1. Fluid Therapy in the Surgical Patient
CTVT pgs
A&A pgs
(Anesthetist)

2. Objectives Understand the indications for fluid administration
Describe the different types of fluid available
List the reasons why an IV catheter is advised in surgical patients
Understand how to properly set up fluid administration sets and fluid associated equipment
Calculate fluid protocols for surgical maintenance and shock
Understand the risks & complications of IV catheter placement and fluid administration

3. General Fluid Treatment Questions
Daily maintenance fluids needed?
Dehydrated? Ongoing losses?
Surgical/Anesthetic rate only?

4. Daily Maintenance Requirements
Account for:
Sensible losses (measurable losses)
Insensible losses

5. Maintenance Rate _______ ml/kg/24hr Usually isotonic crystalloids
Canine: use the high side of the formula
Feline: use the low side
Isotonic fluids are most common

6. Maintenance Review Problem
A 24 lb dog is admitted to the clinic to be maintained on IV LRS:
Calculate this animal’s daily fluid requirement.
Calculate the rate that you would enter into your fluid pump.
Your clinic’s only pump is being used to correct hypotension in Dr. Dev’s dexmedetomidine dog. How many gt/sec will you set your fluid administration set to?
After 4 hours, the fluids are discontinued. How many milliliters did the animal receive in total?

7. Dehydration Requirements

8. Ongoing Losses
Every 1 ml lost = ___ mls of replacement fluid needed

9. Rehydration Formula Ex: 20 ml excessive urine = 40 extra ml of fluid
% dehydrated x body weight (kg) x 1000 ml/kg
= ml of fluid needed for replacement
To be given over a specified period of time
Isotonic crystalloids
We also have to account for ongoing losses!
Add to protocol: double the amount lost
Ex: 20 ml excessive urine = 40 extra ml of fluid

10. Rehydration Practice Problem
A 5 yr old, 11 lb Pomeranian is 6% dehydrated and has vomited about 25 mls since he was admitted to your clinic for surgery today. Your vet asks to correct his fluid status over the next 3 hours with IV LRS.
1. What vein would you most likely place an IV catheter in?
2. What gauge would you choose?
3. How many mls/hr will you set your fluid pump to?
4. gtt/sec?

11. Indications for Fluid Administration
Dehydration
Disease/illness/toxicity
Hypovolemia
Hypotension

12. Surgery is an indication for fluid therapy due to potential for hypotension and hypovolemia!
*Hopefully dehydration and diseases processes are corrected before surgery

13. Hypovolemia

14. Hypotension
Some anesthetic agents cause decreased ___________ ___________ and ________________ = HYPOTENSION

15. We know we need fluids…
Which route would we use to administer them?

16. Primary IV set for intravenous fluid therapy.

17. You can see the drops while manually calculating fluid drip rates here
Fluid bag
IV line attachment
Injection port
You can see the drops while manually calculating fluid drip rates here
Drip chamber
*Date bag when opened!

18. Patient= >10 kg
Patient= <10 kg

19. IV pumps come in many brands and sizes.
Fluid Stand
BAXTER 6300 DOUBLE PUMP

20. Fluid Pump Information
Rate: ____________
VTBI: ________________________
VI: __________________________
*Clear before connecting to a new patient

21. Syringe Pump

22. What type of fluids are needed in surgery?
The body maintains fluid balance (homeostasis) on a constant basis
Works via osmotic pressure
Normal osmolality of blood =
The fluids we choose are based on
this principle!

23. Crystalloids –vs- Colloids
Crystalloids are solutions of salts and water with variable electrolyte composition and contain no protein or colloids
How are these classified?
Colloids contain larger insoluble molecules, which act to retain existing fluid and promote increases in blood volume
How long would these fluids stay in the vasculature?

24. Isotonic Crystalloids
Most common type of fluids used to replace bodily fluids
Osmolality is __________ to blood osmolality
Classified as either saline OR balanced _______________ solutions
What are some other names for saline?
When do we use saline?
For each 1 ml increase in vasculature fluid you
want, must give 3-4 mls of isotonic fluid
Osmolality= to blood
Saline= irrigation, lavage, flush; hyponatremic
K, Mg, Ca and BUFFERED

25. Isotonic Crystalloids- BES
Solutions that have more electrolytes than just Na+ and Cl-
Most similar to normal bodily fluid composition

26. Anesthetic Protocol CATS: 3 ml/kg/hr DOGS: 5 ml/kg/hr
Isotonic crystalloids
Hypotension?
*Can increase to 20 ml/kg/hr (cats) and 40 ml/kg/hr (dogs)
What if that does not correct the problem?

27. Risks of Fluid Therapy Administering through a non-patent catheter:
Not priming the line:
Moving/transferring
the patient; setting up
equipment:
Fluid overload

28. Hypertonic Crystalloids
Saline greater than 0.9%
Administered for _______________ or ___________________
Greater osmotic pressure than blood
It has ___________ electrolytes than blood
Encourages movement of fluid into ___________________ (from the interstitial space)
Contraindicated in dehydrated or ______________ patients

29. *Provides more electrolytes than it provides water*
Hypertonic Saline
Quickly increases blood volume and pressure
For each 1 ml given, increases vasculature volume by 5-10 mls
Comparatively, dose is very __________
A little bit of fluid does a lot!
Why is this a quick fix (when compared to colloids)?
*Provides more electrolytes than it provides water*

30. Hypotonic Crystalloids
Examples:
0.45% Saline (NaCl)
BES: Normasol-M & Plasmalyte 56
Sometimes combined with dextrose
*Provide more water than electrolytes*

31. Crystalloid Effect on Body’s Cells
Normal plasma osmolarity = mOsm/L

32. Colloids Used for severe hypotension or hypovolemic shock
Natural: hypoproteinemia, acute blood loss, clotting disorders…
Synthetic: severe hypotension

33. Crystalloids – vs. - Colloids
LRS
Normosol-R/M
Plasma-Lyte 56/148
Sodium Chloride 0.9% (Normal saline)
3% Hypertonic saline
0.45% saline
Colloids
Natural:
Whole blood
FFP
Packed RBCs
Synthetic:
Hetastarch
Vetstarch

34. Resuscitation/Shock Protocol
Patient:
Is experiencing severe hypotension OR
Has lost significant amount of total blood volume
Dogs Cats
Isotonic fluids: ml/kg ml/kg
Hypertonic crystalloids: 3-4 ml/kg ml/kg
Colloids: ml/kg ml/kg

35. Hypovolemic/Hypotensive Shock
Give ¼ of total dose as a bolus
How do we bolus fluids?
Check parameters and reassess

36. Resuscitation Practice Problem
A 3 year old 50 lb Labrador retriever is in hypovolemic shock and needs IV Hetastach per Dr. Dev.
What is the total dose of Hetastarch in milliliters?
2. How much Hetastarch will you bolus initially?

37. General Rules of Thumb Warm those fluids! Monitor for hypervolemia
Where should warmer be placed?
Monitor for hypervolemia

38. Hypervolemia: Causes Human error: Fluid Intolerance:
Excessive total volume given
Excessive rate of fluid administration
Fluid Intolerance:
Decreased cardiac or kidney function

39. Hypervolemia: Clinical Signs
Tachypnea- due to pulmonary edema (1st sign!)
Serous nasal discharge
Chemosis- edema of the ___________ conjunctiva
Pitting edema –skin remaining indented for a prolonged amount of time after removal of firm finger pressure
(Over saturation of the cells)
Restlessness and coughing-
during recovery

40. Anesthetic Protocol Calculation
Your next surgical patient is a 28 lb spaniel mix OHE. Her blood work was WNL and she has no known disease.
1. What fluid type will your vet most likely choose?
2. What will the rate of fluid administration be per hour?
How many gtt/sec will you set your line to?
Quick formula:

41. Supplemental Reading AAHA Fluid Therapy Guidelines
More calculation examples on page 38 of A&A