Clin Med - Equine FT

drraythe's version from 2016-03-14 18:25

Equine Fluid Therapy (There are cases+answers in another PPT, be sure to check that out!!)

Question Answer
What are some reasons a horse would have a lack of water intake?Frozen / blocked water source, Systemic Dz or specific Dz
What are some reasons a horse would have Excessive loss of water (& electrolytes)?Diarrhea / gastric reflux / sweating, etc.
When would be some situations where a horse would have an Excessive intake of electrolytes?Salt intoxication (they love their salt lick too much) / Incorrect mixing of milk replacers
(Not sure how important this slide is) How much does an average adult horse weigh? How does this translate into how much water is in their body & where?Avg adult horse= 500kg. 60% of the horse is water, so 300L. Then ICF is 40% of BW so ICF= 200L & ECF is 20% of BW, so 100L (of ECF being 100L, interstitial is about 75L & plasma is about 25L)
How much does the average horse neonate weigh? How much of their body weight is water?About 50kg for a neonate horse, their body is 75-80% water (adult is 60)
What is a neonate's USG like compared to an adult's USG & why might it be this way?The USG is MUCH LOWER (1st off, they are just made of more water to begin w/) which means 1.003-1.008 is normal (adult's is usually around 1.025). This also has a lot to do w/ the fact that they are on a milk diet & Na+ is LOW in mare's milk
What is the normal daily fluid requirements of an adult horse?Adult Horses: 50ml / kg / day
_________ + ___ losses = maintenance (Fill in the blanks). What are some things that cz a horse to lose water on a daily basis?Sensible+insensible losses= maintenance. There is fecal water loss, renal water loss & Evaporation from skin + respiratory tract
Describe what a horse's water consumption is likeThey do peri-prandial drinking! Which means their Water consumption depends on diet
Volume depletion refers to a reduction in _________ volumeECF
What are examples of things that lead to loss of isotonic body fluid?Blood loss / diarrhea / gastric reflux
Explain hypovolemia vs dehydration in terms of what is being lostHypovolemia= loss of circulatory (blood) volume
Dehydration= excessive loss of total body water
What are the CS of dehydration? Hypovolemia?Dehydration is Tacky oral mm, skin tent (not always super accurate, bc old skin loses elasticity) & sunken eyes (ONLY USEFUL IN FOALS, not sensitive in adult horses). HYPOVOLEMIA, on the other hand, is more severe & signs also incld: ↑ HR, ↑ RR, ↓ pulse pressure, ↓ jugular fill, cold extremities & ↓ urine output (which means ↑ USG)
What are the 3 lab Parameters you can try to look at to evaluate dehydration? Explain how each 1 relates/how useful it is(1) PCV/TP (not sensitive or specific)
(2) Lactate (product of anaerobic metabolism)
(3) Creatinine / BUN
What are the 2 ways you can measure volume status? What should you know about each method?(1) Central Venous Pressure... however, this is Affected by head position (CFR jugular pulse)
(2) Mean Arterial Pressure (measure w/ tail cuff)
What is normal central venous pressure in adult horses?7-12 mm HG is normal in adults
IV route of fluid admin is essential for what?Resuscitation
PO route of fluid admin is only used when?Only when GI tract is normal
Intra peritoneal route of fluid often is this used in horses?Rare in horses
Subcutaneous route of fluid often is this used in horses?Rare in horses
What is the 1° site of catheter placement in horses? What is the 2° place & why would you use the 2° place? & another auxiliary place?1° is the jugular vein.
2° is the cephalic vein, which would be the next option when there is a jugular vein thrombus.
The lateral thoracic vein is another good option.
What kinda bore do you want on your catheter if you're using it in a horse?A LARGE bore (bore= hole in needle)
What are the 3 types of catheters she mentioned? Explain when they'd be used(1) Over the needle (good for short term use)
(2) Over the wire (good for long term use, it is very supple & non-thrombogenic)
(3) Through the needle (for peel-off systems)
Chart on slide 16-she said we shouldn't freak out about it too much, but still look over itTypes of catheters & their pros & cons
What are the 2 major complications of IV fluid therapy in horses?Thrombophlebitis & over hydration in neonates/foals
Is a hypertonic saline solution (HSS) a crystalloid or colloid?Crystalloid
Isotonic = ____ solutionPolyionic solution
How do you calculate how much fluid a dehydrated PTx needs?Liters of water ‘lost’ = B.W. in kg x estimated % of dehydration
What are the 4 overlapping phases of a fluid therapy plan? (If time relevant, give the time)(1) Resuscitation (<2hrs) ← emergency!
(2) Rehydration (12-24 hours)
(3) Maintenance
(4) Ongoing losses
**What is the rate for resuscitation that she said we should keep in our heads?50ml per kg per day
What is the shock dose of fluids for a horse? How does this relate to body weight/blood volume? What is something to keep in mind about this, clinically?50-80ml/kg. This is about ~8% of body weight, aka about 1 blood volume. (That means for a 500 kg horse, it would be about 40L! So this isn't always clinically practical) (so start by giving 1/4 of dose as bolus, reeval, etc)
Hypertonic Saline Solution (HSS) → how much of the solution is sodium chloride? How many osmols per liter does it provide?7% Sodium Chloride, 1200mEq Na + 1200mEq Cl = 2400Osmol/L
Hypertonic Saline Solution (HSS) → What is the amount of bolus you'd want to give for HSS? What is the effect on the blood volume/ body?2-4 ml/kg bolus (1-2L per 500kg). This czs an immediate vascular expansion at about 2-3xs the amount infused. It alters the ECF & leads to a shift in the ICF
***If you are giving HSS (hypertonic saline solution) what else MUST YOU DO? (Incld #s)Every 1L HSS needs replacement w/ 10L isotonic fluid!!!!!!
What is the natural colloid for horses? What are the 2 synthetic colloids?Equine plasma is the natural colloid. Hetastarch & Pentastarch are the 2 synthetic colloids.
What are some benefits to using colloid fluids? When is it especially useful?Contain large molecules that remain in the vascular space, Plug capillary endothelium, Improve plasma oncotic pressure, Useful in cases w/ hypoproteinemia
When is Rehydration the 1st step? Why must you still do rehydration after Resuscitation?Rehydration is the 1st step in mild cases of fluid deficits. The reason that we must perform rehydration after Resuscitation is bc Resuscitation may not correct whole deficit & rehydration accounts for Loss of vascular volume & total body water
How much is the minimum amount of dehydration reqd for CS to appear?5%
Equation to determine how many L have been lost/ are needed?Amount (L) = % dehydration X body weight (kg)
How fast must administration take place in resuscitation? Rehydration?Resuscitation must happen in <2hours, Rehydration can occur over 12-24 hours
Which routes of admin can be used in resuscitation? Rehydration?Resuscitation must be IV. Rehydration can be IV OR enteral (if GI tract is healthy)
What type of fluids would you want to use in rehydration? Why?Isotonic crystalloids, bc they replace fluids & Correct electrolyte imbalance
***WHAT IS MAINTENANCE RATE???50 ml / kg / day → So, 1 liter/hr maintenance (500kg horse)
Maintenance → When would you want to supplement electrolytes?If there is an existing deficit / or if on fluids > 24 hours
Maintenance → What kind of fluids should you use → what would you base this decision off of? What if you didn't have these tools?Base decision on actual measurement of electrolytes & blood gases...if no lab, choose balanced polyionic
What are the 2 important electrolytes she mentioned?Ca & K
Calcium → how much is usually in fluids? Per L?Ca is usually added in 5L bags, 25ml 23% calcium-gluconate / liter
Potassium → When would you want to give K to a horse? How much would you give per L? Cautions?You would give K to horses w/ hypokalemia or on IV fluids > 24h & you'd add 10-40mEq / liter. CAUTION!!: K+ must be <0.5 mEq/kg/hour
What are some factors which the rate of fluid administration is dependent on?PTx (adult horse or foal), Severity of underlying deficit, Ongoing losses, Type of fluid administered (Crystalloid / Plasma / Blood products), Route of administration (enteral vs IV)
Ongoing losses → these are usually difficult to estimate. What must you do to try to figure these out? How would you administer for ongoing losses, in general? How would you monitor?You will have to try to compare the "ins & outs" of the horse (drinking, peeing, etc). You typically replace by higher maint. Requirements. Lastly, you can monitor response to therapy by looking at CS & laboratory Parameters