Lecture VI: Fluid Therapy

126 | C r i t i c a l C a r e

Lecture VI: Fluid Therapy Andrew J Rosenfeld, DVM ABVP Elizabeth Dunphy, DVM AVECC

The goal of this chapter is for the team member to get a basic understanding of the goals of intravenous therapy, how to calculate a fluid rate for the pet, how to monitor intravenous fluids, and how to discuss treatment concerns with the client. Administration or changes to fluid therapy should never be done without proper instruction and consent from the veterinarian. It is essential to have a well educated hospital team that can monitor a patient on intravenous fluids for dehydration, fluid overload, and fluid INS /OUTS. In specific cases where there are increased toxins in the blood stream secondary to renal disease, liver disease, certain forms of diabetes, or other toxic or systemic diseases; increased amounts of fluids (1 ½ ‐ 2 x maintenance) can aid in removing toxins from the body (Diuresis). The goal of fluid maintenance is to provide support to aid in rehydration, maintenance and possibly diuresis for the pet. Fluid support is the key hallmark for stabilization in a majority of emergency care. Necessary supplements and drugs can be added to the fluid regime to aid in the pet’s recovery. Nutrients like Dextrose and Potassium, and medications like Metoclopramide, Lidocaine, and Dopamine, can be added to intravenous fluids to provide a continuous rate of infusion (CRI) of the needed drug. Types of fluid support: Fluid support can be given in two forms, subcutaneous fluids and intravenous fluids. Each type of administration has its own strengths and weakness to help the ill patient. • Subcutaneous Fluids:

o General: Subcutaneous fluids are a moderate to large bolus of fluids given under the skin to create a fluid repository that can be slowly absorbed by the pet over a 3‐6 hour period of time.

o Indications: Subcutaneous fluids are meant for slow replenishment of the mild

to moderately dehydrated patient. Indications for utilization can be:

o Acute disease producing mild dehydration – for example:

Mild Gastrointestinal Disease Mild Upper Respiratory Infections


o Chronic Disease: Subcutaneous fluids are used with pets with chronic disease at regular intervals to help maintain their hydration. These patient’s diseases are usually under control and the pet’s are eating, drinking and feeling well. Examples of chronic disease where subcutaneous fluids can be given are:

Chronic renal disease Chronic liver disease

These fluids can be done in the hospital setting, or the owner can be taught to administer subcutaneous fluids at home.

• Emergency Conditions: Although not as valuable as intravenous fluids in

emergency situations, subcutaneous fluids can help to mildly rehydrate a patient that has severe perfusion problems. Once subcutaneous fluids are administered and absorbed, a vein may be more easily catheterized.

• Contraindications: With proper administration of subcutaneous fluids, there are

few contraindications. However some concerns are: • Intravenous Fluid Additives: Some caution must be exercised that certain fluid

additives (i.e. dextrose), which are normally given intravenously, are not given subcutaneously. These types of fluid additives can cause irritation and damage to the overlying skin.

• Underlying disease conditions: Caution should be exercised with patients that

have underlying disease conditions that have the propensity for pulmonary edema. Although of much less concern then when using intravenous fluids, repeated subcutaneous fluids may increase the likelihood of buildup of fluid within the lung fields. Some of these conditions are:

• Congestive Heart Failure • Severe Renal Disease (End Stage) • Drowning • Electric Cord Injury

• Calculation of Fluid Need: The veterinarian will make recommendations for

subcutaneous fluid boluses for the pet. However, the veterinary team should have an understanding of approximate fluid parameters to prevent miscommunication or over administration of fluids (See Table 6.1).


Table 6.1: Guidelines for Subcutaneous Fluid Therapy • Intravenous Fluids

• General: Intravenous fluids are one of the hallmark treatments for the

hospitalized and emergency care patients in practice. Team members must be able to:

Master evaluating dehydration Understand the benefits and concerns with different fluid types (i.e.

crystalloids vs. colloids) Understanding how to calculate fluid need Monitoring a patient on intravenous fluids Properly documenting the fluid administration

There are two larger groups of intravenous fluid choices, they are:

• Crystalloids: This category is made up of types of fluid that have a similar concentration (isotonic) density as blood. The goal of these fluids is for long term intravenous administration for patients needing rehydration, dieresis, and emergency care. Examples of commonly used crystalloids are 0.9 % NaCl, Lactated Ringers Solution (LRS), and Normosol

• Colloids: This category is made up of fluid types that have an increased

density (hypertonic) as compared to blood. These fluids are separated into two further categories, which are:

5 These fluids are suggestion of fluid ranges based on pet’s weights. These ranges are meant for animals without primary disease that could produce pulmonary edema and congestion (i.e. Congestive Heart Failure, Electric Cord Injury…).

Animals Weight Approx Subcutaneous Fluid Amount 5

< 10 pounds 50‐200 ml

11‐40 pounds 200‐500 ml

41‐70 pounds 500‐700 ml

70 pounds + 700‐ 1000 ml +


o Natural Colloids: refer to blood, packed red blood cells and

plasma that are meant for blood replacement products in anemic or bleeding animals.

o Synthetic Colloids: refer to hypertonic solutions that are used for

shock and emergency patients to help increase systemic blood pressure or serve as a blood replacement product. (See below).

• Applications and administration of Intravenous Fluids – Crystalloids:

• General: Crystalloids are fluids containing electrolyte and non‐

electrolyte solutes capable of entering all body fluid compartments. They are the most common form of parenteral (non‐oral) fluid therapy and are classified as replacement solutions (composition resembling extracellular fluid) or maintenance solutions (See Figure 28.2). The choice of fluid depends upon the disease process. The most useful crystalloid solutions for routine use are balanced replacement solutions such as Ringer’s or Lactated Ringer’s Solution, Normosol R, 0.9% Saline and 5% dextrose in water.

• Indications: Crystalloid fluids are indicated for the treatment of ill

patients that need rehydration, dieresis, or emergency care. Intravenous support can be given over hours to days safely. Nutrients such as dextrose and potassium chloride can be added to fluids to help provide minimal nutritional support as well as balance electrolytes. Further, drugs (such as Metoclopramide and Lidocaine) can be given for continuous administration (CRI – continuous rate infusion) of the sick patient.

• Contraindications: Since intravenous fluids provide a constant flow

of liquid directly into the vein, caution must be exercised with patients with specific diseases. Careful monitoring is necessary for patients with underlying disease conditions that have the propensity to produce pulmonary edema. Since these pets cannot control the rate at which fluids enter their body, the patients can become over hydrated and begin building up fluid within the lung tissue (pulmonary congestion). Some diseases that require caution are:

Congestive Heart Failure Severe Renal Disease (End Stage) Drowning Electric Cord Injury


Further, animals that have diseases producing profound anemia or blood loss can be made worse with high volumes of intravenous fluids. These patients do not have enough red blood cells to carry oxygen to the body. If too much intravenous fluids are administered, the blood can become more dilute decreasing its oxygen carrying capacity. Some potential disease producing a serious acute or chronic anemia:

• Chronic Renal Disease (See Chapter XIII) • Chronic Liver Disease (See Chapter XIV) • Blood Loss / Trauma (See Chapter XXX) • Autoimmune Hemolytic Anemia

• Calculation of Fluid Need:

• General: Calculation of fluid need is dependent on:

• The pet • The disease • Fluid losses (i.e. diarrhea and vomiting) • The pet’s level of dehydration • If the pet is in shock

The treatment amounts are up to the veterinarian’s recommendations. However, the team member must have a concept of the type, the daily fluid needs and rates of fluids given in order to make sure the pet is getting an adequate amount of fluids to rehydrate while not overloading. The categories for rehydration are as follows:

• Maintenance: Maintenance fluids are the minimum amount of fluids needed given to a pet that is not having significant fluid losses (i.e. vomiting or diarrhea) to maintain normal hydration. All animals require 66 ml / kg / day fluids for the body to function normally.

Maintenance = BW (kg) x 66 ml/ kg/ day

• Dehydration: Dehydration is a qualitative measurement of dehydration level of the patient based on skin turgor, gums, eye appearance, and / or packed cell volume. As discussed in Chapter VI, dehydration is based on the following scale:


• 0‐3%: Undetectable dehydration secondary to an animal that has been

vomiting or having mild diarrhea.

• 5‐7%: Beginning of detectable dehydration with slight decrease in skin turgor and beginning of dry gums.

• 7‐9%: is more perceivable dehydration with much more decreased elasticity

of skin, dry gums and sunken eyes.

• 9‐12%: Life threatening dehydration with no elasticity of skin, sunken eyes, dry gums, depression and weakness.

Calculating for dehydration uses the following formula:

Dehydration= % Dehydrated in decimal form x wt (kg)*1000 ml/l

Hourly fluid rate: Hourly fluid rate is calculated by taking total fluid need and dividing by 24 hrs / day. Formula:

Hourly Fluid Rate = (Total Fluid Need / day) / (24 hours / day)

Bolusing Fluids: In times of severe dehydration, prior to a surgery or treatment, the doctor may want to give an intravenous bolus to help recap the fluid loss more quickly. There is no specific amount of fluids administered; however, a general guide for bolusing patients can be 10 ‐ 20 % of total fluid for that day. The overall bolus is subtracted from total fluid need and then hourly fluid rate is calculated. When bolusing fluids, the patient must be monitored for fluid overload (see below).

To calculate drops per second:

Drops / Second = mls / second x drops / mls (drip system)

Chronicity Strip: Once drops / second is calculated, a chronicity strip can be used to make sure the animals hourly needs are being calculated (See Figure 28. 3). This type of strip, usually made of 1‐inch white tape, is placed on a bag of fluids and the times are correlated with what the estimated fluid levels should be at that given time. This allows the technician the ability to adjust the fluid rate as it is checked every 1‐2 hours.


Selecting IV Fluid Care:

Fluid Type Indications for use Contraindications

0.9 % NaCl Rehydration, Diuresis, and Maintenance

Acidotic Patients (Addisonians, Metabolic

Acidosis Patients

LRS (Lactated Ringer Solution)

Rehydration, Diuresis, and Maintenance,

Hypocalcemia Patient Liver Patient

Normosol / Plasmalyte

Rehydration, Diuresis, and Maintenance

0.45 NaCl & 5% Dextrose

Fluid support of the cardiac patient HYPOTENSION


IV Fluid Administration Algorithm

Step I: Maintenance Fluids:

______Wt (kg) * 66 ml/kg/day = ________ ml/ day

Step II: Dehydration:

______Wt (kg) * ____% Deny * 1000 ml/l = ______ ml/ day

Step III: Total Fluid Need (TFN)

TFN = Maintenance = Dehydration

Step III a: Bolus:

Bolus = TFN * 0.2

Step III b: recalculate TFN

NEW TFN = TFN - Bolus

With Fluid Bolus

Step IV: Hourly Rate (HR)

Hourly Rate = TFN / 24 hrs

Without Fluid Bolus

Step V: Drops / Second

mls / Sec = HR / 3600 sec

Sec = ______ / 3600 = _____

Drops / Sec

Identify IV Set drops / ml


Fluid Therapy for Shock: There are times when an animal is in a life threatening condition, shock, or cardiovascular shut down when Emergency Fluid Dose may need to be given. At this time, this patient needs high fluid volumes to maintain their blood pressure and cardiac output. Emergency dose of fluids are not associated or subtracted from daily need, they are given until normal perfusion and cardiac output are returned and the patient is no longer in shock. General guidelines for emergency boluses are:

Dogs: 90 ml/ kg / hr * wt (kg) Cats: 45 ml/ kg / hr * wt (kg)

Due to the life threatening emergency, these fluids are given as quickly as possible, often with a high‐pressure bag to maximize fluid administration (See Figure 28.4). It important to understand that these shock doses represent the maximum amount of fluids a “healthy” pet can receive in 1 hour before fluid begins to build up within the tissue. There are many patients that cannot tolerate these large doses, and the animal must be closely monitored for fluid overload while shock doses are being administered. Once the pet is stabilized, it is re‐evaluated by the veterinarian and hourly fluid rate is reassigned dependent on dehydration, medical disease, and current physical condition. Please refer to table 28.2 for a rough overview of fluid need based on the patient’s physical condition.


Estimation of fluid administration need dependent on hydration and fluid loss status 6

Species

Condition

Significant

V / D

Suggested Fluid Administration Level

Feline & Canine

0‐5 % Dehydrated / Stable

N Maintenance –‐> 1 ½ x Maintenance

Feline & Canine


Y Bolus + 1 ½ ‐2 x/ Maintenance

Feline & Canine

7‐ 9 % Dehydrated / Stable

N Bolus + Maintenance –‐> 1 ½ x Maintenance

Feline & Canine

7‐ 9 % Dehydrated / Stable

Y Bolus + 2x Maintenance

Feline & Canine


N Bolus + 2 x Maintenance

Feline & Canine

9‐12% Dehydrated / Stable

Y Bolus + 2 x/ Maintenance

Feline Unstable Y or N Shock Fluid Doses (45 ml/ kg/hr)

Canine Unstable Y or N Shock Fluid Doses (90 ml/ kg/hr)

6 This table is a rough estimate of fluid need and should be only used as a reference source for the medical team member to ascertain the relative fluid level needed for a sick patient. All fluid administration rates are based solely on the veterinarian recommendations.


Complications‐ Fluid Overload refers to the situation when an animal is receiving too many intravenous fluids or receiving fluids too quickly. If too much fluid is given, the excess fluid can begin to pool outside of the vessels and produce fluid buildup in the tissue. If enough fluid accumulates in the lungs, the pet can drown. Signs of fluid overload:

• Clear nasal discharge as fluids are being given. • Licking lips • Acting nauseous • Fluid buildup in feet under neck – edema. • Increased respiratory effort and respiratory crackles are evident.

Applications and administration of Intravenous Fluids – Colloids:

• General:

• Colloids are large macromolecular synthetic solutions (i.e. Hetastarch, Pentastarch) or natural solutions (i.e. Blood, Plasma, Packed Red Blood Cells) are used in the treatment of shock and the maintenance of intravascular fluid balance.

• These large dense molecules enter the blood vessels and increase the amount of fluid drawn into the vessels and result in an increased blood pressure. .

• Reduce the total fluid need of the patient by 40‐60%.

• There are two categories of colloids: Natural and Synthetic

Natural colloids include whole blood, plasma products and albumin.

Synthetic colloids are formulated from various sources, such as gelatins,

polysaccharides (dextrans) or amylopectins (Hetastarch).

• Pharmacologic classification is based upon molecular weight, plasma half‐life and colloid oncotic pressure. Each colloid solution within these groups has specific characteristics, qualities and side effects, which must be considered in the selection of the appropriate therapy for each patient.

• Indications: Colloids can serve two overall functions:


• To increase fluid uptake into the vessels from the tissue increasing blood pressure. The colloids generally used for this function are:

Hetastarch Pentastarch

• To replace necessary blood factors needed for oxygenation of tissue, clotting of

blood and wound healing. The colloids used for this function are:

• Packed Red Blood Cells: Serves as a source of red blood cells to help the patient increase their packed cell volume and increase the oxygen carrying capacity of their blood.

• Plasma: is the fluid portion of blood which carries the proteins necessary for

clotting blood. Further, plasma is rich in a protein called albumin, which maintains blood pressure by drawing water into the blood vessels as well. Without proper levels of albumen in the blood, fluid can pool into tissue causing edema and decreasing blood pressure. Further, albumin is a key protein in tissue healing.

• Contraindications: Each of these colloids has their own limitations dependent on

the patient’s condition. The main contraindications are:

• Allergic Reaction: These chemicals can produce moderate to severe allergic reaction in the pet, and should always be administered slowly in a hospitalized situation.

• Dehydration: Further, since these drugs function also to pull fluid into the vascular supply, the pet must be reasonably hydrated before administration. Giving colloids to a dehydrated animal can lead to further dehydration and poor circulation as the body is unable to move these larger molecules to the blood stream.

• Calculation of Fluid Need: The only colloid that will be discussed for calculation

information is Hetastarch. Hetastarch is given in emergency cases when normal intravenous fluids are not returning normal perfusion and strong pulses to the shocky patient. As with all other fluid calculations, recommendations for fluid administration are made by the veterinarian. However, in an emergency situation, the medical staff should have an understanding of the needs patient and anticipated the veterinarian to be ready to begin treatment of a life‐threatened pet.


Colloid Type Reason Dose Concerns

Hetastarch Hypotension Feline: 11‐ 15 ml / kg /day

Canine: 11‐22 ml / kg /day

Allergic Reaction

Core Dehydration

Tissue 3rd Spacing

Plasma Clotting Factors 1 unit / 20 pounds Allergic Reaction

Plasma Hypoalbunemia 45 ml/kg to raise Albumin 1.0 gm/dl Allergic Reaction

Whole Blood Active Bleeding 1 cc/lb to raise PCV 1 % Allergic Reaction

Hemolysis

Packed Red Blood Cells Anemia / Bleeding 1 cc / pound to raise PCV 1.5 %

Allergic Reaction

Hemolysis

• Complications: Colloids can produce mild to severe allergic / anaphylactic

reactions to administration. Patients should be always maintained in a hospital setting under direct supervision. Fluids should be given slowly initially to make sure the pet is not having any severe reaction, especially in felines. Although, this is an uncommon complication, the pet must be closely monitored for:

• Increasing dehydration • Increased Respiratory Effort • Increasing Heart / Pulse Rate • Paling of the mucus membranes


• Respiratory Wheezing • Decreased Mentation / Responsivity • Lateral or Sternal Recumbence • Collapse • Cardiopulmonary Arrest (Severe Cases)

• Administration:

• Hetastarch can be administrated by a number of procedures. Two possible

procedures can be:

• Small patient (<10 pounds) (Requirements of < 75 ml): The hetastarch can be mixed with an even volume of intravenous fluids in an IV burette system and given over 30‐120 minutes.

• Larger Patient (>15 pounds) (100‐500 ml): The medication can be given

directly into a catheter over 30‐90 minutes. Further the drug could be drawn up into a number of syringes and injected into the IV line over the same period of time.

• Whole blood: Whole blood is indicated for excessive blood loss when both cells and volume are needed or in patients with both anemia and coagulation factor deficiencies>

• Dosages (One of the following):

1) Volume to be transfused=

90ml (dog) or 60 ml (cat) X Recipient. BW (kg) X (Desired PCV‐Actual PCV)

Donor's PCV

2) 12‐25 ml/kg

3) 2 ml/kg whole blood with PCV 40% will raise recipient hematocrit 1 %


4) 1.0 ml blood per 1 lb recipient weight will raise PCV by 1 %

• Rate of administration: Start all transfusions at 0.25 ml/kg for first 15 minutes to monitor for any transfusion reactions. Thereafter the rate can be increased to 5‐10 ml/kg/hr, Blood products should not be given over more than 4 hours though∙ and most people simply calculate the rate of administration by dividing the total volume needed by 3 or 4 hours. Care must be taken with those patients that are at risk for fluid overload. The maximum rate for such patients is 4/mlIkglhr.

• Storage: Canine and feline RBCs are viable for 3‐4 weeks depending on the anticoagulant used. Whole blood must be refrigerated.

• Packed red blood cells (PRBC) Packed red blood cells are indicated for anemia due to blood loss, hemolysis, and bone marrow dysfunction.

o Dosage: 6‐10 ml/kg.

o Rate of administration: Same as for all blood products. Start slowly at 0.25 ml/kg/hr for the first hour and then increase to 5‐10 ml/kg/hr.

o Storage: The storage of PRBC is the same as that for whole blood. PRBC must be refrigerated and are viable for approximately 3 to 4 weeks.

• Plasma Fresh Frozen Plasma: Plasma transfusions are used to replace hemostatic proteins, namely the clotting factors, von Willebrand’s factor and fibrogen and fibronectin. The products used to replace hemostatic proteins are:

o Fresh Frozen Plasma is typically used as a source of clotting factors. Indications include hepatic dysfunction, anticoagulant rodenticide toxicity, hemophilia B, von Willebrand's deficiency and hemophilia A (cryoprecipitate is a better choice though), and DIC.


FFP is not a reasonable choice to replace albumin though as the volume of plasma required to cause a significant affect on protein counts is not practical. It takes 45ml/kg to raise albumin 11 g/dl.

Dosage: 6–10 ml/kg

Rate of administration: Similar to all blood products, start at 0.25 ml/kg/hr to monitor for transfusion reactions and then increase to 5‐10 ml/kg/hr. As with PRBC, plasma should not be delivered over greater than 4 hours.

Storage: FFP can be stored at ‐20 Degree Celsius for 1 year.

• Cryoprecipitate: Indicated in Hemophilia A, von Willebrand's Disease, generalized sepsis, DIC and fibrinogen deficiency. The advantage of cryoprecipitate over FFP is that its use requires a much lower volume, which minimizes the risk of volume overload.

• Dosage: 1 unit/10 kg every 12 hours as needed

• Storage: Can be stored at ‐20 degrees Celsius for up to 1 year.

• Cryosupernatant: Indications for use the same as FFP with the exception of von Willebrand's disease, hemophilia and fibrinogen deficiency, as these factors are removed with the cryoprecipitate.

o Dosage: 6‐10 ml/kg

o Rate of administration: Similar to all blood products, start at 0.25 ml/kg/hr to monitor for transfusion reactions and then increase to 5‐10 m1/kg/hr. As with PRBC, plasma should not be delivered over greater than 4 hours.

o Storage: Cryosupernatant can be stored at ‐20 Degree Celsius for 1 year;


• Replacement of Platelets: The replacement of platelets is very difficult to say the least. It is not done very frequently since the major cause of thrombocytopenia in veterinary patients is Immune Mediated Thrombocytopenia and the transfused platelets are quickly destroyed. In addition, the clinical signs of bleeding do not usually occur unless platelet count is below 50,000. If the hematocrit is stable and any bleeding considered minimal than the transfusion of platelets is rarely indicated. Transfusing platelets may be indicated prior to a surgical procedure, if an intracranial bleed is suspected, or with platelet function defects such as NSAID overdose. If transfusing platelets is desired, than there are two available blood products.

o Platelet Rich Plasma / Platelet Concentrate Dosage:

PRP 6 – 10 ml/kg

PC 1 unit/10 kg

• Platelet Phoresis is now a source of platelets. This process is able to greatly concentrate platelets so that > 1 million platelets are transfused. The product is very expensive and currently needs to be shipped in from Midwest Animal Blood Services.

Crossmatching and Transfusion Reactions

• Blood types: Blood types are genetic markers on the erythrocyte surface that are antigenic and species specific.

• Dogs:

• Dogs do not have true “blood types” as the term is used for humans and cats. The dog instead has Dog Erythrocyte Antigens (DEA), which are numbered 1.1, 1.2, 3, 4, 5, 6, 7, 8.Clinically the most important are 1.1, 1.2 and possibly 7. Dogs can be 1.1 positive or negative.

• If DEA 1.1 negative, they can then be DEA 1.2 positive or negative. DEA 1.1 is strongly antigenic.A first time transfusion of DE A 1.1 positive blood to a DEA 1.1 negative dog will elicit a strong alloantibody response.


• These alloantibodies may not develop for up to 4 days and can cause a delayed transfusion reaction. A previously sensitized dog can have an acute hemolytic reaction.

• Cats:

• Like everything else in medicine, cats are different from dogs. Cats have only 3 blood types, A B and AB.

• These blood types have a unique inheritance pattern. The A allele is dominant to B allele. Type A cats are either A/A or A/B. Type B cats must be B/B, AB is very rare and involves the inheritance of a 3rd allele. In the United States Type A is the most common; the frequency of type A vs. B cats varies among breeds and geographical regions.

• In contrast to dogs cats have naturally occurring alloantibodies against the blood type antigen they lack, i.e. do not need to be sensitized. Type B cats have very strong anti~A antibodies.

• A transfusion of Type A blood to a Type B cat will result in a very serious, acute hemolytic reaction, usually fatal. Cats can also have neonatal isoerythrolysis. (AI AB kittens receiving anti‐A antibodies from a type B mom's colostrum.) .


• Blood typing techniques: In house cards are available that type dogs as DEA 1.1 positive or negative as well as cards that type cats as A, B, AB positive or negative. Blood can be sent out to specialized labs to type dogs DEA 1.1, 1.2,3,4,5, and 7

• Cross matching:

• Cross matching indicates the serologic compatibility or incompatibility between the donor and the recipient. Alloantibodies can be hemolyzing or hemoagglutinating.

• A major cross match measures alloantibodies in the recipient's plasma against the donor's cells. A minor cross match measures alloantibodies in the donor's plasma against the recipient's cells,

• A previously transfused dog must have a crossmatch prior to an additional transfusion. Antibodies can be induced as quickly as 4 days and can be present for years. A dog that has truly never been transfused potentially can skip a crossmatch but a blood type should be done.

• Cats must be typed or cross‐matched even on the first transfusion because of naturally occurring alloantibodies.

Administration Techniques: When administering any colloid, a hospital protocol should be set up for administration of the fluid. Although hospitals differ, one suggested protocol is

1. Maintain IV Fluids while a transfusion is being given: Maintaining IV fluids help to maintain hydration and decrease the likelihood of transfusion reaction. Further it allows a port for medication if needed.

2. Premedicate the patient: If the patient is set for receiving a natural colloid (blood, plasma, packed RBC) many teams will premedicate patient with diphenhydramine.

3. Set a secondary IV catheter and begin transfusion of colloid: Have a team member evaluate the animal every 5 minutes for the first 30‐60 minutes while a transfusion is being given. Each time the patient’s vitals are recorded and the patient is checked for:

a. Increasing Heart Rate

b. Decreasing Pulse Quality

c. Panting


d. Increase in Body Temperature

e. Increase in Respiratory rate

f. Change in Mentation

If noted, the transfusion is temporarily stopped and the veterinarian is contacted immediately. Many times fluid rates will often just be slowed.

4. If transfusing whole blood or packed RBC: Team members should recheck PCV / TP when the transfusion is 50% completed. In some cases the animal’s PCV will dramatically increase above expected goals and to prevent colloid overload, the transfusion may need to be slowed or stopped. Serum color should be evaluated for hemolysis as well.

5. Continue the transfusion over the next 3 hours: If no reaction is noted at this point, the transfusion rate should be continued over the next 3 hours. Team members should monitor this patient every 10‐15 minutes until the transfusion is completed.

6. If transfusing whole blood or packed RBC: Team members should recheck PCV / TP when the transfusion is completed to evaluate final effect of transfusion and to see if other transfusions may be required in the future. Serum color should be evaluated for hemolysis as well.

• Transfusion reactions:

• Hemolysis

• Urticaria/edema

• Hypotension

• Treatment consists of immediately stopping the transfusion and administering short‐ acting corticosteroids and/or diphenhydramine. Serious reactions may require treating with epinephrine.


• Non‐immune‐mediated reactions are usually caused by human error. These include:

• Circulatory overload

• Sepsis from contaminated product

• Hypocalcemia

• Hemolysis from contact with hypotonic solutions

• Agglutination from contact with calcium containing solutions

• Disease transmission (Heartworm, Babesia, Hemobart, Ehrlichia, FELV, FIV)

Blood Collection and Donor Selection

Anticoagulants Citrate acts as an anticoagulant by inhibiting calcium dependent steps of the clotting cascade, other additives include buffers and red blood cell energy sources. The 2 most common anticoagulants used are:

Citrate‐phosphate‐dextrose‐adenine (CPD A): Use a 1:9 dilution, meaning add 1 m1 of CPDA for every 9 m1 of blood. With CPDA canine RBCs are viable for up to 4 weeks

Acid‐citrate‐dextrose (ACD): Use a 1:6 dilution, meaning add 1 m1 of ACD for every 6 m1 of blood. With ACD canine RBCs are viable up to 3 weeks and feline RBCs are viable up to 30 days,

Canine Donors: Their weight should ideally be greater than 25kg and their age ideally 2‐8 years old. The hematocrit needs to be >40%. The dogs need to be healthy and free from blood borne diseases with a known blood type. Ideally 1.1, 1.2 and 7 should be determined. Finally the dogs should have a known von Willebrand’s factor status

Collection technique: The jugular vein is preferred for blood collection. Sterile techniques must be employed. The maximum donation for any one donor is


22ml/kg every 3‐4 weeks. Replacement fluids are necessary if more than 5% of a donor's blood volume is donated. The use of a commercial triple pack collection system is preferred. These bags contain the anticoagulant CPDA and a RBC nutrition source already added

Feline: Their weight should be greater than 5 kg and their age between 2 and 8 years old. The hematocrit needs to be greater than 30 %. The cats need to be healthy and free from blood borne disease with a known blood type.

Collection technique: Sedation is usually required when drawing blood from a donor cat. As in dogs, the be taker from anyone donor is 15m/kg every 4 weeks. NEVER take more than 60 ml at one time from a donor cat. Frequently the dose needed for the patient is greater than 60 ml, but unless it is a very large cat, 60 m1 is the maximum amount a cat can safely donate at one time. Replacement fluids are necessary if more than 5% of donor's body weight is donated.

Lecture VI: Fluid Therapy

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