Fluid Therapy Flashcards
Indications for fluid therapy
Decreased intake dehydration decreased circulating volume (shock) need for overhydration correct electrolyte abnormalities
What clinical indicators are used to indicate need for fluid therapy
skin turgor (changes at 8-10%) - neck in adults, eyelid in foals or geriatric
MM - moisture level and CRT
urine production - decreased unless renal disease
sunken eyes - rare in horse
depression, muscle weakness
heart rate - tachycardia = one of first things you’ll see
decreased jugular distensibility
What lab indicators are used to indicate need for fluid therapy?
PCV - splenocontraction can over or underestimate degree dehydration
TP - increase
BUN/Cr
Albumin - need to keep above 1.5g/dL, only cause of hyperalbuminemia is dehydration
lactate
urinalysis - typically USG of >1.030
PCV increase iwith dehydration
for every 2-3% increase in % dehydration over 5%, PCV increases 5%
5% dehydration
skin tent: 1-3s MM - moist to slightly tacky CRT - normal, <2s HR - normal Other: decreased urinary output
8% dehydration
skin tent: 3-5s MM - tacky CRT - variable (2-3s) HR - 40-60bpm other: decreased arterial blood pressure
10-12% dehydration
skin tent: 5 or more s MM - dry CRT - variable, often >4s HR - >60bpm other: reduced jugular fill, barely detectable peripheral pulse, sunken eyes
15% dehydration
death imminent
oral fluids
animals drink at own will
- never place electrolyte solution alone, always with access to free water
nasogastrically intubated - can leave in for short time to avoid repeated trauma, can give 6-8L = 12-16L/h (30m transit to stomach)
A: most physiologic, non-invasive, not expensive, can loosen impactions in LI
D: DON’T GIVE IF ILEUS, GASTRIC DISTENTION OR REFLUX
IV fluids
place catheter so fluids flow towards the heart
typically 14G 5.5” Angiocath
A: easy access, allows easy change in fluid plan, almost unlimited available amount of fluids and rate
D: danger of compromise to vein, sepsis risk, sterility, cost, requires monitoring
jugular vein
easy access, well tolerated, catheter inserted downwards
Lateral thoracic vein
second choice, esp if dysfunction of one jugular v
catheter placed horizontal to gravity, towards head
poor choice for recumbent animal
Cephalic vein
first choice for limb catheters, placed tip towards heart,
disadvantages: easily clots due to placement against gravity, advised to always have fluids running through, not used for medication administration alone
Saphenous vein
easily bent due to limb motion, placement MUCH less tolerated, typically only used if “running out’ of veins
Subcutaneous fluid administration
helpful in foal but rarely used, not used in skin
no clinical indications for use
Intraperitoneal fluid administration
A: can get large volumes in at rapid rate, easy access, could be alternative if limited venous access
D: vigilant monitoring needed, sepsis is risk, except to get large volumes but practically cannot because fluid tracks down within abdomen
Rectal fluid administration
use gravity flow or pump, have horse standing on an incline with head lower than hind limbs
A: no sterility required, absorption across gastric mucosa, potentially large fluid volumes, helpful if limited venous access
D: can’t help in moderate to severe ileus, cannot be used in severe colitis
Intraosseus fluid administration
used in severe dehydration to increase circulatory volume if no jug filling, esp foals
D: difficult, strict sterility, limited rate of administration due to needle size
Intracecal fluid administration
A: large volumes directly into intestinal segment with greatest absorption
D: more invasive, strict sepsis
Rate of flow through system dependent on:
radius/diameter of catheter
pressure differences (change in fluid height - rate can increase if you raise fluid higher)
length of system components - longer = slower rate
viscosity of fluid
STAT IV flow rates
14G - 5.25” - 13.1L/hr
12G - 26.9L/hr
10G - 36.5L/hr
Typical STAT IV equine set up
8’ above horse head, 28L/hr gravity flow capacity
12 drops/ml
Long term vs short term catheters
Long term: up to 14d, soft material, over wire placement, expensive, polyurethane or silicone
Short term: up to 72h, teflon and polyethylene
catheter complications
thrombosis, cracking, breakage, air embolism, extravasation
Rate of thrombosis dependent on
systemic state (coagulation status) of animal
stiffness of catheter - more stiff more thrombogenic
size of catheter - larger more thrombogenic
length of catheter - more thrombogenic
material - polypropylene = most thrombogenic, polyurethane (mila) = least thrombogenic
vessel trauma