Anaesthetics: Properties and Uses

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Questions and Answers

What type of anaesthesia can be achieved by combining nitrous oxide with fentanyl and droperidol?

Neurolept anaesthesia

What is the shortest acting opioid, and how is it metabolized?

Remifentanil, metabolized by esterases

What is the primary mechanism of action of droperidol?

D2 receptor blocker

What is the effect of adding sodium bicarbonate to local anesthetics?

Accelerates onset of action Signup and view all the answers

What is a potential allergenic compound formed during the metabolism of ester local anesthetics?

Para-aminobenzoic acid (PABA) Signup and view all the answers

What is the primary adverse effect of local anesthetics?

Systemic absorption of toxic amounts Signup and view all the answers

What is the order of nerve function loss due to local anesthetics?

Sympathetic function, pinprick sensation and temperature, and finally motor function Signup and view all the answers

What is alfentanil used for?

Day care surgery and total intravenous anaesthesia Signup and view all the answers

Which local anesthetic is used intravenously in the treatment of cardiac arrhythmias?

Lidocaine Signup and view all the answers

What is unique about cocaine as a local anesthetic?

It is a vasoconstrictor, has sympathomimetic effect, and should not be given intravenously or with adrenaline. Signup and view all the answers

Why is procaine the local anesthetic of choice in malignant hyperthermia?

No specific reason is given in the content, but procaine is the preferred choice in malignant hyperthermia. Signup and view all the answers

How does cocaine differ from other local anesthetics in terms of its effect on blood pressure?

It increases blood pressure. Signup and view all the answers

What is unique about the metabolism of cocaine compared to other ester local anesthetics?

It is metabolized in the liver, not by pseudocholinesterase. Signup and view all the answers

What is the primary difference in the mechanism of action of cocaine compared to other local anesthetics?

It has a sympathomimetic effect due to inhibition of nor-adrenaline reuptake. Signup and view all the answers

What is the site of action of dissociative anaesthesia, responsible for the effect seen while recovery from anaesthesia?

Thalamocortical junction Signup and view all the answers

Which anaesthetic has the maximum analgesic effect among anaesthetics?

T Signup and view all the answers

Which anaesthetic is an excellent choice for asthmatics?

Propofol Signup and view all the answers

What is the benefit of using propofol infusion during maintenance of anaesthesia?

It can be supplemented with intravenous opioids and neuromuscular blockers as needed Signup and view all the answers

Why is etomidate the agent of choice for aneurysm surgeries and cardiac disease?

It does not interfere with cardiovascular functions Signup and view all the answers

Which benzodiazepine is commonly used in pre-anaesthetic medication?

Lorazepam Signup and view all the answers

What is the most potent opioid used in anaesthesia?

Sufentanil Signup and view all the answers

What is the use of midazolam in anaesthesia?

It is used for day care surgery Signup and view all the answers

Study Notes

Anaesthetics

Thalamocortical junction is the site of action for dissociative anaesthesia
Analgesic with maximum potency among anaesthetics
Can be given in full stomach
Increases all pressures
NMDA antagonist
Excellent for asthmatics

Propofol

Most frequently administered drug for induction of anesthesia
Alternative to inhaled anesthetics for maintenance of anesthesia
Common choice for sedation in monitored anesthesia care
Can be used for total intravenous anesthesia (TIVA)
Intravenous anaesthetic of choice in patients with malignant hyperthermia

Etomidate

Does not interfere with cardiovascular functions
Agent of choice for aneurysm surgeries and cardiac disease
Causes minimal respiratory depression
Maximum incidence of nausea and vomiting

Benzodiazepines

Important benzodiazepines: diazepam, lorazepam, and midazolam
Not analgesic agents
Possess muscle relaxing and anticonvulsant properties
Lorazepam is commonly used in pre-anaesthetic medication
Midazolam is used for day care surgery
Can cause sedation and anterograde amnesia

Opioids

Fentanyl, alfentanil, sufentanil, and remifentanil are used in anaesthesia
100 times more potent than morphine
Sufentanil is the most potent opioid
Possess strong analgesic activity
Can lead to post-operative muscle rigidity
Alfentanil is used for day care surgery and total intravenous anaesthesia
Remifentanil is the shortest acting opioid

Neuroleptic Agents

Neurolept anesthesia combines neuroleptic and analgesic to produce sedation, analgesia, and amnesia
Droperidol is a D2 receptor blocker used with fentanyl to produce neurolept analgesia and anaesthesia
Can produce extrapyramidal symptoms

Local Anesthetics

Applied locally and block nerve conduction
Loss of sympathetic function occurs first, followed by loss of pinprick sensation and temperature, and finally, motor function
Effect is reversible, with complete recovery of nerve function
Commonly used for minor surgical procedures, often in combination with vasoconstrictors
Onset of action may be accelerated by the addition of sodium bicarbonate
Metabolism of ester local anesthetics leads to formation of para-aminobenzoic acid (PABA), which is thought to be allergenic

Important Facts

Lidocaine is used intravenously in the treatment of cardiac arrhythmias
Cocaine is an effective local anesthetic with sympathomimetic effect
Cocaine should never be given by intravenous route or with adrenaline
Procaine is the local anaesthetic of choice in malignant hyperthermia

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Description

This quiz covers the properties and uses of different anaesthetics, including dissociative anaesthesia, analgesic potency, and suitability for various medical conditions. Test your knowledge of thalamocortical junction, NMDA antagonists, and total intravenous anesthesia.