Fluid Therapy in the Surgical Patient CTVT pgs

Fluid Therapy in the Surgical Patient CTVT pgs. 883 -894 A&A pgs. 27 -47 (Anesthetist)

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

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

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

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

Maintenance Review Problem A 24 lb dog is admitted to the clinic to be maintained on IV LRS: 1. Calculate this animal’s daily fluid requirement. 2. Calculate the rate that you would enter into your fluid pump. 3. 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? 4. After 4 hours, the fluids are discontinued. How many milliliters did the animal receive in total?

Dehydration Requirements

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

Rehydration Formula % 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

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?

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

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

Hypovolemia

Hypotension Some anesthetic agents cause decreased ___________ and ________ = HYPOTENSION

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

Primary IV set for intravenous fluid therapy.

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!

Patient= >10 kg Patient= <10 kg

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

Fluid Pump Information �Rate: ______ �VTBI: ____________ �VI: _____________ *Clear before connecting to a new patient

Syringe Pump

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!

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?

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

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

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?

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

Hypertonic Crystalloids Saline greater than 0. 9% �Administered for __________ �Greater osmotic pressure than blood �It has ______ electrolytes than blood �Encourages movement of fluid into __________ (from the interstitial space) �Contraindicated in dehydrated or _______ patients

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*

Hypotonic Crystalloids �Examples: � 0. 45% Saline (Na. Cl) �BES: Normasol-M & Plasmalyte 56 � Sometimes combined with dextrose *Provide more water than electrolytes*

Crystalloid Effect on Body’s Cells Normal plasma osmolarity = 290 -310 m. Osm/L

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

Crystalloids – vs. - Colloids �Crystalloids �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

Resuscitation/Shock Protocol �Patient: �Is experiencing severe hypotension OR �Has lost significant amount of total blood volume Dogs Isotonic fluids: 80 -90 ml/kg Hypertonic crystalloids: 3 -4 ml/kg Colloids: 10 -20 ml/kg Cats 55 ml/kg 2 -3 ml/kg 5 -10 ml/kg

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

Resuscitation Practice Problem �A 3 year old 50 lb Labrador retriever is in hypovolemic shock and needs IV Hetastach per Dr. Dev. 1. What is the total dose of Hetastarch in milliliters? 2. How much Hetastarch will you bolus initially?

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

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

Hypervolemia: Clinical Signs �Tachypnea- due to pulmonary edema (1 st 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 coughingduring recovery

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? 3. How many gtt/sec will you set your line to? Quick formula:

Supplemental Reading AAHA Fluid Therapy Guidelines https: //www. aaha. org/professional/resources/fluid_therap y_guidelines_abstract. aspx More calculation examples on page 38 of A&A