Transcript VTHT1441Chapter2pptPt2

CHAPTER 2 Part 2
PATIENT PREPARATION
 IV CATHETERS: catheters are ideal for all anesthetic
procedures
 Can provide IV fluids for support during surgery (blood loss,
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dehydration, prevent/treat hypotension)
Allows injection of medications such as antibiotics and
analgesics and allows constant-rate-infusions
Provides access to a vein in an emergency (cardiac arrest,
seizures ). Do not remove until animal is fully awake!
Allows irritating agents to be injected (ex: thiopental)
Allows injection of incompatible drugs
PATIENT PREPARATION
 IV CATHETERS: Choose catheter size based on patient’s size
and need
 Risks with catheter placement:
 AIR- always remove air from IV line before connecting to
patient
 BROKEN TIP- don’t repeatedly advance and retract the stylet
 OVERHYDRATION- can avoid by using infusion pump or
calculate drips/sec
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signs of over-hydration: eye/nose discharge, swelling of conjunctiva,
SQ edema, increased lung sounds and respiration rate, dyspnea,
coughing, restlessness, hemodilution
 SEPSIS- wipe area of catheter placement with an antiseptic and
injection ports with alcohol
 HASTY INJECTION OF DRUGS – Just because the catheter is
there, doesn’t mean all drugs should be given IV
PATIENT PREPARATION
 IV FLUIDS: the patient’s infusion rate will depend on
body weight and procedure
 Fluids during surgery/anesthesia:
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5-10 mL/kg/hr (10mL/kg/hr is typical for the 1st hour,
then reduced to 5mL/kg/hr for the remainder of the
procedure)
 intended to compensate for vasodilation and fluid loss during
anesthesia/surgery
 Isotonic, polyionic replacement crystalloids are the
first choice for fluid therapy in healthy patients.
PATIENT PREPARATION
 IV FLUIDS: fluid rates can be adjusted for those
patients that are compromised
 CV disease
 Respiratory disease
 Fluid rates for these patients are often dropped to
5ml/kg/hr
 An animal with excessive hemorrhage or low blood
pressure during surgery can have fluid rates increased
 Dogs: up to 40mL/kg/hr for max of 1 hour
 Cats: up to 20ml/kg/hr for max of 1 hour
 A quick way to estimate amount of fluids to give:*Give
~3mL of fluid for every 1mL of blood loss
PATIENT PREPARATION
 ANIMALS IN SHOCK: these patients need even more
rapid fluid rates
 Dogs: 50-90mL/kg/hr
 Cats: 40-60mL/kg/hr
 ¼ of the calculated dose is given and then patient re-
evaluated (a 10-20mL/kg bolus)
 Animals in shock may show the following signs:
 Pale mucous membranes
 Low blood pressure
 Slow heart rate
PATIENT PREPARATION
 IV FLUIDS: drip sets (administration sets) help
determine how fast the fluids are administered
 Patients greater than 10kg use a macrodrip set
 Macrodrip sets are either 10gtt/mL or 15gtt/mL
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VTI has 15gtt/mL sets
 Patients less than 10kg use a microdrop set
 Microdrip sets are 60gtt/mL
PATIENT PREPARATION
 IV FLUID ADMINISTRATION SETS
MACRO
MICRO
PATIENT PREPARATION
 IV FLUID ADMINISTRATION: most clinics have an IV
fluid pump. The pump controls how many drops of
fluid are delivered to the patient over a period of time.
 If no pump is available, the anesthetist will need to
calculate how many drops of fluid should be
administered to the patient in a period of time as well as
monitor the fluids closely.
PATIENT PREPARATION
MATH
 Step 1: Obtain the patient’s weight in kgs.
 If the patient’s weight was obtained in pounds, then you must
divide by 2.2
 Step 2: REMEMBER THE SURGICAL FLUID RATE:
10mL/kg/hr. Multiply the patient’s weight in kgs by 10. This
will give you how many mLs the patient should receive in 1
hour known as the infusion rate.
 Step 3: Determine the drip set necessary for the patient based
on weight.
 Step 4: Multiply the patient’s infusion rate by the drip set.
 Step 5: Divide the number from Step 4 by 3600 (because
there are 3600 seconds in 1 hour). THIS FINAL ANSWER
WILL TELL YOU HOW MANY DROPS OF FLUID EACH
SECOND THE PATIENT WILL RECEIVE WHILE UNDER
ANESTHESIA.
PATIENT PREPARATION
 Patient weighs 6 kg.
 Surgical fluid rate is 10mL/kg/hr: 6 x 10 = 60 mL/hr
 Patient needs microdrip set: 60 x 60 = 3600
 3600/3600 = 1 drop/sec
 Patient weighs 12 kg.
 Surgical fluid rate is 10mL/kg/hr: 10 x 12 = 120 mL/hr
 Patient needs a macrodrip set: 120 x 15 = 1800
 1800/3600 = 0.5 drops/sec
 0.5 drops/sec is impossible to count, but if we multiply by 10
it will tell us how many drops to administer in 10 seconds
 0.5 x 10 = 5 drops/10 sec
PATIENT PREPARATION:Fluid
Administration
•Body fluids consist of
water and solutes.
•Water is 60% of
body weight.
•It is divided into
ICF and ECF
(fluid in the
vessels and fluid
between the
cells)
•The other 40% is
solutes
PATIENT PREPARATION
 FLUID ADMINISTRATION
 Body fluid solutes:
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ions
large plasma proteins or colloids,
small nonionic particles such as glucose and small proteins
Electrolytes:
Cations
+
 Sodium (Na )
+
 Potassium (K )
2+
 Magnesium (Mg )
2+
 Calcium (Ca )
Anions
 Chloride (Cl−)
 Bicarbonate (HCO3−)
 Phosphates (HPO42− and H2PO4−)
 Proteins
PATIENT PREPARATION
 OSMOLARITY is the solute concentration maintained
in all body fluids. It is 300 mOsm/L
 PRINCIPLES OF WATER AND SOLUTE BALANCE:
 One-third of IV fluids administered will stay in the
intravascular space. Two-thirds will diffuse into the
interstitial space.
 Colloids don’t pass freely through the vascular
endothelium.
 The presence of colloids in the intravascular space draws
water into the space creating osmotic or oncotic pressure.
 Some solute concentrations (Ca2+, K+) must be kept
within a narrow range to maintain normal heart and
muscle function.
PATIENT PREPARATION
 FLUID ADMINISTRATION FOR ANESTHETIZED
PATIENTS
 Anesthetic agents affect cardiopulmonary function by
decreasing inotropy and heart rate. Many agents also
cause vasodilation. This results in an overall decrease in
cardiac output and hypotension.
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This affects oxygen delivery to the tissues
IV fluids increase circulating blood volume and cardiac
output
PATIENT PREPARATION
 REVIEW OF IV FLUID TYPES: Crystalloids vs. Colloids
 CRYSTALLOIDS: the most common fluid type. Used for
fluid replacement and maintenance. The 3 general
categories of crystalloids are:
 Balanced electrolyte solutions (isotonic, polyionic,
replacement solutions)
 Saline solutions
 Dextrose solutions
PATIENT PREPARATION
 CRYSTALLOIDS: BALANCED ELECTROLYTE
SOLUTIONS
 Contain a solute profile similar to the extracellular
fluid since dehydration and many general diseases
and peri-operative hemorrhage deplete the ECF
first.
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This means higher concentrations of Na+ and ClExamples: Plasmalyte, Normosol, Lactated Ringer’s
PATIENT PREPARATION
 CRYSTALLOIDS: SALINE SOLUTIONS
 Contain ONLY Na+ and Cl Examples: Normal Saline & hypertonic Saline
 Normal Saline (0.9%): used to flush body cavities,
flush catheters, blood transfusions
 Hypertonic Saline (3%, 5%, 7%): very concentrated
and quickly draws water into the intravascular space
and supports blood pressure, but rapidly diffuses out
into the interstitial space. Used for profound
hemorrhage, shock, increased intracranial pressure
PATIENT PREPARATION
 CRYSTALLOIDS: DEXTROSE SOLUTIONS (2.5%,
5%)
 Used in cases of hypoglycemia, neonatal,
debilitated animals, hyperkalemia, patients
receiving insulin
 Don’t use as the sole fluid. The sugar is rapidly
metabolized to CO2 and water. The free water
diffuses out into the interstitial space.
PATIENT PREPARATION
 COLLOIDS: large molecules that do not readily leave
the intravascular space
 These are helpful in maintaining blood volume and
pressure
 Less side effects than hypertonic saline
 Rapidly pulls water into the intravascular space
 Examples: Plasma or blood, synthetic colloids, blood
substitutes
PATIENT PREPARATION
 COLLOIDS: PLASMA OR BLOOD
 Contains albumin, clotting factors, globulins
 Used in animals with acute blood loss, anemia,
hypoproteinemia
 Expensive
 COLLOIDS: BLOOD SUBSTITUTES
 Used for acute hemorrhage and anemias
 Oxyglobin contains hemoglobin molecules of bovine origin
similar to red blood cells that are able to carry oxygen.
 The benefit is that there is no cross-match required
 THIS PRODUCT IS NOT CURRENTLY AVAILABLE
PATIENT PREPARATION
 COLLOIDS: SYNTHETIC COLLOIDS (Hetastarch,
Dextran)
 More readily available than blood products
 Less expensive and longer shelf life than blood
products
 Used in cases of shock, hypoproteinemia
 Usually administered IV at rate of 1020mL/kg/day; bolusedslowly over 15-60 minutes
PATIENT PREPARATION
 ADVERSE EFFECTS OF FLUID ADMINISTRATION
 Volume overload – more likely in patients that are <5kg or
those with cardiac or renal disease *reduce infusion rates
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Ocular/nasal discharge
Chemosis
Subcutaneous edema
Increased lung sounds
Increased respiratory rate
Dyspnea
Coughing, restlessness
 Hemodilution – dilution of the RBC’s and plasma proteins.