19. fluid therapy and emergency drugs

Chapter 19

Fluid Therapy and Emergency Drugs

Copyright © 2011 Delmar, Cengage Learning

Basics of Body Fluid

• Water is the primary body fluid• Body water is distributed among three types of

compartments: intracellular, intravascular, and interstitial– Intracellular fluid (ICF) = fluid within the cell

(two-thirds of body water)– Extracellular fluid (ECF) = fluid within the blood

vessels and in the tissue spaces between the blood vessels and cells (one-third of body fluid)



• Body water contains solutes (substances that dissolve in solvent; particles)– Electrolytes are substances that split into ions when

placed in water– Primary ions in the body are sodium, potassium,

chloride, phosphate, and bicarbonate• Cations are positively charged ions• Anions are negatively charged ions

• Body water is the solvent in biological systems• To establish equilibrium, body water moves along its

concentration gradient



• Extracellular fluid shifts between the intravascular space (blood vessels) and the interstitial space (tissues) to maintain a fluid balance with the ECF compartment

• Fluid exchange occurs only across the capillary walls

• Fluid therapy in animals may involve the use of crystalloids and/or colloids

• Crystalloids are diffusible substances that dissolve in solution

• Colloids are nondiffusible substances


Fluid Therapy

• The basis for fluid therapy depends on the animal’s hydration status (refer to Table 19-1 in your textbook)

• Fluid therapy can replace water, sodium, potassium, and chloride electrolytes, and restore hydrogen ion balance (pH balance)


Fluid Administration

• Intraperitoneal fluids– Given when IV access is not available– Injection site must be aseptic– Disadvantages include:

• The possibility of sepsis• Can’t use IP routes in animals awaiting abdominal

surgery• Inability to use hypertonic solutions


Routes of Fluid AdministrationRoute of administration

Advantages Disadvantages

Oral • Safest route• Easy

• Less rapid absorption• Possible aspiration• Cannot use for vomiting animals

Subcutaneous • Relatively easy to administer• Absorption distributed over time

• Possible infection• Must use isotonic fluids• Slower absorption


Routes of Fluid AdministrationRoute of administration Advantages Disadvantages

Intravenous • Precise amount given is available rapidly • Various tonicities of fluid can be used

• Possible fluid overload and vessel damage• Requires close monitoring• Must be sterile

Intraperitoneal • Relatively rapid absorption• Can be used when IV access is not available

• Possible infection• Cannot use hypertonic solutions• Abdominal surgery hindered after administration


Routes of Fluid Administration

Route of administration

Advantages Disadvantages

Intraosseous • Useful for small animals, birds, and pocket pets• Can be used when vein inaccessible• Rapid absorption

• Lack of confidence in administering fluid via this route• Possible infection

Rectally • Good absorption• Rapid absorption

• Not frequently used


Tonicity of Fluids

• Tonicity refers to the osmotic pressure of a solution based on the number of particles per kilogram of solution (osmolality)

• An isotonic solution has the same osmotic pressure as blood and extracellular water

• A hypotonic solution has osmolality lower than that of blood; RBCs can swell

• A hypertonic solution has osmolality higher than that of blood; RBCs can shrink


Types of Crystalloids

• Isotonic– 0.9% sodium chloride (normal saline)– Lactated Ringer’s solution– Normosol– Plasmalyte

• Hypotonic– 5% dextrose in water (D5W)– ¼ NS (0.25% normal saline)– ½ NS (0.45% normal saline)

• Hypertonic– 0.9% normal saline with 5% dextrose– 10% dextrose in water– 3% normal saline


Problems With Fluid Administration

• Fluid overload is a condition in which the administration of fluid occurs at a greater rate than the rate at which the body can use or eliminate the fluid– This is a condition associated with fluids administered

via the parenteral route– Signs of fluid overload includes respiratory changes,

fluid deposition in the subcutaneous space, or weight gain


Types of Colloids

• Colloid solutions are fluids with large molecules that enhance the oncotic force of blood, causing fluid to move from the interstitial and intracellular spaces into the vascular space

• Natural– Plasma– Albumin– Whole blood

• Synthetic– Dextrans– Hydroxyethyl starch– Oxypolygelatin


Fluid Additives

• Special additives can be supplemented to crystalloid solutions

• When administering additives, it is important to remember to withdraw and discard an amount of fluid equal to the amount of additive being supplemented

• Types of additives:– 50% dextrose– Potassium– Sodium bicarbonate– Calcium– Vitamins


Calculating Fluid Volumes

• Must consider that animals require fluids for the following:– Rehydration– Maintenance– Ongoing fluid loss

• Make sure the units of measure are the same when performing these calculations

• Make sure the volumes make sense; we don’t give 1,000 liters to a 4-pound cat


Calculating Fluid Volume

• Example: an adult 14-lb cat with 3% dehydration comes into the clinic; it is estimated that the cat vomited 100 ml of fluid overnight

• Maintenance fluid is the volume of fluid needed daily to maintain body function

• Maintenance fluids can be dosed at 50 ml/kg/day in adults and 110 ml/kg/day in young animals

• Step 1: convert 14 lb to kg using the conversion factor 2.2 lb = 1 kg

14 lb x 2.2 lb/kg = 6.4 kg

• Step 2: calculate maintenance volume

6.4 kg x 50 ml/kg/day = 318 ml per day




• Rehydration fluid is based on the estimated percent of dehydration % dehydration x weight in kg =

deficit in liters

• Step 1: convert 14 lb to kg using the conversion factor 2.2 lb = 1 kg14 lb x 2.2 lb/kg = 6.4 kg

• Step 2: calculate replacement for dehydration3% = 0.030.03 x 6.4 kg = 0.192 l0.192 l x 1,000 ml/l = 192 ml192 ml x 0.8 (80% of dehydration

value replaced in 24 hours) = 154 ml to replace on first day




• Ongoing fluid loss is an estimation based on the additional loss of fluid due to vomiting or diarrhea

• Take estimated volume

• Step 1: take estimated volume lost in fluid and add to the other volumes

• Final step: take all values and add together318 ml + 154 ml + 100 ml =

572 ml


How and How QuicklyIs It Given?

• Rate of fluid replacement parallels the severity of dehydration

• Ideally, fluids are given over a 24-hour period• Fluids are stored and given by fluid bags or bottles

attached to administration sets• Fluids are administered with either:

– An adult administration set that delivers 15 gtt/ml (usually)– A pediatric administration set that delivers 60 gtt/ml (usually)– See text and “Fluid & Electrolytes for Veterinary Technicians”

CD for sample calculations


Fluid Administration Using a Special Administration Chamber

• Steps for using a Special Administration Chamber– Wash hands– Follow the manufacturer’s directions for priming the

setup– Allow 10–15 mL of the fluid being administered to

flow into the chamber– Close the clamp between the bag and chamber– Clean the injection site on the administration

chamber with alcohol


Fluid Administration Using a Special Administration Chamber– Inject the medication into the chamber– Open the clamp and add the appropriate amount of fluid– Clamp the tube above the administration chamber– Gently agitate the chamber to mix the fluids– Open the clamp below the chamber– Establish the appropriate flow rate– Open the clamp above the administration chamber to

administer fluid as ordered– Chart the procedure including date, time, medication, dosage,

amount of fluid inflused, and patient’s reaction


Emergency Drugs

• In an emergency situation, it is important to remember basic life support– A = airway = establish a patent airway (endotracheal

tube, suctioning, tracheostomy) – B = breathing = provide oxygen to the patient by

providing airway or mechanical ventilation– C = circulation = get blood moving, either by manual

manipulation of the heart or by the use of drugs

• Refer to Table 19-3 of your textbook


Emergency Drugs

• The goal of emergency treatment is to maintain adequate oxygenation of vital organs

• Oxygenation of vital organs is the goal of both the respiratory and cardiovascular systems

• The primary goal of the respiratory system is to promote gas exchange

• The primary goal of the cardiovascular system is perfusion of organs and tissues


Emergency Drugs

• When making first contact with the owner of an animal that needs emergency care, obtain the following information:– Nature of the illness/injury– Condition of the animal– Time injury/event occurred– Any preexisting illness and medications– Age, breed, sex, and weight of animal, if available


19. fluid therapy and emergency drugs

Technology

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