Introduction to Anesthesia Flashcards
Desirable properties of anesthesia and/or chemical restraint
convenient, safe, effective restraint that is inexpensive
with minimal stress, pain, discomfort, and toxic side effects
General anesthesia
a reversible state of unconsciousness, immobility, muscle relaxation, and loss of sensation produced by the administration of one or more anesthetic agents
Surgical anesthesia
stage of general anesthesia in which there is sufficient analgesia and muscle relaxation to allow surgery to be performed without patient pain/movement
Analgesia
loss of sensitivity to pain
Sedation
drug-induced CNS depression and drowsiness that varies in intensity from light to deep
Tranquilization
drug-induced state of calm in which the patient is reluctant to move and is aware of but unconcerned about its surroundings
Hypnosis
sleep-like state in which the patient can be aroused with sufficient stimulation
Narcosis
drug-induced sleep from which the patient is not easily aroused, usually associated with the administration of narcotics
Local anesthesia
loss of sensation in a small area of the body produced by the administration of a local anesthetic agent
Topical anesthesia
loss of sensation of a localized area produced by the administration of a local anesthetic directly to a body surface
Regional anesthesia
Loss of sensation in a limited region of the body produced by administration of an agent in proximity to sensory nerves
Types of Anesthesia
by route of administration
IM/SQ IV Inhalation Infiltration Field block Regional nerve block Topical Rectal Epidural/Spinal Intratesticular Oral Acupuncture
veins used for IV anesthesia in the dog/cat
Cephalic
Jugular
Saphenous/Femoral
veins used for IV anesthetic in the horse/cow/goat/sheep
Jugular
Coccygeal v. (cow – not common)
period to withhold food in adult dogs/cats
12 hours, water 2 hours
period to withold food in puppies/kittens < 3 months, toy breed dogs < 10 lbs, birds, pocket pets
short to no fast
period to withhold food in horses
4-8 hours , do not withhold water
period to withhold food in pigs
adults 8-12 hours, neonates 1-3 hours, do not withhold water
period to withhold foot in large ruminants
12-36 hours, water 8-12 hours
period to withhold food in small ruminants
12-24 hours, do not withhold water
period to withhold food in calves, lambs, kids
2-4 hours
reasons for IV catheterization
Easy administration of IV anesthetics
Good route for emergency drugs
Fluid therapy during surgery/recovery
Transfusion therapy prn
routes of IV catherization
Dog – cephalic, jugular, saphenous v. Cat – cephalic, jugular, femoral v. Horse, Cow, Sheep – Jugular v. Pig – Ear veins Rabbit – Ear veins Neonates – Medullary cavity
risks of IV catheterization
Air embolism
Accidental over-hydration
signs of accidental overhydration
ocular/nasal discharge; chemosis (edema/swelling of conjunctiva); increased lung sounds; increased respiratory rate; dyspnea)
maintainence fluid administration rate for dogs
2 mL/kg/hr OR 30-45 ml/lb/24 hours
maintainence fluid administration rate for small dogs/cats
4 ml/kg/hr OR 30-45 ml/lb/24 hours
dehydration deficit
% dehydration X wt (kg) X 1000 = mL deficit
Replace ½ over 4-8 hr; remainder over rest of 24 hr. period
fluid administration rate during anesthesia
2-10 mL/lb/hr with 5 mL/lb/hr most common
fluids to replace blood loss
3 mL fluid/1 mL blood loss
Total blood volume = 40 mL/lb
If PCV > 20%; TP > 3.5 mg/dL
blood to replace blood loss
If > 30% blood volume lost acutely If PCV < 15% - chronic anemia Administer 1mL blood/mL lost acutely One 3X3 gauze sponge holds 5-6 mL If donor PCV 40%, 1mL whole blood/lb raises PCV 1% in recipient
rapid rehydration fluid administration rate for healthy dogs
40 mL/kg for 1 hr. w/ ½ in first 15 min.
Must then slow IV flow rates
rapid rehydration fluid administration rate for cats
20 mL/kg for 1 hr.
Must then slow IV flow rates
shock therapy fluid administration rate for dogs
Up to 90 mL/kg/hr max (40 mL/lb/hr)
shock therapy fluid administration rate for cats
50-70 mL/kg/hr
crystalloid IV fluid (water-based)
Normal saline – 0.9% NaCl
Hypertonic saline – 3, 5, or 7% - For shock therapy, May give 3 mL/lb IV of 7%
Lactated Ringer’s (LRS) - Balanced electrolytes Na, Cl, K, Ca
Dextrose in water or added to saline or LRS - 2.5% or 5%
colloid IV fluid
Not water based; higher specific gravity; contain molecules which do not cross vessel walls
Plasma or blood
Synthetic - Dextran, Hetastarch - Remain in circulation – draw fluids
Blood substitutes - Oxyglobin, etc. - Contraindicated with renal or cardiac impairment
