Patient Preparation (Part 1)
Role of the Veterinary Anesthetist
MPD (minimum patient database); proper pt fasting; preinduction pt care; all supplies are available; all equipment is in working order; preanesthetic medication
Why is communication important?
Makes clients feel more comfortable/less anxious; clients are more confident in your work; shows you care; informed client can better handle unexpected results.
Components of an MPD
Pt Hx--including signalment, PE (exam), PA (assessment), and a preanesthetic diagnostic workup
How and why do you confirm the scheduled procedure?
Verbally; prevents tragic accidents; know the specifics (exact location of tumors, owner's wishes re: cytology/histology, decisions during the procedure)
Anesthetizing the wrong pt; performing an unnecessary procedure; not performing a scheduled procedure
Patient Hx is info
obtained from the client; determine the following: info given freely, duration, severity/volume, frequency, appearance/character
What types of questions do you ask?
Not those that can be answered w/yes or no; not leading questions.
Components of Signalment
Breed, reproductive (status), age, sex, species ("BRASS")
Signalment: Species: Horses & cats are more sensitive to
opioids; use w/caution @ lower doses or don't use at all
Signalment: Species: Cats require a lower dose of
lidocaine, but are more resistant to the effects of phenothiazine than dogs
Signalment: Species: Recovery in horses
Inhalants are more difficult in horses than in other species.
Signalment: Species: Anticholinergics
should be avoided in ruminants
Signalment: Species: Ventilation support is needed for
large animals (can't ventilate on their own).
Signalment:Species: Excessive airway secretions(blockages) are common in
cats & ruminants
Signalment: Species: Exotic animals
are handled differently
Signalment: Breed: Differences in Anatomy & Physiology
May affect the animal's response to anesthetic agents/procedures.
Signalment: Breed: Sighthounds
Sensitive to barbiturates
Signalment: Breed: Boxers & Giant Breeds
Sensitive to acepromazine
Signalment: Breed: Terriers
Resistant to acepromazine
Signalment: Breed: Brachiocephalic dogs
Difficult to intubate
Signalment: Breed: Draft horses
sensitive to sedatives
plays a role in drug choice in neonates, pediatrics, and geriatric patients
Signalment: Sex & Reproductive Status
Male or female? Intact or neutered? Used for breeding? Pregnant?
Signalment: Sex & Reproductive Status: Stallions
acepromazine causes priapism for days
Signalment: Sex & Reproductive Status: Pregnant Cows & Ewes
very sensitive to xylazine
Patient History: Medications
Current or past? May influence the effect of the anesthetic agents. Sympathomimetics, tricyclic antidepressants, antibiotics, monoamine oxidase (MAO) inhibitors, antihistamines
Patient History: Allergies/Drug Rx
Record in the history to prevent future administration. Cats: longer ketamine recovery;dogs: behavioral change after ace sedation.
Patient History: Preventive Care
Vx: date & type; fecal analysis/parasite control; heartworm status (dogs); FeLV/FIV in cats; Tetanus toxoid in horses.
Patient History: Past/Current Illnesses
Preexisting disease? Anorexia, V/D, coughing, sneezing, PU/PD, tenesmus, dysuria?General signs of illness? Stabilize prior to anesthesia. Change in behavior: CNS disorder, pain, systemic illness. Exercise intolerance: heart disease, anemia, musculoskeletal pain. Weakness: a nonspecific sign. Fainting/seizures: often difficult to differentiate; have different etiologies. Unexplained bleeding: bruising, blood in feces/urine; prolonged bleeding after injury. Associated w/coagulation disorders; increased risk of intra- and post-operative hemorrhage.
Patient History: Other Considerations
Written estimate; signed consent form.
Why is a signed consent form necessary?
Legally required; informs of risks; standard forms are available; should include owner's daytime phone number. Permission to use CPRC; list extralabel drugs used.
What is a physical exam and who performs it?
An evaluation to determine diagnosis and treatment planning. The veterinarian.
What is a physical assessment and who performs it?
An evaluation to provide patient care, respond to patient needs, detect changes in patient condition. The vet tech.
Why are the PE and PA necessary?
Ensures high quality patient care.
How to complete a PE/PA.
Examine the entire patient. Use a consistent technique (head to tail or organ system).
Systems most affected by anesthetic agents.
Cardiovascular, nervous, and pulmonary
Cage tags, patient ID collars, documented external characteristics in the medical record.
species, breed, size, hair coat length, color
Why is body weight so important?
Must be accurate for proper dosing
Body weight < 5kg
Body weight < 1 kg
gram scale (exotics)
body weight of a horse (kg)
[heart girth (cm)2 x length (cm)]/11880
When is an animal weighed?
immediately before an anesthetic procedure; compare with previously recorded weight.
Body condition score
assessment of pt weight w/ideal weight
On a 1-9 scale in dogs, what's the ideal weight assessment?
On a 1-9 scale in cats, what's the ideal weight assessment?
On 1-5 scale...
3 is ideal.
score of 1. Defined as extreme physical wasting
score of 5 on a 1-5 scale. Defined as extremely overweight.
Body condition influences
Fat animals are harder to anesthetize because
they're harder to awaken
skin turgor, placement of eye in orbit, mucous membrane color, refill time, moisture level (tacky, sticky, etc.), heart rate and pulse strength; correct hydration abnormalities prior to anesthesia; young & obese pts appear more hydrated, whereas old & cachetic pts appear less hydrated; panting dries out the mucous membranes.
Level of Consciousness (LOC)
To assess brain function, response to stimuli, BAR, QAR, lethargic, obtunded, stuporous, comatose
Obtunded is defined as
depressed, unable to be aroused
assesses pt's level of pain and helps select preanesthetic/anesthetic agents
is not an option. Use it!
Rectal thermometer. Elevated:inflammation; Decreased: systemic disorders.
assess from a distance: gait, temperament, activity level; will affect the choice of anesthetic agents & methods of administration
hair, skin, lymph nodes, mammary glands (visual &manual exams), body openings (odor, discharge), eyes, ears, nose, throat.oral cavity (EENT)
Pupillary Light Reflex (PLR) types
normal, direct, and consensual reflexes
Pupillary Light Reflex (PLR):normal
both are the same size
Pupillary Light Reflex (PLR): direct and consensual
both pupils react equally to light
Pupillary Light Reflex (PLR): consensual but not direct
when light is shone into the pupil, the eye does not react; however, the other eye does
Pupillary Light Reflex (PLR): direct but not consensual
when light is shown into the pupil, the eye reacts; however, the other eye does not
Cardiovascular System Exam: Heart rate
beats per minute; auscultation of left chest wall (3rd, 4th, 5th intercostal space); obese animals, panting dogs; purring cats; pediatric patients; exercise or stress of handling.
Cardiovascular System Exam: Heart rhythm: Normal Sinus Rhythm (NSR)
Dogs, cats, rodents,ferrets, rabbits, horses, ruminants
Cardiovascular System Exam: Heart rhythm: Sinus Arrhythmia (SA)
Dogs, horses, ruminants. Affected by respiration.
What is a First Degree AV Heart Block?
1 blip, then normal QRS complex. Detected only on an ECG tracing.
What is a Second Degree AV Heart Block?
More than 1 blip between QRS complex; periodic block of conduction through the AV node resulting in skipped heartbeats.
no one standardized diagnostic fits every patient
Considerations for a preanesthetic workup
geriatric, elective procedure, sick pt, based on age, history, PE; financial considerations
When is the preanesthetic workup performed?
after pt history has been taken and the PE has been completed
Preanesthetic diagnostic tests/procedures
CBC, urinalysis, blood chemistry, blood coagulation screens, ECG, radiography, other tests as deemed necessary
Physical Status Classification is based on
an evaluation of the MPD; rates pt anesthesia risk
American Society of Anesthesiologists Physical Status Classifications
Classified as P1 - P5, with P1 being the most minimal risk & P5 being the most extreme risk. P1 & P2 use standard anesthetic protocol
Which classifications use standard anesthetic protocol?
P1 - P2
Which classifications use special protocols & stabilization?
P3 - P5
What is the main consideration factor with anesthetic protocols?
familiarity with anesthetic agents
Why place an IV catheter?
fluid admin., rapid IV access in an emergency, CRI of drugs/anesthetic agents, admin. of vesicants; sequential admin, of incompatible drugs
A vesicant is
an agent that causes damage to surrounding tissues (sloughing)
IV catheter types
Through the needle; over the needle
The type of catheter most often used is the:
over the needle
Most commonly used over the needle catheter is the 16-24 gauge, 3/4 to 2" catheter for small animals
Whereas the most commonly used over the needle catheter is the 16-16 gauge, 5 1/4" catheter for large animals
Considerations for Catheter Placement and Maintenance
Length, size, location, admin. set w/injection port; free flowing fluids, minimal pt. & catheter movement, slow admin; saline flush
Steps in placing an IV catheter in a small animal patient
clip area over vein; prepare area using aseptic technique; place tape over catheter hub; hold off vein; tense skin, position catheter; advance catheter assembly thru skin; advance it further to firmly seat in the vein; advance catheter over the end of the needle; remove needle; apply pressure; attach T-port, cap, or set line to the catheter hub; secure catheter w/tape. Flush w/saline; twist the tape into a 'bowtie'; crisscross tape under & around the catheter hub; apply ointment to the plastic strip; apply plastic strip over the site of insertion; secure catheter w/tape; create tension loop w/tape.