Fluids Flashcards
Colloid Fluid
Synthetic Fluids with large molecules suspended in isotonic crystalloid solution.
The large molecules of colloids remain in the vascular space, providing sustained volume expansion via oncotic pressure.
These tend to be very efficient for resuscitation after large volume losses due to bleeding and injury.
Oncotic Pressure
Pressure exerted on capillary walls by plasma proteins
Crystalloid Fluid
electrolytes dissolved in water.
capable of passing through cell membranes
can enter all body fluid compartments
contain electrolytes and other substances
three types- hyper, hyop and is
Circulating blood volume of a horse
80 ml/kg of body weight
Percent of fluid in body
60%
Extracellular fluid
consists of interstitial and intravascular fluid. It is fluid that is not contained in cells. It is found in blood, in lymph, in body cavities lined with serous (moisture-exuding) membrane, etc
approximately 20% of body weight
Hypotonic crystalloids
Osmolality lower than that of blood and provides water in greater proportion than electrolytes.
Hydrates ECF
Rapid redistribution within the total body water (TBW).
Examples of hypotonic crystalloids
5% dextrose in water (D5W),
0.45% NaCl (½ the strength of normal saline),
0.45% NaCl with 2.5% dextrose (½ and ½).
Uses of hypotonic crystalloids
To replace free water loss
maintenance fluid therapy
Useful for patients with end-stage renal or heart failure, as they contain lower sodium concentrations
hypernatremia
Hypernatremia is the medical term used to describe having too much sodium in the blood. (ie, not enough water)
never used for fluid resuscitation from shock because they don’t expand the intravascular volume well.
hypotonic crystalloids
Isotonic Crystalloids
have an osmolality equal to that of blood.
They’re used to replace water and electrolytes and are primarily distributed to the extracellular space.
Isotonic solutions are commonly used for rehydration and shock resuscitation.
** less important: After administration of a crystalloid bolus, 65–75 percent of it will leave the intravascular space and redistribute to the interstitial space within 30 minutes.
Intravascular space
The space contained within blood vessels. The main intravascular fluid is blood.
(25% of ECF or 8% of TBW).
Interstitial space
Interstitial space refers to the fluid-filled spaces between blood vessels
(75% of ECF or 25% of TBW)
Examples of isotonic solutions are
normal saline (0.9% sodium chloride in water),
lactated Ringer’s,
balanced electrolyte solutions such as Normosol-R.
Hypertonic crystalloids
have an osmolality greater than that of blood.
Expand plasma volume
Used in traumatic brain injury to move fluid out of the interstitial spaces of the brain to cause a decrease in intracranial pressure
Concerns regarding colloid use
Concerns regarding colloid use in humans are the ability to cause coagulopathy and acute kidney injury. However, these haven’t been documented as a concern in veterinary medicine.
Examples of colloids
VetStarch and Hetastarch.
Patients with hypokalemia can receive what additive?
potassium chloride or potassium phosphates
Patients with hypoglycemia can receive what additive?
dextrose can be added to balanced electrolytes for a final concentration of 2.5 to 10 percent.
sodium bicarbonate fluids
Generally recommended against. Use only in extreme cases of a blood pH of less than 7.1 to help restore acid-base balance. Need to find the real cause of the imbalance
Resuscitation Phase Fluid therapy
Intended to restore volume loss in hypovolemia and shock.
With resuscitation therapy, a fraction of the shock dose is given over a short period, and then the patient is monitored for the response.
the fluid amounts are given based on patient clinical response.
Which fluids are used for resuscitation phase
Hypertonic crystalloids and colloids
Replacement Phase fluid therapy
Intended to replace lost body fluids and electrolytes. Correction of dehydration can be estimated with a simple calculation. However, the animal’s condition (age, health state, nutritional status) must also be considered to avoid inappropriate volume administration.
Fluids used during replacement phase
Isotonic solutions such as lactated Ringer’s solution are often used for replacement therapy
Fluid deficit calculation:
Bodyweight (kg) × % dehydration = volume (L)
Minimal loss of skin turgor, mucous membranes are moderately dry, eyes are normal.
Mild (5%) dehydration
Moderate loss of skin turgor, dry mucous membranes, pulse is weak and rapid, enophthalmos observed.
Moderate (8%) dehydration
Significant loss of skin turgor, presence of tachycardia, weak pulse and hypotension, considerable dryness of the mucous membranes, severe enophthalmos, central nervous system effects
Severe (10%) dehydration
normal hydration
euhydration
Goal of replacement phase of fluid therapy
restore euhydration within 24 hours of initiating fluid therapy.
When calculating fluid deficit: Edit
The deficit and ongoing losses must be added to maintenance volumes. Ongoing losses are replaced within 2 hours of loss, while deficit volumes are replaced over longer periods of time.
Maintenance Phase of fluid therapy
When hydration is restored, and there are no ongoing fluid losses, the patient can be provided maintenance fluids. This is done if the patient still can’t take in fluids normally.
Maintenance fluid, fluid requirement
- Dogs: 2–6 mL/kg/h
- Cats: 2–3 mL/kg/h
Circulating blood volume
Dogs- 80 to 90 mL/kg
cats - 40 to 60 mL/kg,
horses - 80 mL/kg, .
allometric scaling
Correlates the mass of an animal with physiological parameters through an exponent, ¾.
The most common indications for blood or plasma transfusions are as follows:
Blood loss
Coagulopathy
Anemias
Patients with active bleeding due to thrombocytopenia or thrombocytopathia
Decrease in total plasma protein concentration
Failure of transfer of passive immunity in neonates
Hypoalbuminemia
Cat and dog blood donors
between 1 and 7 years old
Be over 25 kgs for a dog and 5 kgs for a cat
They’re tested for the presence of bloodborne disease and receive routine medication only for common parasites.
Horse blood donors
must be over 450 kgs
Equine donors must test negative for equine infectious anemia and have up-to-date vaccinations.
cross-matching
detects agglutination reactions between the donor’s red blood cells (RBCs) and the recipient’s plasma.
agglutination
Visible or microscopic irregular, variably sized clumping of red blood cells (RBCs) that form because of excess antibodies bound to the surface of RBCs.
Rouleaux formation
Rouleaux formation refers to red blood cells (RBCs) in chains that resemble a stack of coins.
In horses and cats, rouleaux formation is common, whereas in dogs, rouleaux formation may be an indication of inflammation or an artifact of smear preparation.
Initial rate of blood transfusion
Blood is initially given at a rate of 0.3mL/kg over the first 20 to 30 minutes,
To prevent RBC deterioration, blood is______ and then ______ for the hypothermic patient
Refrigerated
warmed to room temperature for
Osmotic pressure.
The ability of the particle to attract water across a membrane is called
hypertonic solution precautions
- giving too fast may cause serious side effects.
- Hypertonic saline should be infused through a well-secured intravenous catheter to prevent extravasation of irritating fluids.
If you’re giving the fluids too quickly and overhydrating the patient, you may see any of the following signs:
Restlessness
Clear nasal discharge
Crackles when you listen to lungs with a stethoscope
Tachycardia
Dyspnea
Other unfamiliar signs
insensible loss
loss of fluid that can’t be measured like respiration
estimated at one-third of maintenance requirements.
