Anesthesia Mid Term 2025

What is the difference between an agonist and an antagonist?

An agonist binds to a receptor and activates it, producing a response, while an antagonist binds to a receptor but blocks or dampens the response.

What is the difference between analgesia and anesthesia?

Analgesia is pain relief without loss of consciousness, while anesthesia induces a loss of sensation and possibly consciousness.

What happens when incompatible drugs are mixed in one syringe?

They may precipitate, inactivate each other or cause harmful reactions.

Why do we administer premedication?

To provide sedation, reduce stress, decrease anesthetic requirements, and manage pain.

Rank IM, IV, and SQ administration in terms of speed and duration of action.

• IV = fastest onset, shortest duration

• IM = faster onset, shorter duration

• SQ = slowest onset, longest duration

What are the effects and side effects of Acepromazine?

Effects: Sedation, pre-anesthetic tranquilizer (no pain relief), anti-emetic, prevents histamine release, smooths induction/recovery.

Side effects: dose-dependent hypotension, peripheral vasodilation, lowers seizure threshold. (No reversal agent, metabolized by liver, slowly crosses placenta)

What are the effects and side effects of benzodiazepines?

They include: Diazepam, Midazolam, Zolazepam

Effects: Calming & anti-anxiety (only in old/ill patients), anticonvulsant, muscle relaxation, appetite stimulation (cats/ruminants), potentiates anesthetics, minimal cardiovascular/respiratory effects, no pain control.

Side Effects: Poor sedative in healthy animals, no analgesia, diazepam not water-soluble (can’t mix with certain drugs), must be stored properly (light-sensitive, no plastic).

What are the effects and side effects of alpha-2 agonists?

They include: Xylazine, Detomidine, Romifidine, Dexmedetomidine

Effects: Dose-dependent sedation, mild analgesia, muscle relaxation; used as a pre-med for anesthesia or minor procedures; reversible with alpha-2 antagonists (Atipamezole, Yohimbine, Tolazoline).

Side Effects: Bradycardia, peripheral vasoconstriction (pale MM), hypertension, cardiac arrhythmias (AV block); later phase can cause hypotension and decreased cardiac output; sedation is dose-dependent, but patients can still react/bite.

What are the effects and side effects of opioids?

They include: Morphine, Hydromorphone, Fentanyl, Buprenorphine, Butorphanol

Effects: Sedation in dogs, CNS stimulation in cats, horses, ruminants (use lower dose), analgesia (best with full mu agonists for severe pain), used as a premed for painful surgery.

Side Effects: Bradycardia, respiratory depression, dysphoria, excitement, anxiety, GI slowdown, dose-dependent effects; reversed with Naloxone.

What kind of drugs are buprenorphine and butorphanol?

Buprenorphine: Partial mu agonist, provides moderate pain relief with a longer duration, but less potent than full mu agonists. Schedule III.

Butorphanol: Kappa agonist, mu antagonist, provides mild analgesia, good sedation, and cough suppression. Schedule IV.

What is neuroleptanalgesia?

A state of profound sedation and analgesia induced by a combination of an opioid and a tranquilizer. (e.g., Acepromazine (tranquilizer) + Butorphanol (opioid))

What are the effects and contradictions of Propofol?

Effects: Dose-dependent CNS depression (sedation to anesthesia), no analgesia, cardiac depressant (transient hypotension), respiratory depressant (possible apnea—give slowly).

Contraindications: Hypoproteinemic animals (highly protein-bound), may cause excitement if given too slowly.

How does ketamine differ from other anesthetics?

It maintains muscle tone, causes eyes to remain open, and increases heart rate.

What is the Ketamine-Diazepam combination used for?

Induction; provides muscle relaxation and smooth recovery

What is the difference between sedation and tranquilization?

Sedation: reduces mental activity and causes sleepiness (Decreased responsiveness to external stimuli)

Tranquilization: reduces anxiety without reduction of mental activity (Calming effect w/o sleepiness)

Why is balanced anesthesia important?

It minimizes side effects and enhances patient stability by using multiple drug classes.

What is the difference between E and H tanks?

E tank: Small and portable

H tank: Large and stationary

Where do you measure the flowmeter reading if there is a ball?

At the center of the ball

What are the functions of the vaporizer and pop-off valve?

Vaporizer: Converts liquid anesthetic into gas.

Pop-off valve: Prevents excessive pressure in the system.

What are soda lime granules made of, and what do they do?

Made of calcium hydroxide; they absorb CO2.

What is the difference between passive and active scavenging?

Passive: Uses gravity/ventilation to remove waste gases.

Active: Connected to a building source. Uses a vacuum system.

What are WAGs?

Waste Anesthetic Gases that must be scavenged to prevent exposure

What is atelectasis?

Collapse of lung alveoli, leading to impaired gas exchange

What are the goals of general anesthesia?

That the patient doesn’t move, isn’t aware, doesn’t feel pain, has no memory of the procedure, and survives.

What are the stages of anesthesia?

Stage 1: Period of voluntary movement

Stage 2: Period of involuntary movement

Stage 3: Period of surgical anesthesia (Plane 2 = ideal for surgery, “Goldilocks plane”)

Stage 4: Overdose

What are some common reflexes monitored under anesthesia?

• Auricular: ear flick

• Pedal: withdrawal

• Palpebral: blink

• Corneal: used for euthanasia

• Laryngeal: reflex should be gone for ET tube.

• Anal tone

• Jaw tone

How do eye position and pupil size change during anesthesia?

Initially central, then ventromedial in surgical anesthesia, the central again if too deep.

How do you monitor circulation, ventilation, and oxygenation?

Circulation: HR and rhythm, pulse strength, CRT, MM color, and BP

Ventilation: RR and depth, breath sounds, end-expired CO2 levels, arterial carbon dioxide, and blood pH

Oxygenation: MM color, CRT, hemoglobin saturation (Pulse Ox) , inspired oxygen and arterial blood oxygen.

What is the difference between hypoventilation and hyperventilation?

Hypoventilation: Slow, shallow breathing, CO2 retention

Hyperventilation: Fast breathing, CO2 depletion

What is the formula for tidal volume?

Tidal Volume (TV): 10-15 mL/kg x Body Weight (BW in kg)

What is the normal ETCO2 for a patient under general anesthesia?

35 - 55 mmHg

What is hypercarbia and hypocarbia?

Hypercarbia: High CO2, caused by hypoventilation

Hypocarbia: Low CO2, caused by hyperventilation

What are the lower limits for HR, RR, and BP under general anesthesia?

HR: Dog 60BPM, Cat 100BPM, Horse 25BMP

RR: Average 8 breaths per min

BP: Small animals MAP > 60mmHg, Horse MAP >70mmHg

What does pulse oximetry measure?

Oxygen saturation of hemoglobin in the blood

What belongs in each SOAP section?

(S)ubjective: Patient History, Owner Concerns

(O)bjective: What you can see and measure

(A)ssessment: Diagnosis

(P)lan: Treatment

What is the role of the LVT before surgery?

Prepare equipment, calculate drug doses, premed + IV Cath, intubate, and monitor patient stability

What should be on a consent form?

• Medications given/not given

• Last meal (fasted?)

• Procedure details & risks

• CPR code (permission to preform)

• Written Estimate

• Owner’s signature, contact info, and availability

Why is fasting important before anesthesia?

By doing so can prevent: Esophageal reflux, vomiting, regurgitation, and pulmonary aspiration pneumonia

What is a Minimum Patient Database?

Baseline patient health info.

Includes: patient history, physical exam, and preanesthetic diagnostic workup (varies by age/signalment). May include PCV, TP, glucose, CBC, biochemistry, electrolytes, fecal, HWT, radiographs, ECG, +/- ultrasound.

How do you assess hydration?

Skin turgor, placement of eye in orbit, MM color, CRT, MM moisture level, HR and pulse strength.

What are the different fluid compartments in the body?

Intracellular (ICF) - fluid within the cells themselves

Extracellular (ECF) - is made up of:

• Vascular - fluid that is found in the blood vessels

• Interstitial - fluid between the cells

What is the difference between crystalloids and colloid fluids?

Crystalloids: Small molecules, that may contain dextrose/buffers and are used for fluid replacement (e.g., LRS, Normosol-R, saline, dextrose solutions). Can shift between compartments.

Colloids: Large molecules, replace albumin, stay in intravascular space, used for blood volume & pressure support (e.g., Hetastarch, plasma, whole blood).

When do we use dextrose-containing fluids?

Used to support blood sugar levels. (For hypoglycemia or neonates)

What are signs of overhydration?

• Ocular and nasal discharge

• Chemosis (swelling of the conjunctiva)

• Subcutaneous edema (swollen limbs)

• Increased lung sounds, pulmonary edema.

• Increased respiratory rate and dyspnea

• Coughing and restlessness if the patient is awake

• Hemodilution (a decrease in blood cell concentration due to an increase in plasma volume)

What are the ASA anesthetic risk categories?

ASA 1: Healthy - minimal risk

ASA 2: Mild systemic disease - slight risk (neonate, geriatric, mild dehydration)

ASA 3: Obvious systemic disease - moderate risk (anemia, Low grade cardiac disease, liver disease)

ASA 4: Severe systemic disease - high risk (shock, emaciation, high fever, uncompensated heart disease)

ASA 5: A state of near death *a patient not expected to survive w/o sx - extreme risk (severe trauma, profound shock, advanced heart disease)

What is the role of the LVT in analgesia?

• Monitor and assess pain — report to DVM

• administer and log analgesics

• observe during recovery

• educate owners on home pain management.

What is the difference between somatic and visceral pain?

Somatic pain: From bones, joints, muscles, or skin; localized, sharp, aching, or throbbing.

Visceral pain: From organ stretching, distention, or inflammation; deep, cramping, aching, or gnawing, poorly localized.

What are nociception and pain threshold?

Nociception: Pain receptors that transduce noxious stimuli into electrical impulses.

Pain threshold: Level at which pain is perceived.

What is preemptive analgesia?

Administering analgesics before painful stimulation to prevent sensitization and improve postoperative pain management.

What is multimodal analgesia?

The use of multiple drugs with different actions to optimize pain control and reduce side effects.