Intro/Considerations Prior to General Anesthesia

Question 1

What is analgesia?

Answer 1

Diminished pain perception and autonomic responses to nocicipetion

Question 2

What is tranquilization?

Answer 2

A state of tranquility and calmness in which the animal is awake, relaxed, and unconcerned about its surroundings. The animal is easily arousable and will respond to painful stimuli

Question 3

What is sedation?

Answer 3

Depresses CNS more than tranquilization so that the animal is awake and sleepy, but still able to be aroused by stimulation.
Minor manipulations can be performed, and aggressive animals will be easier to handle after sedation

Question 4

What is local analgesia/anesthesia?

Answer 4

Administration of a local agent to desensitize a part of the body.
An animal is not unconscious if local anesthetic drugs are the only form of anesthesia provided, but chemical or manual restraint may be necessary to perform the anesthesia

Question 5

What is regional analgesia/anesthesia?

Answer 5

A local anesthetic in which specific nerve blocks are performed to desensitize a certain part of the body

Question 6

What is general anesthesia?

Answer 6

Drug-induced, controlled, reversible loss of consciousness and sensation

Question 7

What is surgical anesthesia?

Answer 7

Loss of consciousness and sensation accompanied by sufficient muscle relaxation and analgesia to allows for surgery with or without pain or movement by the animal

Question 8

What is balanced anesthesia?

Answer 8

Anesthesia that uses a combination of drugs, each in an amount sufficient to produce its major or desired effect to the optimum degree and to keep undesirable effects to a minimum

Question 9

What is dissociative anemia?

Answer 9

A type of general anesthesia where the animal is “dissociated” from its surroundings and unaware of external stimuli

Question 10

What are the 5 necessary components of general anesthesia?

Answer 10

Unconsciousness
Amnesia
Analgesia/anti-nociception
Immobility
Attenuation of autonomic response to noxious stimuli

Question 11

An animal in stage 2 would show what kind of signs? Is this animal aware of its environment?

Answer 11

Stage 2 is characterized by delirium or involuntary excitement
No, stage 2 lasts from loss of consciousness to onset or regular breathing

Question 12

Up to this point, your sophomore surgery dog has been quite stable at 1.25% isoflurane. However, when the ovarian pedicle is stretched, your dog’s heart rate and respiratory rate increase. Is this dog: 1) awake and feeling pain? 2) Purposefully responding to inadequate anesthesia? 3) Showing signs of autonomic stimulation?

Answer 12

1) No. Animals cannot feel pain when they are unconscious and the animal is still unconscious
2) No
3) Yes. Anesthetized animals can autonomically and reflexively respond to noxious stimulation

Question 13

Medicine wishes to “sedate” a dog for percutaneous liver biopsy. Will sedation be sufficient to perform this procedure? Why or why not?

Answer 13

No. Sedation can be used with minor manipulations, but they can still be aroused by stimulation

Question 14

When queried further, Medicine would prefer the dog for the percutaneous liver biopsy to be unconscious, relaxed, analgesic, and nonresponsive to surgical stimulation. What term would best describe their request?

Answer 14

Surgical anesthesia

Question 15

What is the minimum amount of laboratory data that should be obtained before anesthetizing a young, healthy animal? Why is this information important?

Answer 15

Packed cell volume and total protein
TP measures the oncotic pressure and the capacity for fluid administrations.
PCV measures the oxygen-carrying capacity

Question 16

Give an example of a type of patient that would be classified with each of the ASA physical status classes I through V.

Answer 16

Class 1: normal healthy patient; elective procedure (OHE, castration, TPO, etc.)
Class 2: mild systemic disease, well compensated; uncomplicated orthopedic injury, localized controlled infection, mild compensated disease
Class 3: Moderate systemic disease that is ongoing but compensated, some functional limitations exist which increase the risk of anesthesia; traumatize animal with significant fractures and hemorrhage, congestive heart failure with clinical signs of reduced cardiac reserve, moderate hypovolemia, azotemia, diabetes mellitus, severe obesity
Class 4: Severe systemic disease which is a constant threat to life, uncompensated disease, high anesthetic risk because vital body systems are involved; acute gastric dilatation volvulus, life-threatening hemorrhage, severe toxemia or icterus, respiratory distress; severe colic, uncompensated heart disease, life-threatening anemia
Class 5: Moribund patient not expected to live more than 24 hours with or without surgery

Question 17

What types of abnormalities should be corrected prior to the administration of anesthetic drugs? Explain why.

Answer 17

Abnormalities of the cardiovascular, respiratory, central nervous, hepatic, and renal systems are particularly important. These systems are all heavily involved with a patient that is under anesthesia, so a problem in one of these must be corrected to help keep the patient stable while unconscious.

Question 18

What are the minimum physical exam findings that the anesthetist should be familiar with before administering anesthetic drugs?

Answer 18

Auscultate the heat and lungs
Note any abnormal cardiac rhythms or murmurs
Palpate a peripheral pulse and record heart rate
Note an abnormal lung sounds and record respiratory rate
Note the color of the mucous membranes and the CRT
Evaluate the hydration status
Note the patient’s mentation and behavior

Question 19

What information is necessary to formulate an anesthetic care plan?

Answer 19

Patient evaluation, which assess the patient’s demeanor and baseline health status
Patient preparation, which includes the nature of the procedure to be performed, a means to monitor the patient, a knowledge of potential complications associated with both the procedure and the anesthetic procedure, and a means to treat any complications which arise

Question 20

What does the designation “E” denote in a patient’s physical status?

Answer 20

Emergency surgery or anesthetic which must be done immediately regardless of physical status
Added to a class (2E, 4E)

Question 21

True or false: During anesthesia, consciousness may not be associated with connectedness, responsiveness, or recall

Answer 21

True
Consciousness is common in anesthesia as evidenced by dreaming
Consciousness likely depends on the integrity of the corticothalamic networks
Spontaneous responsiveness may depend on subcortical and spinal cord networks
Connectedness may depend on continue information integration in corticothalamic circuits and unperturbed norephrinergic signaling

Question 22

A dog which received a severe brain injury following a big dog-little-dog incident is recovering in ICU. The dog is in lateral recumbency, vocalizing, breathing spontaneously, and exhibits various reflexes, including corneal and palpebral, but does not respond purposefully to touch or verbal commands. Are these signs of Connectedness? Responsiveness? Conscious perception?

Answer 22

These are signs of responsiveness