W2 (2) Flashcards
Oncotic pressure
Colloids presence in the vascular space provides colloid osmotic pressure
Describe the body as a closed system
Any fluid lost must come from either the ICF or the ECF
Example: If an animal is hemorrhaging
- Fluid is lost from the intravascular space (plasma)
- Cells are lost from the ICF (red and white blood cells)
Addition to losses : Fluid can and does move between compartments dynamically and changing fashion to maintain equilibrium
- Technician’s responsibility : Keep in mind which compartment needs to be replenished and what needs to corrected
Why would you administer fluid
- Correction of dehydration
- Expansion and support of intravascular vole
- Correction of electrolyte disturbances (Sodium (Na+), Chloride (Cl-), Potassium (K+), Magnesium (Mg++), Calcium (Ca++), Phosphate (HPO4–), Bicarbonate (HCO3-))
- Ensure appropriate redistribution of fluids that may be in the incorrect compartment
Oliguria
The production of abnormally small amounts of urine
Hypovolemia
The loss of fluid in the intravascular space
Compare dehydration to hypovolemia
Dehydration - The water deficit in the interstitial and intracellular compartments
Hypovolemia - The loss of fluid in the intravascular space
How to assess hydration status in a patient
- Skin tent test (turgor)
- mucous membrane moisture
- Oliguria
- Increased packed cell and total protein levels
Administration of blood products vs hypertonic saline vs blood plasma
- Administration of blood products : To provide RBC’s or hemoglobin to support oxygen carrying capacity, Clotting factors and platelets to support clotting (normal coagulation)
- Administration of hypertonic saline or colloid solutions : To draw water into the vascular space and raise the blood pressure
- Administration colloids or blood plasma (fluid containing large solutes) : Remain longer in the vascular space, Maintain blood pressure and volume
Routes of administration of Fluids
Intravenous (IV) Route
Intraosseus (IO) Route - Catheter in the medullary cavity of a bone
What is a characteristic of all IV fluids?
All intravenous fluid are solutions
- Contain one or more solutes dissolved in water
- Most contain one or more electrolyte
- Some may contain Dextrose (form of glucose)
- Some may contain buffers : Lactate, gluconate;Acetate (liver converts in sodium bicarbonate / Help regulate pH)
- Some may contain colloids : Larger solutes
How are fluids classified
Classified based on their molecular weight and solutes the solution contains
Crystalloid vs colloid classifications
Classified by: Mix and quantity of solutes, Replacement or maintenance fluids, Isotonic, hypotonic, or hypertonic
- Replacement Fluids have high concentrations of sodium and chloride : Designed to replace fluid losses
- Maintenance Fluids have lower concentrations of sodium and chloride, but also more Potassium : Designed to maintain fluid balance of a period of time
Isotonic fluids
Have an osmolarity near to blood plasma
Hypotonic and hypertonic fluids
Have an osmolarity either lower or higher than plasma
Characteristics of crystalloid solutions
Contain water and small weight solutes (electroyltes, dextrose, buffers)
Types of Crystalloid solutions
Isotonic replacement solutions, Isotonic maintenance solutions, Normal saline solutions, Hypertonic Saline solution s
Isotonic Replacement solutions
Lactated Ringer’s Solution (LRS) - has calcium, no magnesium
Plasma-Lyte A (PLA) - has magnesium, no calcium
Plasma-Lyte 148 (PL148) - has magnesium, no calcium
Normosol-R (NR) - No calcium, has magnesium
Isotonic maintenance solutions
For maintenance fluid therapy over a longer period of time; reflects the solute composition of total body water
- Normosol-M (NM%) / Plasma-Lyte 56 in 5% dextrose (PL5) - both solutions have less sodium and chloride and more potassium
Normal saline solutions
AKA - Physiologic saline, 0.9% saline, or sodium chorlide 0.9% normal saline solution (NS)
- contains only sodium and chloride ions in water
- an unbalanced replacement solution
- Used in : Addison’s disease, Administering blood transfusions, Bathe exposed tissue or body cavities during surgery, Flush intravenous catheters (+/- heparin)
- does not contain any potassium and can cause hypokalemia (need potassium supplement)
Hypertonic saline solutions
- Highly concentrated solutions (3%,7%…)
- Treat patients with hypovolemic, traumatic, or endotoxin shock
- Rapidly draws water into the intravascular space and supports blood pressure ( rapidly diffuses into the intersititial space
Dextrose solutions
Contains dextrose as the only solute in the solution
- Are available on the market or can be mixed in house (2.5% or 5% solutions)
- Not usually used for replacement fluid therapy
- Used for specific purposes : Support blood glucose in neonates, hypoglycemic or debilitated patients, diabetic patients
Characteristics of colloid solutions
Are larger molecular weight solutes that do not freely diffuse across the vascular endothelium
- Stay in the intravascular space
- Support expansion of blood volume and blood pressure
- Two basic types of colloids : Synthetic and blood product
Why are fluid rates high? compensating?
For anesthesia the fluid rates are higher than the volume required to maintain hydration in the patient and compensate for:
- Vasodilation
- Decreased cardiac output
- Increased insensible fluid loss (loss of fluid through skin, respiratory tract, feces)
Volume overload
Fluid Administration too rapid can result in volume overload –>Pulmonary edema / Cerebral edema
All patients under anesthesia must be monitored for signs over hydration!
(esp Patients under 5 kg (10 lbs.), Renal disease, Cardiopulmonary disease)
Signs of over hydration
- Ocular and nasal discharge
- Edema and swelling of the conjunctiva
- Subcutaneous edema
- Increased lung sounds (wetness)
- Increased respiratory rate
- Dyspnea (difficult or labored breathing)
How to avoid over hydration
- Good monitoring techniques!
- Administer fluids via fluid pump or monitor fluid bag carefully (Fluid bag should be labeled with a time and volume scale for every hour)
- Use of a burette for smaller patients
What are the duties of the Tech during the preanesthetic period?
During the preanesthetic period, the technician has many duties. He or she must help the attending veterinarian develop a minimum patient database, ensure that fasting instructions were followed, place an intravenous (IV) catheter, administer fluids, stabilize the patient, prepare equipment, and administer medications
How important is the patient history
An accurate and complete patient history is at least as important, if not more important, than results of diagnostic tests in shaping patient management prior to anesthesia
What are some conditions and diseases that require treatment and impact anesthetic management
Dehydration, anemia, abnormal bleeding, respiratory or cardiovascular system disease, kidney or liver dysfunction, and conditions that require treatment while the patient is under anesthesia are physical findings that may influence anesthetic management
What is the physical Status Classification?
This system is used to assess the patient’s overall health preoperatively by placing the patient into one of five grades ranging from a normal, healthy patient (class PS1) to one that is moribund and not expected to survive without the surgery (class PS5).
What are factors that play into the selection of anesthesia
Established protocols in the clinic : Veterinary Technician is familiar with the protocol, Remember to evaluate each patient on individual bases, The veterinarian bears responsibility for the patient and must make the final decision regarding the anesthetic protocol
- Facilities and Equipment
- Familiar with the anesthetic agents : It is not advisable to anesthetize a high-risk patient with a new combination of drugs that the anesthetist may have heard or read about but has never tried before
- Type of Procedures : Procedures vary in their duration and complexity. Require different degrees of analgesia, immobilization, muscle relaxation, and CNS depression
- Cost
- Degree of Urgency : Critically injured patients, Rapid blood loss, shock, chest or abdominal injury –> Selection of agents that allow preservation of adequate blood pressure and rapid induction to place the patient under anesthesia
