Exam 1: Approach to Fluid Therapy in Companion Exotics

describe the compensatory phase

• blood pressure increase

• blood loss <20%

• increased heartrate, increased to normal BP and CRT

• fluid replacement therapy

describe early decompensatory phase

• fluid losses continue >25-30% blood volume

• hypothermia, increased heart rate, depression, decreased to normal blood pressure

• aggressive fluid replacement therapy

describe decompensatory phase

• blood loss >60%

• obtunded patient

• weak to no pulse

• severely decreased heart rate

what is perfusion

transport of fluid and O2 through vessels to capillaries

how is adequate perfusion described

• adequate intravascular volume

• proper function of cardiovascuar system

what are the goals of fluid therapy

• administer the least amount of fluids needed by the patient

• restore perfusion and hydration without volume overload

• have a treatment goal

• assess clinical response towards treatment goal

• early intervention

what are methods of fluid administration

• bolus= IV, IO, subQ

• continuous = IO, IV

how are crystalloids generally described

• LRS, Saline, dextrose, LRS +2.5% dextrose

• indicated in severe hypoperfuse dehydrated patients

• must be kept warm 105F

• bolus up to 20mL/kg IV or IO over 5 minutes every 4 hrs

why are fluids continiously administered to birds

only 20% of fluids administered remain in vascular compartment 1 hr after it enters the bloodstream

how is metabolic acidosis caused by shock corrected

• LRS (lactate = bicarb), increase extracellular fluid pH

• correct perfusion and hydration status

• severe acidemia confirmed at pH <7.10 and HCO3 <8

• dose sodium bicarb NO MORE than 1-2mEq/kg over 30 min, monitor blood gases

how is LRS described in exotics

• supplemented with potassium chloride (0.1-0.3 mEq/kg to a max dose of 11/day)

• plasma potassium and sodium levels are low (vomiting, diarrhea)

describe colloidal fluids

• synthetic such as hetastarch, plasma, dextran

• biologic such as whole blood, plas,a, albumin

• indicated in acute hemorrhage, head injuries, pulmonary trauma, myocardial dysfunction, hypoalbuminemia

• bolus of fluids up to 10-15mL/kg IV or IO over 10 min q8hrs up to 4 times

what is the goal of plasma, dextrans, and hetastarch if they do not cross the vascular endothelium?

• replace lost protein

• help to maintain plasma oncotic pressure

• reestablish circulatory volume

what is the exact function of hetastarch

negative charge attracts Na and H2O, expands volume of intravascular space by 1.4x the volume infused

what are the benefits of colloids in exotic species

• decreases crystalloid fluid administration down to 40-60%

• most patients accomodate acute hemodilution of the hematocrit up to 20%

• most appear to be safe in companion exotics

why must caution be taken when using synthetic colloids in exotics

• excreted renally → congestive heart failure, anuric/oliguric renal failure

how can you limit side effects of using synthetic colloids in exotics

• hemostarch dose 10-15ml/kg IV for 1-4 treatments over 24 hrs

• reduce the volume of crystalloid administration by the volume of hetastarch used to prevent fluid overload

how are critical patients assessed and stabilized

• place in warm incubator

• oxygen supplementation PRN

• most pt given warmed crystallod fluids 3ml/100g bw

• once stabilized, dx and tx for dehydration and hypovolemia, BP, glucocorticoids

describe bolus administration of fluids to hypovolemic exotics upon stabilization

• crystalloids 10mg/kg and colloids 5mg/kg until clinical response

  • usually 1-2 bolus treatments required

wha is the formula for fluid deficits

estimated dehydration (%) x body weight (g) = deficit (ml), + maintenance 4mL/kg/hr

how should maintinence fluids be given to exotics

• provided until pt is fully hydrated and drinking water to maintain

• IO and IV should be used

• SubQ preferred for birds due to reluctance to maintain indwelling

• shock pt cannot take subq

• subq no more than 10mL/kg/site

• use isotonic

what osmolarity of fluid is reccomended for parrots

300-320

what is plasma osmolality

• number of particles in a solute, disregarding size, weight and charge

unit for osmolality

mOsm/kg- weight

unit for osmolarity

mOsm/L- volume

what is the difference in osmolality and osmolarity of body fluids

non substantial difference

what is determined by relative osmolality of intracellular and extracellular spaces

fluid volume in each compartment

what is the mammalian response

• primary mechanism for controlling osmolality

• response to increase in plasma osmolality → release of vasopressin

what is the osmolarity of most prepackaged fluids

308 mOsm/L

give overall means for plasma osmolality for different parrots

• amazon parrots 326.0

• african grey 305.8

• red fronted macaws 299.8

decreased plasma osmolality = ?

shift from extracellular to intracellular spaces

increased plasma osmolality = ?

shift from intracellular to extracellular space, cellular dehydration

what are the consequences of large dosages of LRS

decrease in plasma osmolality, intracranial swelling

what are the best products for avian fluid replacement

• normosol-R

• plasmalyte-R

• Plasmalyte-A

• NaCl 0.9%

what is the recipe for fluids with higher osmolarity

500mL of 310mOsm/L fluid + 490 mL of normosol-R + 10mL of 3% NaCl

how is dehydration determined in birds

• skinfold elasticity

• corneal moisture

• appearance of the globe

• packed cell volume

most critically ill birds are ?

• hypoperfused-dehydrated

• Iv or IO in critcal cases

• SC or PO in non- critical cases

what is the expected dehydration status of severe trauma or disease

5-10%

how should fluid administration be spread out?

first 12-24hrs give 50% deficit + maintenance; remaining deficit and maintenance over next 2 days

where are IV catheters placed in birds

• basilic/ulnar

• medial metatarsal

  • jugular

where to place IO catheters

Ulna, tibia, femur in chicks

how is giving subq fluids described in birds

• not an effective method of rapid restoration of circulatory fluid volume

  • adding hyaluornidase increases absorption rate

what are the maintenace requirements of reptles

20-30 mL/kg q24-48hrs
shock= 5mg/kg IV bolus

what is the issue with rehydrating reptiles

hard to give fluids beyond maintenance without over hydrating

how are crystalloids used in reptiles

• same as mammals

• monitor PCR and TS/TP closely with long term therapy to prevent overhydration

  • remember the effect of temperature

how is reptile Iv access described

• preferred critical cases, difficult hypotensive cases and small patients

  • cephalic and jugular preferred

describe reptile jugular vein catheterization

• cut down procedure that requires analgesia/anesthesia

• approximately 9 scales cranial to heart in snakes

• blunt dissection

  • 22-25ga cath

describe IO access in reptiles

• proximal tibia in lizards

• bridge of shell

• advantages - collapse of peripheral vessels, rigid and stable

  • limited by volume of administration

how is subq fluid described in reptiles

• limited SQ space in some species

• lower skin elasticity

• use butterfly catheter

what equipment is used for oral fluid administration in reptiles

• lubricant- prevent aspiration

• speculum/mouth gag

• tubes (stainless steel, red rubber)