Veterinary Fluid Therapy: Dehydration, Crystalloids, Colloids, and Shock Management

•One of the most common procedures preformed

•Supportive therapy in sick and injured patients

•Maintain blood pressure in patients undergoing surgical procedures

•60% water

Fluid Therapy

Signs of Dehydration

•Weight and temperature

•Skin turgor, decreased urine output

•Mental status

•Pulse rate and quality, blood pressure

•CRT, mucous membrane color

•Packed cell volume (PCV), total protein (TP), specific gravity of urine (>1.045), blood urea nitrogen, creatinine, electrolytes, and blood gases

mild dehydration

•Semidry MM

•Minimal loss of skin turgor

~5%

moderate dehydration

•Moderate loss of skin turgor

•Dry MM

•Weak rapid pulse

•Enophthalmos (sunken eyes)

~8%

severe dehydration

•Definite loss of skin turgor

•Tachycardia

•Extremely dry MM

•Weak or thready pulse

•Hypotension

•Altered state of consciousness

•Severe Enophthalmos

~10%

osmolality equal to blood

Isotonic

osmolality less than blood

hypotonic

osmolality greater than blood

Hypertonic

•By far the most used crystalloid

Isotonic

•Used in resuscitation, rehydration, and replacement of ongoing losses

Isotonic crystalloid Fluid

•Ex: 5% dextrose, 0.45% NaCl, Normosol-M, and

Plasmalyte 56

•Provides water in greater proportion than electrolytes

•Used to replace free water deficit and to treat hypernatremia ( high blood sodium)

•Good in patience with heart disease

•Should never be used in resuscitation

•Very ineffective for expanding vascular volume

Hypotonic crystalloid Fluid

•Osmolality greater than blood

•Ex: 3% and 7% hypertonic NaCl

•Provide electrolytes in greater proportion than water

•Shifts of fluid from the interstitium to the intravascular aids in resuscitation

•Effects only last 20 to 30 min.

•Used also to treat head trauma and traumatic brain injury

•Should not be administered faster than 0.5-1 mL/kg/minute because rapid volume expansion can cause reflex bradycardia

Hypertonic crystalloid fluid

•Contains proteins or starch molecules

•Designed to stay in the vascular space and expand volume

•Can be used for treatment of hypoproteinema

•Used when crystalloids are not effectively improving blood volume or needed for a longer duration

•Synthetic vs Natural

•Hetastarch or VetStarch

•Plasma or albumin solutions

Colloid

oliguria

Decreased urine output

Azotemia

urea in the blood

•Electrolyte solutions

•Ex: lactated ringer solution (LRS), 0.9% saline or normal saline (NaCl), Plasmalyte 148, Normosol-R

•Used in resuscitation, rehydration, and replacement of ongoing losses

Isotonic crystalloid Fluid

•Ex: 5% dextrose, 0.45% NaCl, Normosol-M, and

Plasmalyte 56

•Provides water in greater proportion than electrolytes

•Used to replace free water deficit and to treat hypernatremia ( high blood sodium)

•Good in patience with heart disease

•Should never be used in resuscitation

•Very ineffective for expanding vascular volume

Hypotonic crystalloid Fluid

•Osmolality greater than blood

•Ex: 3% and 7% hypertonic NaCl

•Provide electrolytes in greater proportion than water

•Shifts of fluid from the interstitium to the intravascular aids in resuscitation

•Effects only last 20 to 30 min.

•Used also to treat head trauma and traumatic brain injury

Should not be administered faster than 0.5-1 mL/kg/minute because rapid volume expansion can cause reflex

Hypertonic crystalloid fluid

Hypovolemic, shocky, or severely dehydrated patients

•Isotonic crystalloid fluids (LRS) IV (Shock dose)

•50-55 mL/kg cats

•80-90 mL/kg dogs

25% shock dose should be given over 10 to 15 min. For easy quick calculations the quarter shock dose is 10 mL/lb so if a patient weighs 40 lbs 400 mL will be a quarter shock dose

Dose for colloids: 10-20 mL/kg per 24 hours (typically 10 mL/kg in 2.5 to 3 mL/kg boluses) Cats

20 mL/kg/hr (divide into 5 mL/kg boluses) Dogs

Replacement requirement =

% dehydration x body weight (kg) x 10

= replacement + maintenance + ongoing losses

Daily fluid requirements

Restoring normal fluid and electrolyte status within 24 hours

Replacement Fluids

Example of replacement fluids include

Normosol-R or LRS

Maintenance rate is ______ for cats

2-3 mL/kg/hr

Maintenance rate is ______ for dogs

2-6 mL/kg/hr

Advantages Anesthesia Fluid Therapy

•Supports cardiovascular function, blood pressure, and vasodilation

•Correction of losses

•Decrease clot formation in the IV cath, may be needed in emergency

Disadvantages Anesthesia Fluid Therapy

Potential of vascular overload

low potasium

hypokalemia

Hypernatremia

high sodium

Sq fluids

peripheral circulation is poor in dehydrated and shocky patients

Absorption can take up to 6-8 hours, 50-100 mL of body temp fluids to each site

Intramedullary

not very common but useful in young patients in which quick venous access in not possible, fluids are administered directly into the bone marrow

NEVER give dextrose (sugar) under the skin

KNOW

causes water to move from the extracellular space to the intracellular space

hypotonic IV fluids

types of isotonic IV fluids

5% dextrose in water

0.9% normal saline

risks of hypotonic

cells swelling and rupture

dextrose hypotonic

in body

dextrose hypertonic

in bag

hypoglycemic patients clinical signs

weakness, seizures, ataxia, collapse, stupor, muscle tremors

xylitol

in gum

ataxia

cant walk

how to administer dextrose for hypoglycemic patients

dilute 1:1 with salime

how to calculate dextrose solution

c1xV1=c2Xv2

used to treat metabolic acidosis

bicarbonate

brown port is for

blood