Fluid Therapy Flashcards
What are the indications for fluid therapy?
Decreased intake Dehydration Shock Need for overhydration Improve perfusion Correct electrolyte abnormalities
What are the types of shock ?
Hypovolemic- hemorrhage, endotoxemia, sequesteration
Vasculogenic- endotoxemia, drainage of thorax
Maldistributive- sepsis, endotoxemia
Cardiogenic - rare in horse
In what cases would there be a need for overhydration??
Liquefaction of respiratory secretions to help expectoration
Intestinal impaction —> increased flow of fluids in lumen of intestine
You can see increased skin tenting at what percent of dehydration ?
8-10%
Tachy mucus membranes can be seen at what percent dehydration?
5-7%
What is the primary sign that an animal is dehydrated?
Decreased urine output
- will have increase USG unless there is renal involvement
T/F: CRT is the best indicator of dehydration
False
Skin tent and mm hydration are better indicators
CRT indicates perfusion (hypovolemia)
Sunken eyes in a horse indicate what degree of dehydration
12-15%
Horses only have sunken eyes in SEVERE dehydration -> imminent death is possible
T/F: sunken eyes in ruminants can be seen at 8-10% dehydration
True
What do you expect heart rate to be in a dehydrated patient?
Expect tachycardia
Can be an indicator of developing dehydration but can have many other causes
_________ can give overestimated impression of dehydration or can cause anemia to be underestimated
Spleenocontraction
For every 2-3% increase in percent dehydration greater than 5% dehydration, the PCV will increase ____%
5%
If your horse has a baseline PCV of 36%, and the horse is 7% dehydrated, what is the expected PCV?
7% - 5% dehydration = 2%
2% correlates with a 5% increase in PCV
36 + 5 = 41%
What is the only possible cause of hyperalbuminmeia?
Dehydration
What are clinical signs associated with hypovolemic shock?
Prolonged CRT (poor perfusion) Decreased jugular filling Tachycardia Decreased pulse pressures Cold extremities Decreased skin turgor
What are the major limitations of fluid administration via SQ?
Can’t get enough fluid in this space to make a difference in the adult horse
Rarely used in foal
What are the two most common methods of fluid administration in the horse?
PO
IV
What are the advantages to using PO administration of fluids?
Most physiologic
Inexpensive, non invasive
Especially helpful with LI impaction and overhydration techniques
What are the disadvantages of PO administration of fluid?
Contraindicated in gastric distention, reflux, and ileus
What are the locations for IV fluid administration in horse?
Jugular
Lateral thoracic - not in recumbent animals (dislodged)
Cephalic vein - easily plugs due to effect of gravity
Saphenous- typically only placed in severely depressed horses “running out” of veins to be accessed
What are the advantages to IV administration of fluids?
Easy access
Can give almost unlimited fluid
Easy adjustment of fluid plane
Disadvantages to IV fluid administration?
Vein compromise -> thrombosis, thrombophlebitis, septic, phlebitis
Introduction of organisms (sepsis)
Requires aspetic technique
When giving intra-peritoneal fluids, where do you administer?
Left flank.. less GI stuffs on this side
What is the major disadvantage of intra peritoneal fluid admin?
Tends to tract down with abdomen causing space occupying lesion in abdomen resulting in abdominal discomfort (colic from injury or fluids?)
What are the advantages of rectal fluid admin?
Allow GIT absorption
Can be used in severe dehydration to increased fluid if there is no jugular filling
Can admin large volumes
When would fluids administered rectally be contraindicated ?
Severe ileus
Severe colitis
What is the main limitation of intraosseus fluid admin in horses?
Fluid rate limited by max needle size
2L/hr- can be useful in foals but the adult maintenance is usually more than this
What are the advantages and disadvantages of intra-cecal fluid administration?
Advantage - fluid into GIT with most capacity for absorption
Disadvantages - invasive, can lead to peritonitis/sepsis
What is the most important factor in flow rate?
Radius of catheter
What is the flow rate through a 14G 5.25” catheter
13.1 L/hr
What is the flow rate through a 14G 3.25” catheter?
14.9 L/hr
What is the flow rate through a 12G catheter?
26.9 L/hr
What is the flow rate through a 10G catheter?
36.5 L/hr
What is the flow rate for a STAT IV at 8’ above the horse?
28L/hr
When using a STAT IV set at standard 8’ ceiling, which of the following catheters will the STAT IV be the limiting factor for flow?
A. 14G (5.25”)
B. 14G (3.25”)
C. 12G
D. 10G
10G (by itself has a flow rate of 36.5L/hr)
StatIV has max flow rate of 28L/hr
How long can polyurethane/silicone catheters stay?
Long term (up to 14days)
Teflon and polyethylene catheters can be left in how long?
Short term (max 72hrs)
What are complications due to catheters?
Thrombosis Cracking Breakage Air embolism Extravasation (perivascular leakage)
Septic phlebitis
Abscessation
Neurological dysfuntion
Sloughing
What is the rate of thrombosis dependent on??
Systemic state (coagulation status): esp in state of endothelial and sepsis
Stiffness, size, and length of catheter (stiff, long, and large =thrombosis)
Material: polypropylene > polyethylene > teflon > silicon > nylon > polyurethane
What are the consequences to extravasation with catheters?
Local inflammation and pain
Secondarily leads to phlebitis and thrombophlebitis
T/F: Selection of appropriate fluid is dependent on expected/documented losses in the individual patient
True
What is the typical acid/base disturbance in a horse?
Metabolic acidosis
What type of solution has decreased tonicity compared to plasma?
Hypotonic solution (eg half strength saline - 0.45%)
What are commonly used isotonic solutions?
LRS
0.9% NaCl
Normosol
D5W
What type of solution has tonicity above plasma?
Hypertonic (7.2% NaCl)
Indications for using hypertonic saline??
Most strongly: emergency resuscitation in hypovolemia (hemorrhagic shock)
Burn patients
Acute trauma
Acute neurologic trauma
What is the MOA of hypertonic saline?
Fluids shift from intracellular space (or 3rd space) into ECF space
Trigger central brain receptor mechanism -> stimulates CNS response favoring CV stability
What are the effects of hypertonic saline?
Improve CO, MABP, urine production, with decrease in systemic vascular resistance.
- > increase preload
- > decrease afterload be decreasing endothelial cell swelling
What are the adverse reactions that can occur when giving horses hypertonic saline?
Hemolysis
->free hemoglobin
Cardiovascular alterations
-> arrhythmias
->ventricular premature contractions (VPC)
With 25% HS/25% Dextran
(Hypertonic first pass to the heart —> neg ionotropic)
Hypertonic saline decays rapidly. What can be added to prolong its effect?
6% Dextran 70
When is hypertonic saline contraindicated ?
Uncontrolled hemorrhage
—> increased MABP and CO causes increased bleeding and CV collapse
Severe hypernatremia (seizure) Severe hypokalemia (promote more loss when renal fxn is restored)
