Fluid Therapy & Emergency Drugs

Describe body fluid composition, location, and % in animals.

homeostasis - stable state that keeps the physical/chemical properties of body fluid constant water is the primary body fluid intracellular - within cells intravascular - within blood vessels interstitial - between cells + blood vessels

intracellular fluid (ICF) - fluid within cells 2/3 of body water; skeletal muscle, blood/bone cells, adipose extracellular fluid (ECF) - intravascular + interstitial 1/3 of body water; plasma + interstitial fluid

In healthy animals, H2O in = H2O out fluid intake = liquids and food fluid loss - urinary, GI, resp, and skin losses kidneys - primary regulator

fluid balance depends on electrolyte balance when fluid volume changes = electrolyte concentration changes primary ions = sodium, potassium, chloride, phosphate, and bicarbonate

Describe level of dehydration based on physical findings.

normal, healthy animals = fluid and electrolytes are balanced sick animals = balance is disrupted (fluid therapy is necessary)

60% body weight = water 80% neonate body weight = water 1L H2O = 1kg 100lb dog (45kg) = 27kg H2O

Basis for fluid therapy rests on the animal’s hydration status. Can be determined by assessing the patient’s history, physical exam status, and laboratory findings.

patient history body weight skin turgor pulse rate & quality CRT mucous membranes sunken eyes total protein PCV Urine SG Hydration status on PE

vomiting or diarrhea, no abnormalities on PE = <5% dry mucous membranes = 5% mild/moderate decrease in skin turgor, dry membranes, tachycardia = 6-8% marked decrease in skin turgor, dry membranes, tachycardia, slow CRT, sunken eyes, CNS depression = % Level of Dehydration

Describe routes of fluid administration.

oral (PO) - short term illness, small animals, neonates routes = stomach tube, dosing syringe, bottle, nasogastric tube, gastrostomy tube adv- safest disadvantages = possible aspiration pneumonia, can’t use in vomiting animals, slow absorption

subcutaneous (SQ) = mild to moderate dehydration in non-critically ill patients routes = 18-20g needle in flank or dorsally between scapulae; 5-10 mls of fluid per lb body weight disadvantages = limited volume, infection, SQ edema, slower absorption, unable to use irritating solutions

intravenous (IV) = moderate to severe dehydration and hypovolemic patients routes = admin of IV catheter using aseptic technique adv- rapid delivery disadvantages = fluid overload, injury to blood vessels, extravascular placement of fluids, close monitoring

intraperitoneal (IP) = IV access unavailable routes = 16-20g needle in aseptic injection site; just lateral to ventral midline between umbilicus and pelvis adv - rapid absorption disadvantages = sepsis, no abdominal surgery patients, no hypertonic solutions

intraosseous (IO) = small animals, birds, pocket pets routes = via bone marrow using sterile technique; needle proportionally sized to bone (humerus + femur) adv - direct access to vascular space disadvantages = not practiced often, bone infection, must avoid growth plates

rectal (pr) = young animals absorption is good and rapid not used often can’t use with diarrhea

Types of fluids & additives

1. crystalloids - sodium based electrolyte solutions used to replace lost fluids; similar to plasma fluid isotonic - same osmolality of blood and ECF hypotonic - lower osmolality than blood hypertonic - higher osmolality than blood

isotonic examples 0.9% sodium chloride (saline) lactated ringers solution (LRS) Normosol Plasmalyte

Isotonic saline (0.9% sodium choride) only sodium and chloride ions expands plasma volume corrects decreased sodium levels should not be used in patients with heart failure

Lactated Ringers Solution saline and lactate solution with added electrolytes (Na, K, Cl, Ca, and lactate) helpful in treatment of acidosis (cellular breakdown due to severe dehydration)

Normosol solution with less Na, more K, more Mg, less Cl, no Ca all purpose replacement fluid

Plasmalyte solution with less Cl, more Mg, no Ca cannot be given SQ as it irritates tissues

2. Colloids - fluids with large molecules that cause fluid to move from interstitial/intracellular space into vascular space cannot diffuse across cell membranes natural - plasma, albumin, and whole blood synthetic - dextrans, oxypolygelatin

whole blood treatment of severe anemia and severe blood loss contains all cellular components of blood blood group typing and testing for infectious diseases is recommended

plasma contains albumin and other important proteins restores body protein

Dextran - synthetic colloid solution contains large polysaccharides derived from sugar beets treats cases of shock

Hetastarch - synthetic colloid that expands plasma volume combination of hydroxyethyl starch and normal saline treats hypovolemic shock and hypoproteinemia

additives - used to improve patient recovery; crystalloids 50% dextrose - hypoglycemic patients; serves as energy source for brain potassium - anorexic or diuretic patients; avoids cardiac problems sodium bicarbonate - patients with acidosis; lowers acidity

calcium - hypocalcemia patients; supplement for milk fever, etc. vitamins - anorexic or debilitated animals; C and B complex (water soluble)

Calculating fluid therapy

Fluid is required for: rehydration - to correct loss due to dehydration maintenance - to replace loss due to normal body functions replacement - to replace loss due to vomiting and diarrhea (ongoing fluid loss)

Dehydration affects younger animals more rapidly older patients with chronic disease require more fluids active animals or those in hot/humid conditions need more fluids corticosteroids and diuretics alter fluid requirements

Rehydration Based on the estimated % dehydration ml = % dehydration x weight (kg) x 1000 ex: 0.10 x 12.5kg x 1000 = 1,250 ml (this will always be added to the maintenance volume)

Maintenance Losses from feces and urine are easily measured; sweating, ventilation, and evaporation are not. 50 ml/kg/day in adults 110 ml/kg/day in young animals ex: 50 ml x 12.5 kg x 1 day = 625 ml

Replacement determined by estimation closely monitor the animal 500 mls of fluid loss due to vomiting = 500 mls replacement + maintenance/rehydration volume

How rapidly do we give fluids? Rapidly at first, then tapered to maintenance. Depends on CV and renal status. Ideally given over 24 hours. Veterinarian always dictates.

Fluid administration sets deliver drops/ml of fluid. Adult admin sets = 15 gtt/ml Pediatric = 20 gtt/ml Always check individual sets as they vary.

An adult dog needs 1,136 ml/day 1,136 ml/24hrs x 15 gtt/ml = 17,040 gtt/24hrs 17,040 gtt/24hrs x 1hr/60min = 11.8 gtt/min (round to 12) 12 gtt/min = 6 gtt/30sec = 3 gtt/15 sec = 1gtt/5 sec (make it easier to count)

Administration sets and delivery systems

Fluid bags & bottles deliver fluids by gravity rate is adjusted by the diameter of the administration line roller clamps adjust to increase/decrease the amount of fluid delivered screw or slide clamps may adjust the line diameter

Infusion pumps machines on which flow rates are set and total amount to be given is entered can be readjusted as needed

Indicators of too much fluid increased serous secretions tachycardia harsh lung sounds restlessness

CPR and Respiratory Distress

CPR - cardiopulmonary resuscitation used to restore breathing and heartbeat unconscious animals only

Establish a clear airway Lay animal on its right side. Tilt back head, extend neck and pull tongue between front teeth. Suction may be used if needed. Endotracheal tubes or tracheostomy may be used if needed. Airway

Breathing Endotracheal tubes will deliver 100% oxygen. Manual resuscitators (AmbuBags) deliver 21% oxygen. Mouth to tube delivery is 17% oxygen.

Small dogs/puppies/cats - cover and seal entire snout and exhale until chest rises. Med/large dogs - hold muzzle closed, place mouth over nostrils and exhale until chest rises Give 4-5 rapid breaths and check for breathing. Manual Respiration

Circulation External cardiac compressions should begin if no pulse. Lie with animal facing you. Place palm over ribs where elbow touches chest. (5th intercostal space) Other hand placed under chest for small dogs/cats; placed over hand for med/lg dogs

Compress 1/2 - 1 inch for small dogs/cats. Compress 1-3 inches for med/lg dogs. Large dog = 1b - 10c Med dog = 1b - 5c Sm dog/cat = 1b - (3-5)c Continue for 20 minutes or until assistance.

epinephrine - no heartbeat ( mg/kg IV) atropine - slow heartbeat ( mg/kg IV) mannitol - prolonged CPR or unconscious (250 mg/kg IV) Emergency Drugs