Fluid Therapy

A patient with mild tachycardia, tacky mucous membranes, and increased CRT is most likely suffering from simple dehydration or volume depletion?

simple dehydration

A patient with normal jugular vein fill and peripheral pulse pressure is consistent with volume depletion. True or False?

FALSE - these findings are more consistent with simple dehydration (or a normal animal)

A patient with prolonged jugular vein fill and reduced peripheral pulse pressure is most likely simply dehydrated or volume depleted?

volume depleted

What other terms are interchangeable with volume depleted?

decreased effective circulating volume and hypovolumic

How might the extremity's temperature be affected if the animal is simply dehydrated? what if volume depleted?

if they are simply dehydrated - extremity temp may be WNL or cool, if they are volume depleted temp may be cool to cold

How would mentation differ between a patient that is simply dehydrated vs. one that is volume depleted?

mentation for a dehydrated patient may be BAR/QAR, whereas a volume depleted animal would most likely be obtunded

What circumstances require a need for resuscitation with fluid therapy?

signs of decreased effective circulating volume (volume depletion) - there has been a loss of body water and electrolytes

Where does fluid need to be replaced in the case of resuscitation?

the ECF

What form of fluid administration is typically utilized for resuscitation?

IV fluids!

What is the shock dose of IV fluids?

80-90 ml/kg

What circumstances require a need for rehydration with fluid therapy?

clinical signs first observed with 5% total body water loss

Why isn't a patient considered dehydrated if they've lost 5% or less of their body weight?

because the body is still able to adjust by pulling water from the ICF

What is the powerful homeostatic response to dehydration?

THIRST

What is the equation for water deficit in a dehydrated patient?

Deficit(L) = % dehydration X BW(kg)

What steps should be taken to rehydrate a dehydrated patient?

1) calculate the deficit based on % dehydration, 2) give 1/2 of deficit in an initial bolus (patient dependent), and 3) replace the remaining half over the next 12 hours

What is the maintenance fluid requirements for adult dogs?

60ml/kg/day

What is the maintenance fluid requirements for adult horses?

50ml/kg/day

What is the maintenance fluid requirements for adult cats?

45ml/kg/day

When would you typically provide maintenance fluid therapy?

When a patient is unable to intake the appropriate amount of daily water, either due to sickness, a physical inability, or for horses - a reduced dietary/forage intake

Which phase of fluid therapy overlaps with the others?

Phase 3 - maintenance

What are two components of maintenance fluid therapy?

1) daily waiter requirements and 2) electrolyte supplementation when necessary

Calculate the maintenance fluid for an 18lb miniature schnauzer for the next 24 hours - ml/kg/hr

18lb/2.2 = 8.18kg

8.18kg x (60ml/kg/day) = 490.91 ml/kg/day

(490ml/kg/day) x (1day/24hrs) = 20.5 ml/kg/hr

What is an ongoing loss?

any losses of fluid/electrolytes that a patient may continue to lose due to their condition throughout the course of fluid therapy. Examples include vomiting, diarrhea, polyuria, etc.

For enteral fluid therapy, ____________ intubation is used in equine patients.

nasogastric

Which route(s) of fluid delivery absolutely requires a veterinarian?

Enteric fluid therapy in horses - placing an NG tube

How and how fast will fluid reach the vascular space via an enteral route?

takes a bit of time, absorbed through the large intestine

Why can't you use a subcutaneous route for fluid therapy in horses?

their subQ space is vanishingly small - ain't no room for fluids in there

What is the general rule for the limit of volume per injection site for subQ fluid delivery?

10ml/kg/site

How and how fast will fluid reach the vascular space via a subQ route?

relatively quick, will reach the vascular space via the interstitium

Of all the routes of delivery for fluid therapy - which would be the easiest to teach and allow an owner to administer?

subQ!

How and how fast will fluid reach the vascular space via an IV route?

It is directly administered the the ECF/vascular space via venipuncture. very fast!

What are common placement sites for IV catheter in dogs/cats? What size catheter should be used?

cephalic vein:18-22gauge

jugular vein: 18-16gauge

less commonly used is the saphenous vein.

What are common placement sites for IV catheter in horses? What size catheter should be used?

jugular vein: 10-14gauge

cephalic vein for horses with JV thrombus: 14-16gauge

in order of fastest to slowest of getting fluid to the vascular space, rank the different routes of fluid administration.

fastest: IV > subQ/enteral > oral slowest

An ideal catheter for IV fluid therapy is the __________ diameter possible to get the job done and is kept in place for the __________ amount of time necessary.

smallest (or large in number gauge), shortest

In what instance would a larger bore catheter be used for IV fluid administration?

in cases of emergency resuscitation

____________ fluid solution allows for brief volume expansion without causing electrolyte imbalances or fluid shifts from the ICF

isotonic

A hypotonic solution would ___________ volume of fluid in the ICF

increase

A hypertonic solution would ____________ volume of fluid in the ECF

increase

What is a crystalloid?

substance in a solution that is diffusible across a semi-permeable membrane

What are some situations where you might use a crystalloid solution?

resuscitation for volume depletion, maintenance fluid therapy, treatment of disease, irrigation of wounds, and peritoneal/pleural lavage

In what instance would you use caution when administering a crystalloid solution for fluid therapy?

decreased colloid osmotic pressure, head trauma, heart failure, etc

Crystalloid fluids have variable ___________.

tonicity

How does colloid fluid therapy work?

large molecules in the colloid solution remains in the vascular space and as a result, fluid is drawn from the interstitium into the vessel

____________ ________ solution provides immediate expansion of vascular volume.

hypertonic saline

When should hypertonic saline solution be used for fluid therapy?

small volume resuscitation

In what three instances should hypertonic saline fluid therapy be avoided or used with caution?

should NOT be used as a maintenance fluid therapy

caution in patients with chronic hyponatremia

caution in patients with poor ICF volume

Why would it be unwise to give hypertonic saline solution to a patient with low ICF volume?

this will only exacerbate their low ICF volume because hypertonic saline pulls water from ICF into the vascular space.

What are the three goals of fluid therapy for a patient that is hypovolumic/volume depleted?

1) improve circulating volume & blood pressure 2) prevent circulatory collapse, and 3) improve O2 delivery to tissues

skin tenting - ask what difference between present and normal is

What direction should catheter be fed?

What instances would prompt the use of colloid solutions for fluid therapy?

small volume resuscitation

Calculate fluid rates for individual patients in each of the following situations: Resuscitation, Rehydration, Maintenance, and Ongoing losses.

Assign appropriate route and solution for administration of fluid therapy - PRACTICE CASES FROM LAB

Compare and contrast clinical signs necessitating fluid therapy. Based on presented case information, determine if a patient is dehydrated or hypovolemic (volume depletion, reduced effective circulating volume).

Add anything from Clinical skills lab

Calculate 2 times the maintenance daily fluid requirement in drops per second for a 15lb DSH, if using a 60 drops/mL drip set.

1) 15lb/2.2 = 6.82kg

2) 6.82kg x (45ml/kg/day) x 2 = 613.64 ml/day

3) (613.64ml/day) x (1day/24hrs) x (1hr/60min) x(1min/60sec) = 0.0071 ml/sec

4) 0.0071ml/sec x (60drops/ml) = 0.43 drops/sec

If using a 60 drops/ml drip set and you've calculated your drops per second for a patient to be 0.43 drops/sec, what drip rate would you set?

(0.43drops/second) x 5seconds = 2.13 drops

2 drops in 5 seconds (rounding down)

What fluid solutions would you use for small volume resuscitation and why?

hypertonic saline & colloid fluids

hypertonic saline will provide immediate expansion of vascular volume

colloid fluid will draw fluid from interstitium into vessels