Lyte Flashcards
Free water deficit calculation?
TBW x (serum Na / normal serum - 1)
Normal SID in dogs vs cats
dog: 27 mEq/L cat: 30 mEq/L
What toxins cause type B lactic acidosis?
cyanide ethanol ethylene glycol
For every 100 mg increase in glucose, sodium decreases by?
1.6 (pseudohyponatremia)
Myelinolysis lesions in dogs vs people?
dog: thalamus people: pons (hence “central pontine myelinolysis”)
Boag, JVIM, 2005. Dogs with linear FBs were more likely to have what e-lyte abnormality?
Hyponatremia. Study also found hypochloremic metabolic alkalosis found in most regardless of GI or jejunal FB. 25% hypokalemic
death and severe complications of hyponatremia typically occur when the serum Na concentration is less than what?
120 meq/L
what gradient of water between the plasma and brain in dogs can result in translocation of water between plasma and the brain in dogs?
30-35 mOsm/kg gradient
when hyponatremia is chronic, brain volume is adjusted toward normal via what mechanisms?
loss of potassium and organic osmolytes from cells
what are the clinical signs of acute water intoxication?
weakness, incoordination, and seizures
T/F- acute water intoxication likely occurs only if the patient has an underlying cause of impaired water excretion at the time of water load?
true
severe symptomatic hyponatremia of acute onset (clinical signs)
death, cerebral edema, seizures
what is the maximum recommended rate of correction of chronic hyponatremia?
>10-12 meq/L in 24 hrs
name the type of injury that occurs to the brain when chronic hyponatremia is corrected too quickly
demyelination or myelinolysis
where in the brain are lesions often found with demyelination from sodium correction?
pons, thalamus, subcortical white matter, cerebellum
list the MRI abnormalities associated with demyelination
hyperintense area on T2, hypointense on T1, not enhanced with contrast
list the clinical signs that have been reported & associated with myelinolysis?
lethargy, weakness, ataxia, progressing to hypermetria and quadriparesis, loss of CPs, dysphagia, trismus, decreased menace
What mechanism causes a hyponatremic patient to excrete solute-free water via the kidneys when they are volume resuscitated?
volume repletion in hypovolemic patients abolishes the nonosmotic stimulus for vasopressin release and allows the animal to excrete solute-free water via the kidneys- this itself tends to correct hyponatremia
in edematous hyponatremic patients, what treatments should be considered?
dietary sodium restriction, diuretic therapy or 0.9% NaCl in combination with a diuretic for rapid correction of hyponatremia
How do AVP receptor antagonists work?
block either V2 or V1/V2 receptors and increase free water excretion by the kidneys; they normalize serum Na in patients with non-osmotic release of AVP causing euvolemic (SIADH) or hypervolemic (CHF, liver failure) hyponatremia
Why are infusion site reactions common with administration of conivaptan, a V2/V1A receptor antagonist?
the pH of the drug is very low
T/F- vasopressin Rc antagonists have been shown to improve survival in patients with CHF?
false, but they do promote aquaresis and correct hyponatremia in this population
Which other drugs should be cautiously administered when giving conivaptan?
other CYP450 inhibitors such as ketoconazole
what is normal water intake for dogs? cats?
dogs- 90 ml/kg/day cats- 45 ml/kg/day