Flash Notes Miscellaneous - Fluid Therapy Flashcards
what is osmolarity? what is osmolality?
osmolarity: number of particles/liter of solution ~ total concentration of a solution or fluid environment measured in milliosmoles/liter, osmolality: same but measured in milliosmoles/kg
what is tonicity?
effect of a solution/fluid environment has on cell colume, so fluid moves in response to the concentration gradient created by the surrounding environment limited by the permeability of the cell membrane - effective osmolarity of the surrounding fluid/environment on cell volume
what is isotonic? hypotonic? hypertonic?
isotonic: no change, hypotonic: increase in volume, so cells swell, & hypertonic: volume decreases, so cell shrinks
what is hypovolemia?
ineffective circulating blood volume, absolute hypovolemia: actual loss of fluid out of the vascular space, relative hypovolemia: usually caused by vasodilation such that circulating volume is inadequate (seen with severe inflammatory conditions like anaphylaxis/sepsis)
what are replacement fluids?
fluids used to replace deficits (similar to plasma) given as bolus or continuous infusion
what are maintenance fluids?
fluids used for daily requirements, so lower levels of sodium/chloride than plasma but higher levels of calcium, potassium, and magnesium provided alongside water/calories - patients are switched to theses once intial deficit is corrected, so continuous infusion only NO BOLUS due to risk of edema
what are resuscitation fluids?
correction of life-threatening hypovolemia - fluid therapy for patients with extreme loss
what are crystalloid fluids?
solutions with electrolytes/other substances that are able to cross into all fluid compartments of the body, mainstay of resuscitation & all types of fluid therapy (normal or 0.9% saline, dextrose solutions, LRS, normosol, plasmalyte) hypertonic crystalloids: concentrations of saline greater than 0.9%, 7% hypertonic saline most commonly used in vet med
what are balanced solutions?
constituents & concentrations resemble content & osmolality of normal extracellular fluid (LRS, 0.9% saline, & 5% dextrose)
what are colloids?
molecules of high molecular weight usually proteins or carbs that are not readily able to cross cell membranes & therefore remain in the vascular space for longer durations (hetastarch, dextrans, plasma, albumin)
what is COP?
colloid osmotic pressure, pressure created by the presence of colloids in a solution that prevents movement of fluid across a semi-permeable membrane
what are the 2 most common colloids used in vet medicine?
6% hetastarch % 6% dextran
what changes will affect fluid flow across a capillary membrane in a patient resulting in an increased net flow into the interstitium causing edema?
increase in blood pressure, decrease in tissue COP, or increase in permeability
what is the fluid portion of the body? how is it split up?
60% of total body weight, 2/3 is intracellular fluid & 1/3 is extracellular fluid (4% plasma & 15% interstitial)
T/F: total body fluid is 60% of the total body weight
TRUE
total body water & ECF compartments are larger in what animals?
neonates - 70% TBW & 30% ECF
intravascular fluid loss is reflected by changes in what?
changes in cardiovascular system - heart rate, pulse strength, CRT, mucus membrane color, & body temperature
loss of fluids from the interstitium & intracellular areas are apparent from what clinical signs?
clinical signs of dehydration - loss of skin turgor, dryness of mucus membranes, & sunken eyes
what are the 2 questions you must start with for identification & need for treatment using fluids?
is there a fluid deficit & what fluids should be used for replacement
what lab values increase with fluid loss? what about with hypovolemia? what factors may obscure the clinical picture?
increase: PCV, total solids, total protein, USG, & albumin, hypovolemia: lactate & hypotension when severe - hemorrhage or protein loss may obscure the lab picture
T/F: in young calves with diarrhea, clinical signs correlate with dehydration & metabolic acidosis
TRUE
T/F: calves have loss of fluid & loss of HCO3 that may be severe
TRUE
hypovolemia results in a switch to what metabolism? what is seen with that?
switch to anaerobic metabolism - increased lactate & lactic acidosis
what clinical signs are seen in small animals with 5-6% dehydration in regards to skin tenting, mucus membranes, CRT, & signs of shock (increased heart rate, weak pulses, & cool extremities)?
may see skin tenting, mucus membranes likely ok, potentially increased, not likely to see signs of shock
what clinical signs are seen in small animals with 6-8% dehydration in regards to skin tenting, mucus membranes, CRT, & signs of shock (increased heart rate, weak pulses, & cool extremities)?
slow return of skin tent, mucus membranes may be dry, mild increase in CRT, less likley to see signs of shock
what clinical signs are seen in small animals with 10-12% dehydration in regards to skin tenting, mucus membranes, CRT, & signs of shock (increased heart rate, weak pulses, & cool extremities)?
very slow return of skin tent, dry mucus membranes, increased CRT, & may see signs of shock
what clinical signs are seen in small animals with 12-15% dehydration in regards to skin tenting, mucus membranes, CRT, & signs of shock (increased heart rate, weak pulses, & cool extremities)?
skin may not retract, very dry mucus membranes, very increased CRT, & signs of shock present
how does body condition affect skin tenting in small animals?
increased tenting of skin if thin, decreased skin tenting if fat
how is base deficit determined in a calf under 8 days old that has a base deficit of 0?
alert, good suckling reflex, standing/still standing but depressed
how is base deficit determined in a calf over 8 days old that has a base deficit of -5?
still standing but depressed
how is base deficit determined in a calf over 8 days old that has a base deficit of -10?
sternal & more depressed
how is base deficit determined in a calf over 8 days old that has a base deficit of -15?
no suckle & moderate dehydration
how is base deficit determined in a calf over 8 days old that has a base deficit of -20?
no suckle & severe dehydration
how is base deficit determined in a calf under 8 days old that has a base deficit of -5?
weak suckle & slight dehydration
how is base deficit determined in a calf under 8 days old that has a base deficit of -10?
no suckle & moderate dehydration
how is base deficit determined in a calf under 8 days old that has a base deficit of -15?
lateral & extreme depression
what calculation is used to determine fluid need in large animals?
horses/cows 50ml/kg/day, 100ml/kg/day in neonates
what calculation is used to determine fluid need in small animals?
40-60ml/kg/day; [(BW(kg)X30) + 70] or, if under 2 kg or greater than 50 kg, use BW^0.75 X 70
what are some examples of how animals can lose fluids?
gastric reflux in horses, effusions in FIP, & cows with choke with excessive salivation
what are some pathways for fluid deficits to occur? why is this important to consider?
lake of intake, hemorrhage, urine loss with polyuria, respiratory (excessive panting), salivation, skin (burns, severe wounds), inflammation, & intestines - NEED TO KNOW TO DECIDE WHAT REPLACEMENT FLUIDS TO USE
what fluids can calcium not be mixed with?
bicarbonate & LRS
what animals may need dextrose added to their fluids?
hypoglycemia patients, neonates, toy breed dogs, & liver disease patients
what animals may need bicarbonate added to their fluids?
calves with diarrhea - NOT FOR LACTIC ACIDOSIS
what is kmax for potassium additives in fluids?
0.5mEq/kg/hr - enteral intake is best to correct potassium deficits
what is the most important extracellular ion? what about most important intracellular ion?
extracellular: Na, intracellular: K+
what does chloride do in acidosis? with vomiting? with abomasal obstruction?
in acidosis: will increase, vomiting: lost woth vomiting, & abomasal obstruction: very low
what must also be corrected with a low calcium or low potassium?
must correct low magnesium!!!
how are enteral fluids used?
very useful - always use if available, voluntary intake/force feeding - or feeding tubes
when should subcutaneous administration of fluids be used for fluid therapy?
small animals or any species with loose skin, patients with mild deficits without signs of shock, & supplementation if not drinking well yet/with chronic disease (chronic renal failure cat)
when should intravenous administration of fluids be used for fluid therapy?
any species with accessible veins (jug, cephalic, & saph most common), vital for resuscitation of severe deficits
when should intraosseous administration of fluids be used for fluid therapy?
small animals/birds/reptiles/foals/neonates in very dehydrated patients or difficult to catheterize - volume & speed similar to IV
when should intraperitoneal administration of fluids be used for fluid therapy?
primarily done in small lab animals - enterocentesis is a concern
why do you want a large bore catheter for a hypovolemic animal?
faster flow of fluids - catheter must be smaller than vein to decrease phlebitis
what are the shock doses used for fluid therapy?
80ml/kg for dogs, 50ml/kg for cats, & 8% body weight for horses/cows
what determines how fluid moves passively between the different areas of fluids?
concentration gradients of large molecules (COP), sodium, & in response to hydrostatic pressure (capillary blood pressure or tissue pressure)
what is a shock fluid dose?
shock dose ~ blood volume
