General Anesthetics Flashcards
(35 cards)
Sodium thiopental mechanism of action (3):
- GABAa activator.
- Decreases cerebral oxygen utilization, blood flow, and intracranial pressure.
- Drop in BP because of vasodilation (reduction in preload).
Sodium thiopental uses:
- Induces anesthesia.
- Has been tried as a protective agent against cerebral ischemia.
Sodium thiopental side effects:
- *Produces hypotension, hangover effect.
- Respiratory depression
Propofol mechanism of action (3):
- GABAa activator.
- Results in a decrease in cerebral oxygen utilization, blood flow, and intracranial pressure.
- Drop in BP because of vasodilation (reduction in preload), AND depression of myocardial contractility.
Propofol uses:
- Induces and maintains anesthesia.
- Antiemetic.
- Has a shorter half-life than thiopental; used when a rapid return to normal mental status is desired.
Propofol side effects:
- Hypotension and respiratory depression (more than thiopental).
- Pain at injection site.
- Can produce excitation during induction.
Etomidate mechanism of action:
Activates GABAa receptors through allosteric effects.
Etomidate use:
Primarily used to induce anesthesia in patients at risk for hypotension (less CV effects than thiopental and propofol).
Etomidate side effects:
- Significant nausea and vomiting.
- Increased post-surgical mortality due to suppression of the adrenocortical stress-response.
Ketamine use:
-Reserved for patients with bronchospasm, and children undergoing short, painful procedures.
Ketamine mechanism of action:
- NMDA receptor antagonist.
- Produces a hypnotic state called “dissociative anesthesia”, characterized by profound analgesia, unresponsiveness to commands (even though eyes can be open), amnesia, spontaneous respiration, *bronchodilation.
Ketamine side effects:
- Emergence delirium.
- Nystagmus, salivation, lacrimation, spontaneous limb movements, and increased muscle tone.
- Increased BP due to indirect sympathomimetic activity.
Midazolam mechanism of action:
- Short acting benzodiazepine.
- GABAa activator. Metabolized by hydroxylation to an active metabolite.
Midazolam use:
- Used for conscious sedation during minor surgical procedures (wisdom teeth extraction).
- Slower induction time and longer duration than thiopental.
Midazolam side effects:
- Respiratory arrest.
- Use with caution in patients with movement disorders, bipolar disorder.
Isoflurane mechanism of action:
Inhaled GABAa activator with moderate blood:gas partition coefficient.
Isoflurane uses:
- Used to induce and maintain anesthesia.
- Co-administration with NO allows for reduction in the dose.
Isoflurane side effects:
- Airway irritant.
- Respiratory depressant, increases PaCO2.
- Myocardial depression. Arrhythmias (sensitizes the heart to catecholamines).
- Dilates cerebral blood vessels, increasing intracranial pressure. Dilates coronary vessels.
Desflurane mechanism of action:
- Inhaled GABAa activator with low blood:gas partition coefficient (rapid induction and recovery).
- Produces direct skeletal muscle relaxation.
Desflurane uses:
-Used for maintenance of general anesthesia in outpatient surgeries.
Desflurane side effects:
- Airway irritant - causes coughing and bronchospasms.
- Respiratory depressant, increases PaCO2.
- Myocardial depression. Arrhythmias (sensitizes the heart to catecholamines).
- Dilates cerebral blood vessels, increasing intracranial pressure. Dilates coronary vessels.
Sevoflurane mechanism of action:
-Inhaled GABAa activator with low blood:gas partition coefficient (rapid induction and recovery).
Sevoflurane uses:
- Used for maintenance of general anesthesia in inpatient and outpatient surgeries.
- Little irritation to airways.
Sevoflurane side effects:
- Less irritation to airways, less respiratory depression.
- Myocardial depression.
