anaesthesia- preoperative evaluation

anesthesia is..

the controlled intoxication of the system

in anesthesiology, we need to know the ______ of our patient in order to know if our drugs are safe

physiology

what are the 3 goals of anesthesia?

1. prevent response to pain

2. provide restraint and immobility of the animal + relaxation of the skeletal muscles

3. loss of consciousness (hypnosis)

how does anesthesia affect the animal's metabolism?

depresses the metabolism

how does anesthesia affect the animal's cardiovascular and respiratory system?

depresses them

what does anesthesia do to the animal's immune response?

depresses it

what is important to know about Dobermans before surgery?

73% of them have low Von Willebrand factor, so they bleed more easily

what is important to know about brachycephalic breeds before surgery?

they have a hypoplastic trachea, elongated soft palate, everted laryngeal saccules, and stenotic nares- so have a difficult time with respiration

what is important to know about collies before surgery?

they have a mutation of the MDR1 gene, which makes it difficult for them to metabolize drugs

what is important to know about king charles spaniels and main coons before surgery?

they commonly have cardiac problems

what are the 5 objectives of the preoperative evaluation?

1. evaluate the health condition of the patient

2. classify the type of intervention

3. determine the mortality/prognosis

4. anesthetic protocol

5. legal informed consent

what are the 3 steps of the preoperative evaluation?

1. anamnesis

2. physical exam

3. additional tests

what information is important to get in the anamnesis?

breed, age, allergies, feeding, contact with other animals, vaccinations, deworming, reproductive status, previous illness, medication, previous anesthesia, etc

what type of questions are most appropriate to ask the owner during the anamnesis?

OPEN questions (not yes/no)

describe the physical exam that we must complete during the preoperative evaluation.

it needs to be complete (nose to tail)

we need to assess the attitude, BCS, lymph nodes, mucosa, eyes, skin, ears, perform an abdominal palpation and auscultation and get the animal's vital signs

what difference does a high BCS make for operations?

some drugs are lipophilic, so in overweight animals, it will bind to their fat and not work.

what additional test must we ALWAYS perform before an operation?

blood test, biochemistry test, thoracic Xray

what types of additional tests can be ran on the animal for the preoperative evaluation?

blood tests

urinary test

ECG

Xray

ultrasound

if we perform a preoperative blood test and discover the patient has anemia, what is important to adjust for their anesthesia?

provide a higher saturation of O2

why is it important to check the renal and hepatic enzymes of a patient before operation?

because the liver and kidney are necessary for drug elimination

why is a danger to anesthetize a patient with low proteins?

because the drugs need to bind to proteins, and if they can't, they can overdose the patient

what are the important values to check when we perform a preoperative blood analysis on a patient?

RBC- if they have anemia, we provide them with more O2

WBC- because anesthesia suppresses the immune system

proteins- needed for drug binding

glucose- tells us the metabolic state

renal and liver enzymes- needed for drug elimination

we should always perform a _______ xray before operation

thoracic

when do we do the preoperative evalutation?

1 week before the operation

if it is done too early, the patient's condition can change in the time between, and if it is done late, there might be a problem we need to address before surgery can happen

what is the ASA classification?

"American Society of Anesthetics" used to assess the status of the patient so that we can choose the most suitable protocol and prepare the monitor for the specific patient. it is a range from I-V, V being the worst condition.

what does ASA I mean?

the patient is healthy, they are doing a selective surgery (ex: neuter/spay)

what is the least concerning level of ASA?

I- this means that the patient is healthy, they are doing a selective surgery

what is the state of a patient that we classify as ASA II?

they have a local or mild systemic disease, and can react normally to the drugs. they have no functional limitation

describe a patient that we classify as ASA III.

they have a moderate systemic disease, with functional limitation

if we have a patient going into surgery with a severe, life threatening systemic disease, we classify them as ASA ______

IV

what is ASA IV?

severe systemic disease that is a constant threat to life

a patient that is classified as ASA V is in this state:

unlikely to survive, even with the surgery

what does it mean if an "E" is added to the end of the ASA score?

it means that the patient is an emergency patient. an E can be added to any ASA score, except I

how do we give an ASA rating to a very juvenile or senior patient?

we +1 to their score

at what age is the animal too old for anesthesia?

never, any age can undergo anesthesia