Week 1 Lesson 3 pt 1 Induction Maintenance

What is the definition of anesthesia induction?

The transition of a patient from a conscious state to an unconscious state.

Which property of an inhalant anesthetic primarily determines the speed of induction and recovery?

The blood-gas solubility coefficient.

What blood-gas solubility coefficient value is desired for rapid induction and recovery?

A low blood-gas solubility coefficient.

Name five commonly used injectable anesthetic agents listed in the learning outcomes.

Thiopental, propofol, etomidate, alfaxalone, and ketamine.

Name six inhalant anesthetics evaluated in the learning outcomes.

Isoflurane, sevoflurane, halothane, desflurane, xenon, and nitrous oxide.

What is the first item on the checklist when preparing a patient for induction?

Having an intravenous (IV) catheter in place.

How long should a patient be preoxygenated prior to induction according to the clinical scenario?

For 5 minutes using a face mask.

What is the primary purpose of preoxygenating a patient before induction?

To increase the time before hypoxemia develops during the apneic period following induction.

Name three physiological parameters that must be checked before induction.

Heart rate (HR), respiratory rate (RR), and mucous membranes (MM).

What safety action should be performed immediately before inducing the patient?

Perform the safety checklist.

What must you assign to another person during the induction process?

To monitor the patient while you induce them.

What drug-related checks should be made when preparing for induction?

Check drug labels and dosages.

What equipment-related checks should be made when preparing for induction?

Check the anesthesia machine and the breathing system.

To which drug class does Thiopental belong?

Barbiturates.

What are the onset and duration of Thiopental when administered intravenously?

Onset of 20 to 30 seconds and duration of 10 to 15 minutes.

Which receptor does Thiopental act on as a strong agonist?

GABAA receptor.

What breed of dog is Thiopental specifically contraindicated in?

Greyhounds.

Why is Thiopental contraindicated in Greyhounds?

It causes pronounced cardiac depression and long recoveries.

Is Thiopental suitable for administration as a Constant Rate Infusion (CRI)?

No, it is not suitable for CRI.

Does Thiopental provide any analgesic properties?

No, it provides no analgesia.

What is the effect of Thiopental on intracranial pressure (ICP)?

It decreases intracranial pressure.

How does Thiopental affect the brain's oxygen requirements?

It decreases the oxygen requirements of the brain.

Why is Thiopental a poor choice for hemodynamically compromised patients?

It causes dose- and rate-dependent cardiovascular and respiratory depression.

What specific cardiac arrhythmias can be caused by Thiopental?

Premature ventricular contractions (PVCs) and bigeminy.

What is the onset and duration of Propofol when administered intravenously?

Onset of 30 to 60 seconds and duration of 10 to 15 minutes.

Which receptors does Propofol act on and with what strength?

It is a strong GABAA enhancer (+++) and a weak NMDA antagonist (+).

Does Propofol provide any analgesia?

No, it provides no analgesia.

What are the main clinical indications for Propofol?

Induction, maintenance (TIVA), anticonvulsant (CRI), C-sections, and head trauma.

Why is Propofol acceptable for use in C-section procedures?

It is acceptable for use in C-sections.

What is the shelf life of standard preservative-free lipid emulsion Propofol?

6 hours.

What preservative is added to multidose Propofol formulations to extend its shelf life?

Benzyl alcohol.

What is the shelf life of multidose Propofol containing benzyl alcohol?

28 days.

In which species is multidose Propofol containing benzyl alcohol approved?

Dogs only.

Why is multidose Propofol not suitable for Constant Rate Infusion (CRI)?

Due to the presence of benzyl alcohol preservative.

Why can Propofol not be administered as a Constant Rate Infusion (CRI) in cats?

Cats have a reduced glucuronidation capacity.

What hematological risk is present in cats given repeated doses of Propofol?

Feline hemoglobin is prone to oxidative injury, leading to decreased PCV and Heinz body anemia.

What clinical signs can appear in cats from repeated Propofol doses?

Prolonged recoveries, anorexia, depression, diarrhea, and facial edema.

What pre-existing gastrointestinal condition is a caution for Propofol use due to its lipid emulsion?

Pancreatitis.

What neurological motor signs can sometimes be seen with Propofol administration?

Myoclonus, nystagmus, and opisthotonus.

What is Ciprofol?

A short-acting intravenous induction agent based on the structural modification of propofol.

What are the clinical benefits of Ciprofol based on its structural modification?

High efficacy, good selectivity, and fewer adverse reactions.

Is Ciprofol currently used in veterinary medicine?

No, it is not yet used in veterinary medicine.

What is the lipid-emulsion formulation of Etomidate called?

Etomidate-Lipuro.

What is the shelf life of Etomidate-Lipuro?

24 hours.

What are the onset and duration of Etomidate when administered intravenously?

Onset of 60 seconds and duration of 10 to 20 minutes.

Which receptor is Etomidate a strong agonist for?

GABAA receptor (+++).

Does Etomidate provide any analgesia?

No, it provides no analgesia.

What are the primary clinical indications for Etomidate?

Induction in combination with a benzodiazepine or fentanyl, and patients with low cardiac reserve or hypovolemia.

What endocrine side effect is caused by a single dose of Etomidate?

Inhibition of adrenal steroid synthesis (specifically aldosterone, cortisol, and corticosterone) for 2 to 6 hours.

What condition is an absolute caution for Etomidate use unless cortisol supplementation is provided?

Known adrenal insufficiency.

What is a common neuromuscular side effect seen during Etomidate induction?

A high incidence of myoclonus.

Can Etomidate be administered as a Constant Rate Infusion (CRI)?

No, it is IV only and not suitable for CRI.

What is the shelf life formulation characteristic of Alfaxalone?

It is a long shelf-life formulation.

Through what routes can Alfaxalone be administered?

IV, IM, and CRI.

What are the onset and duration of Alfaxalone when administered intravenously?

Onset of 60 seconds and duration of 10 minutes.

Which receptor does Alfaxalone act on?

GABAA receptor (+++).

Does Alfaxalone provide any analgesic effect?

No, it provides no analgesia.

What are the primary clinical indications for Alfaxalone?

Induction, maintenance, and C-section.

How does the respiratory depression caused by Alfaxalone compare to Propofol?

Alfaxalone causes less respiratory depression/apnea than propofol.

What adverse recovery signs can be seen in cats after Alfaxalone administration without a sedative?

Myoclonus and opisthotonus.

What is the federal scheduling class of Ketamine according to the FDA?

FDA Schedule III.

What type of anesthesia is Ketamine classified as?

Dissociative anesthesia.

What is the neurological mechanism of Ketamine described as?

Functional disorganization of the CNS, specifically desocialization between the limbic and thalamocortical systems.

What are the onset times of Ketamine via intramuscular (IM) and intravenous (IV) routes?

Onset IM is 5 to 10 minutes

What is the typical duration of action of Ketamine?

30 to 45 minutes.

What receptor is Ketamine a strong antagonist for?

NMDA receptor (+++).

Which other receptors does Ketamine act on as a weak or moderate agonist?

Mu (μ), kappa (κ), delta (δ) opioid receptors (+), GABA receptors (+), and alpha1, beta2 receptors (++).

Does Ketamine provide analgesia?

Yes, it provides analgesia.

What are the clinical indications for Ketamine?

Induction (with propofol or BZD), maintenance (TIVA), analgesia (CRI), and chemical restraint.

How does a Constant Rate Infusion (CRI) of Ketamine benefit pain management?

It provides analgesia that helps prevent central sensitization and hyperalgesia.

What are the cardiovascular effects of Ketamine?

It increases heart rate, blood pressure, inotropism, cardiac output, intracranial pressure, and intraocular pressure.

Under what condition can Ketamine cause decreased inotropism?

In patients who are adrenally depleted.

What respiratory pattern is classically associated with Ketamine anesthesia?

An apneic respiratory pattern (apneustic pattern).

What beneficial effect does Ketamine have on the airways?

Bronchodilation.

What muscle tone characteristic is seen with Ketamine use?

Muscle rigidity.

What happens to protective reflexes under Ketamine anesthesia?

Reflexes are maintained, but without their protective function.

In what cardiac condition is Ketamine contraindicated or used with extreme caution?

Hypertrophic cardiomyopathy.

Why is Ketamine cautioned in head trauma patients?

It increases intracranial pressure (ICP).

Why is Ketamine cautioned in C-sections?

It is associated with increased maternal and fetal mortality and decreased neonatal vigor compared to other options.

What adjustment must be made for Ketamine administration in cats with kidney disease?

The dose must be reduced.

What is Tiletamine-zolazepam commercially known as?

Tilazol.

What is the drug class composition of Tilazol?

Tiletamine (an NMDA antagonist) and Zolazepam (a GABAA agonist).

What are the onset times of Tiletamine-zolazepam via IM and IV routes?

Onset IM is 5 to 10 minutes

What is the duration of action of Tiletamine-zolazepam?

30 to 60 minutes.

What are the key indications for Tiletamine-zolazepam?

Induction (with propofol or BZD), chemical restraint, and heavy sedation for diagnostic procedures.

Why should you avoid redosing Tiletamine-zolazepam?

It causes prolonged and rough recoveries.

What adverse recovery signs can be seen in dogs after Tiletamine-zolazepam administration?

Muscle rigidity, excitation, and seizure-like activity during recovery.

How does the respiratory depression of Tiletamine-zolazepam compare to Ketamine?

It causes more respiratory depression compared to ketamine.

In what patients is Tiletamine-zolazepam cautioned?

Patients with head trauma, hypertrophic cardiomyopathy, and critically ill patients.

What is Total Intravenous Anesthesia (TIVA)?

Induction and maintenance of anesthesia using only injectable anesthetic agents and an analgesic agent.

How can maintenance of anesthesia be achieved during TIVA?

By intermittent boluses or Constant Rate Infusion (CRI).

Give an example of an induction and maintenance protocol for TIVA.

Induction with propofol and ketamine, and maintenance with propofol, ketamine, and fentanyl.

What does TCI stand for in intravenous anesthesia?

Target-Controlled Infusion.

What is Target-Controlled Infusion (TCI)?

A computer-driven pump using pharmacokinetic models to automatically maintain a specific drug concentration in a patient's plasma.

What are two drugs commonly administered via TCI?

Propofol and remifentanil.

What are the key indications for using TIVA?

Airway procedures, bronchoscopy, and field procedures (such as in horses and ruminants).

What is the primary reason for administering a partial propofol dose before ketamine in a propofol-ketamine co-induction?

To reduce the risk of ketamine-induced emergence reactions and dysphoria during induction.

What are the two categories of inhalant anesthetic agents based on physical state?

Volatile liquids (vapors) and compressed gases.

Name four volatile liquids commonly used as inhalants.

Halothane, isoflurane, sevoflurane, and desflurane.

Name two compressed gases used as inhalants.

Nitrous oxide and xenon.