lecture 2- patient evaluation and preparation

Dr. Wilson

who is ultimately responsible to perform the pre-anesthetic evaluation

the veterinarian incharge of the patient

what are the steps of pre-aesthetic evaluation

signalment

history

PE

pre testing

temperament/mentation and level of pain and stress

what patients should have routine ECG screening

patients with evidence of CV disease

geriatric patients

underlying disease that may lead to arrhythmias

what are some examples of underlying diseases that may lead to arrhythmias

hyperkalemia

GDV

splenomegaly

traumatic myocarditis

a young healthy patient is having an elective procedure with no abnormal history what test should be performed

PCV/TS/Glucose/BUN (“Big 4” or “QATS”)

Older patients having an elective or non-elective procedure; any history of recent illness; screening for suspected infectious disease in endemic region

CBC/Chemistry profile/UA (“minimum database”)

where is the pre-anesthetic evaluation typically performed

in the clinic but also can be done during farm/house calls

when should you perform the pre-anesthetic evaluation be beformed

usually the day before or up to a week before

why should a pre-anethetic evaluation be done on all patients

greater chance of a safe anesthetic episode

formulate an assessment of the patient’s overall function and preoperative risk

provide the client with valuable information that will help them decide based on risk

what is a category 1 on the ASA physical status scale

normal healthy patients coming in for things such as OVH, castration, ear/tail docking, declaw

what is a category 2 on the ASA physical status scale

patients with mild systemic disease

examples: Skin tumor, fracture, local infection, compensated

cardiac disease, well-controlled diabetic,

uncomplicated hernia, pregnant, obese

what is a category 3 on the ASA physical status scale

patient with severe systemic disease

Fever, dehydration, anemia, cachexia, mod. hypovolemia, uncontrolled DM, COPD, renal failure

what is a category 4 on the ASA physical status scale

patient with severe systemic disease that is a constant threat to life

Uremia, toxemia, sepsis, shock, severe dehydration, cardiac decompensation or failure, emaciation, high fever

what is a category 5 on the ASA physical status scale

moribund patients not expected to survive without operation

Extreme shock and dehydration, terminal malignancy or infection, severe trauma

what should we check when seeing what is the physical status

presence or absence of disease

severity of pain if present

level of stress and behavior

overall efficiency and function of organ systems

when should the ASA PS be assigned

after the PE is complete and the lab work or diagnostic tests have been interpreted

why is ASA physical status important

used to assess “anesthetic risk” of a case

physical status effects the PK and pD and aids in the selection of drugs and/or techniques for a patient

knowledge of what could happen helps us plan

can also be used from a legal standpoint, retrospectively

sicker the patient poorer the physical status increases what

likelihood of cardiopulmonary emergencies

T/F cats and small dogs are labeled as the same

false

what are important to consider for dosing drugs

species

size of patient

obesity

age

neonate or pediatric age will do what for dosing

decrease dose

juvenile to early adulthood will do what for dosing drugs

increase dose

geriatric patient will do what for dosing drugs

decrease dose

what should we perform as patient preparation

hygiene and patient comfort

correct dehydration and electrolyte imbalance

preoperative antibiotics

specific prep for the patient

how long should a dog or cat fast

6-12

how long should a small ruminant, calves and camelids fast

12-18 hours

how long should equine fast before surgery

4-12 hours

how long should cattle fast before surgery

18-24 hours

how long should swine fast before surgery

12-24 hours

how long should birds fast before surgery

4-6 hours

what animals do not have to fast before surgery

rodents, rabbits, birds <200g, neonates

why is a patient fasted prior to general anesthesia

Decrease food and fluid in stomach

Decrease risk of aspiration

Distended stomach or rumen impairs ventilation and could lead to hypoxemia and hypercapnia

In horses, a full stomach could rupture at induction

why is it not necessary for neonates, small birds and some mammals

prone to hypoglycemia within a few hours of starvation

increased metabolic rate in birds and small mammals

what are the 4 H’s in anesthetic concerns

1. hypotension

2. hypoventilation

3. hypothermia

   1. hypoxemia