Anesthesia Induction and Intubation - Veterinary Nursing Level 2

Vocabulary practice flashcards covering pre-anesthetic medications, injectable and inhalant pharmacology, ventilation fundamentals, and endotracheal intubation techniques and complications.

Alpha-2 Agonists (Mechanism of Action)

Sedatives that bind to and stimulate alpha-2 receptors on the synaptic knob of norepinephrine-secreting neurons, decreasing norepinephrine release in both the CNS and PNS to produce sedation and muscle relaxation.

Xylazine (Cardiovascular Effects)

An alpha-2 agonist that sensitizes the myocardium to catecholamines (increasing dysrhythmia risk), causes marked peripheral vasoconstriction, produces sinoatrial and AV heart blocks, bradycardia, and leads to hypotension.

Yohimbine

A pharmacological antagonist used as a reversal agent for the alpha-2 agonist xylazine.

Atipamezole

The preferred reversal agent (alpha-2 antagonist) used to reverse the effects of dexmedetomidine.

Neuroleptanalgesic

A drug combination consisting of a neuroleptic (tranquilizer) and an analgesic (narcotic/opioid) that acts synergistically to enhance CNS depression (e.g., diazepam and oxymorphone).

Drug Redistribution (Injectable Anesthetics)

The process by which lipophilic drugs rapidly distribute to vessel-rich, well-perfused organs (brain, liver, kidneys) to induce anesthesia, and subsequently diffuse into poorly perfused tissues (adipose, inactive muscle), causing blood and brain concentrations to fall and the patient to regain consciousness.

Protein-Bound Drug Fraction

The proportion of an anesthetic molecule bound to plasma proteins (albumin and globulin) that cannot cross capillary membranes into tissues; only the unbound 'free' drug is pharmacologically active.

Dissociative Anesthetics

A class of anesthetic agents derived from phencyclidine (such as ketamine and tiletamine) that induce a cataleptic state characterized by CNS excitement rather than depression, producing somatic analgesia, immobility, and amnesia.

Apneustic Ventilation

An abnormal breathing pattern typically produced by ketamine, characterized by prolonged inspiratory pauses followed by short, incomplete expirations.

Telazol

A proprietary injectable anesthetic combination comprising tiletamine hydrochloride (a dissociative) and zolazepam hydrochloride (a benzodiazepine tranquilizer).

Propofol-28

A proprietary formulation of propofol containing benzyl alcohol as a preservative that provides a 28-day shelf life after broaching, but is contraindicated in cats due to benzyl alcohol toxicity.

Heinz Bodies

Oxidative inclusions of denatured hemoglobin formed inside feline erythrocytes following repeated or prolonged administration of propofol.

Alfaxalone

A neuroactive steroid Class IV controlled injectable anesthetic that acts via GABA receptors in the CNS, causing dose-dependent respiratory depression and requiring unused contents to be discarded after 6 hours.

Etomidate

A non-water-soluble sedative-hypnotic formulated in propylene glycol that provides rapid induction and recovery with minimal cardiopulmonary depression, making it ideal for high-risk cardiac or cesarean section patients.

Double Drip

An intravenous anesthetic protocol combining guaifenesin (GG) and ketamine, commonly used for the induction and maintenance of short procedures in ruminants.

Triple Drip

An intravenous total intravenous anesthesia (TIVA) protocol combining guaifenesin (GG), xylazine, and ketamine, administered as a constant rate infusion (CRI) for procedures lasting $1\,\text{hour}$ or less in horses.

Minimum Alveolar Concentration (MAC)

The lowest alveolar concentration of an inhalant anesthetic vapor that prevents purposeful motor response to a painful stimulus in $50\%$ of patients; lower values reflect higher potency.

Blood:Gas Solubility (Inhalants)

A measure of how readily an inhalant anesthetic dissolves in blood and tissues; drugs with low solubility diffuse rapidly into the brain, resulting in faster induction and recovery.

Methoxyflurane

A methyl-ethyl ether inhalant agent characterized as the most potent inhalant ($\text{MAC} = 0.23\%$), having high lipid solubility (prolonged induction and recovery), and producing potential hepatotoxicity and nephrotoxicity through its $50\%$ hepatic metabolism.

Halothane

A halogenated hydrocarbon inhalant anesthetic ($\text{MAC} = 0.9\%$) that is $20\text{--}25\%$ metabolized by the liver, sensitizes cardiac myocardium to catecholamines, and can induce severe arrhythmias, hypotension, and hypothermia.

Isoflurane

A halogenated ether inhalant anesthetic with an $\text{MAC}$ of $1.3\%$ and low blood solubility, characterized by maintaining a stable cardiac rhythm and undergoing less than $0.2\%$ metabolism.

Sevoflurane

A halogenated ether inhalant with an $\text{MAC}$ of $2.4\%$ that is $3\%$ metabolized, has a non-pungent odor, and exhibits the lowest solubility of volatile agents for rapid induction and recovery.

Diffusion Hypoxia

A complication occurring upon cessation of nitrous oxide when the gas rapidly diffuses from the blood into the pulmonary alveoli, displacing alveolar oxygen and requiring the patient to be placed on $100\%\,\text{O}_2$ for $5\text{--}10\,\text{minutes}$.

Positive Pressure Ventilation (PPV)

The active mechanical or manual delivery of respiratory gases into a patient's lungs by closing the pop-off valve and compressing the rebreathing bag, indicated when $\text{PaCO}_2 > 60\,\text{mmHg}$ or in cases of apnea.

Positive End-Expiratory Pressure (PEEP)

The maintenance of positive airway pressure (typically $2\,\text{cm H}_2\text{O}$) above atmospheric pressure at the end of expiration to prevent small airway and alveolar collapse in conditions such as pulmonary edema.

Murphy Eye

The oval secondary side opening located near the patient end of an endotracheal tube that provides an alternate pathway for gas exchange if the main bevel becomes obstructed.

Endotracheal Tube Anatomy

The structural design of an ET tube comprising the machine-end connector, graduation markings, radiopaque line, Murphy eye, bevel, inflatable cuff, inflation tube, pilot balloon, and one-way spring-loaded inflation valve.

Endobronchial Intubation

An intubation error occurring when an excessively long tube passes the carina into a mainstem bronchus, resulting in one-lung ventilation, hypoxemia, dyspnea, and an unexpectedly light plane of anesthesia.

Endotracheal Tube Lumen Compression

Airway obstruction caused by over-inflation of the endotracheal cuff collapsing or narrowing the internal lumen of the tube, a risk heightened when using soft silicone rubber tubes.

Laryngospasm

A reflex spasm and closure of the vocal cords and arytenoid cartilages commonly triggered during endotracheal intubation in cats, prevented by applying topical lidocaine to the glottis.