Podcast
Questions and Answers
Which induction agent is known for its distinct antiemetic properties?
Which induction agent is known for its distinct antiemetic properties?
- Ketamine
- Propofol (correct)
- Etomidate
- Midazolam
What is the significant disadvantage of using etomidate, particularly as an infusion?
What is the significant disadvantage of using etomidate, particularly as an infusion?
- Adrenal suppression (correct)
- Hypotension
- Hyperactivity
- Respiratory depression
Which drug provides unequaled cardiovascular stability as an induction agent?
Which drug provides unequaled cardiovascular stability as an induction agent?
- Propofol
- Midazolam
- Ketamine
- Etomidate (correct)
What are the five principal effects of benzodiazepines mentioned in the text?
What are the five principal effects of benzodiazepines mentioned in the text?
What is the primary action of barbiturates at the GABA A receptor?
What is the primary action of barbiturates at the GABA A receptor?
Which setting is etomidate unlikely to be used in?
Which setting is etomidate unlikely to be used in?
What effect does etomidate have on cerebral blood flow?
What effect does etomidate have on cerebral blood flow?
What is a potential side effect of etomidate induction?
What is a potential side effect of etomidate induction?
Which etomidate derivative may not inhibit steroidogenesis?
Which etomidate derivative may not inhibit steroidogenesis?
What is the unique structure of midazolam among benzodiazepines?
What is the unique structure of midazolam among benzodiazepines?
How do benzodiazepines act on the GABAA receptor?
How do benzodiazepines act on the GABAA receptor?
What is true regarding the metabolism of lorazepam?
What is true regarding the metabolism of lorazepam?
Which statement is true regarding age and midazolam requirement?
Which statement is true regarding age and midazolam requirement?
In what setting is etomidate NOT a useful induction agent?
In what setting is etomidate NOT a useful induction agent?
What is the primary effect of benzodiazepine bound by GABAA receptor?
What is the primary effect of benzodiazepine bound by GABAA receptor?
What is a potential side effect of etomidate induction?
What is a potential side effect of etomidate induction?
Which patient population requires a 25-50% reduction in dose of propofol?
Which patient population requires a 25-50% reduction in dose of propofol?
What is the recommended dosing range of propofol for maintenance of anesthesia?
What is the recommended dosing range of propofol for maintenance of anesthesia?
Which clinical use of propofol is valued due to its rapid effect-site equilibration and short context-sensitive half-time?
Which clinical use of propofol is valued due to its rapid effect-site equilibration and short context-sensitive half-time?
What is the bolus dose of propofol for postoperative nausea and vomiting?
What is the bolus dose of propofol for postoperative nausea and vomiting?
What organ system effect does propofol have on intracranial pressure?
What organ system effect does propofol have on intracranial pressure?
What is the effect of propofol on evoked potentials in the auditory system?
What is the effect of propofol on evoked potentials in the auditory system?
Which cardiovascular effect is associated with propofol administration?
Which cardiovascular effect is associated with propofol administration?
In which patient population is propofol-induced hypotension more common?
In which patient population is propofol-induced hypotension more common?
What is the mechanism of neuroprotection associated with propofol?
What is the mechanism of neuroprotection associated with propofol?
What is the risk of bradycardic death associated with propofol?
What is the risk of bradycardic death associated with propofol?
What is the mechanism of action of barbiturates at low concentrations?
What is the mechanism of action of barbiturates at low concentrations?
Which barbiturate became the preferred intravenous barbiturate due to its rapid onset and short duration?
Which barbiturate became the preferred intravenous barbiturate due to its rapid onset and short duration?
What is the main form of hepatic metabolism for barbiturates?
What is the main form of hepatic metabolism for barbiturates?
In pharmacokinetics, what results in the termination of action of a bolus dose of barbiturates?
In pharmacokinetics, what results in the termination of action of a bolus dose of barbiturates?
Which receptors do barbiturates also act at, in addition to GABAA and glutamate receptors?
Which receptors do barbiturates also act at, in addition to GABAA and glutamate receptors?
Which barbiturate may lead to accumulation of the active metabolite pentobarbital at high doses?
Which barbiturate may lead to accumulation of the active metabolite pentobarbital at high doses?
What is the main basis for recommending that barbiturates be avoided in porphyria?
What is the main basis for recommending that barbiturates be avoided in porphyria?
What is the primary metabolite of midazolam?
What is the primary metabolite of midazolam?
Which drug inhibits the hepatic clearance of midazolam?
Which drug inhibits the hepatic clearance of midazolam?
Which benzodiazepine has a metabolism that is relatively unaffected by inhibition of cytochrome P-450 or changes in hepatic function?
Which benzodiazepine has a metabolism that is relatively unaffected by inhibition of cytochrome P-450 or changes in hepatic function?
Which benzodiazepine has a lower lipid solubility resulting in a delayed onset of effect in the central nervous system (CNS)?
Which benzodiazepine has a lower lipid solubility resulting in a delayed onset of effect in the central nervous system (CNS)?
In children, what is the recommended dosage range for oral premedication with midazolam?
In children, what is the recommended dosage range for oral premedication with midazolam?
Which benzodiazepine is known for its reliable amnesia and slower onset compared to thiopental or propofol?
Which benzodiazepine is known for its reliable amnesia and slower onset compared to thiopental or propofol?
What effect do benzodiazepines have on cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2)?
What effect do benzodiazepines have on cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2)?
How does flumazenil work?
How does flumazenil work?
What is a known use for flumazenil?
What is a known use for flumazenil?
Which of the following is a potential cardiovascular effect of propofol?
Which of the following is a potential cardiovascular effect of propofol?
What is a potential respiratory effect of propofol?
What is a potential respiratory effect of propofol?
Which of the following is a potential side effect of propofol?
Which of the following is a potential side effect of propofol?
What is a distinguishing feature of Fospropofol (AQUAVAN) compared to propofol?
What is a distinguishing feature of Fospropofol (AQUAVAN) compared to propofol?
What is a potential disadvantage associated with Fospropofol (AQUAVAN) administration?
What is a potential disadvantage associated with Fospropofol (AQUAVAN) administration?
What is a characteristic of etomidate's mechanism of action?
What is a characteristic of etomidate's mechanism of action?
Which statement accurately describes etomidate's pharmacokinetics?
Which statement accurately describes etomidate's pharmacokinetics?
What is an advantage of etomidate's preparation in a lipid emulsion?
What is an advantage of etomidate's preparation in a lipid emulsion?
What best describes the mechanism of action of etomidate?
What best describes the mechanism of action of etomidate?
What is the dominant cardiovascular effect of ketamine in a patient with an intact autonomic nervous system and adequate catecholamine stores?
What is the dominant cardiovascular effect of ketamine in a patient with an intact autonomic nervous system and adequate catecholamine stores?
Which anesthetic agent, as an adjunct to general anesthesia, markedly reduces MAC but is associated with a high incidence of bradycardia?
Which anesthetic agent, as an adjunct to general anesthesia, markedly reduces MAC but is associated with a high incidence of bradycardia?
Which of the following anesthetic agents is a GABA Agonist Sedative-Hypnotic?
Which of the following anesthetic agents is a GABA Agonist Sedative-Hypnotic?
What is the preparation of propofol that requires the presence of a preservative to prevent bacterial growth?
What is the preparation of propofol that requires the presence of a preservative to prevent bacterial growth?
Which anesthetic agent has minimal hysteresis, rapid termination of action due to redistribution, and high clearance relative to other induction agents?
Which anesthetic agent has minimal hysteresis, rapid termination of action due to redistribution, and high clearance relative to other induction agents?
What is the expected elimination half-life of propofol?
What is the expected elimination half-life of propofol?
What is the primary clinical use for propofol?
What is the primary clinical use for propofol?
What is the recommended dosing for healthy adults for propofol induction of anesthesia?
What is the recommended dosing for healthy adults for propofol induction of anesthesia?
Study Notes
Induction Agents and Their Properties
- Ondansetron is an induction agent characterized by distinct antiemetic properties.
- Etomidate's significant disadvantage includes suppression of steroidogenesis, impacting adrenal function during infusion.
- Propofol provides unparalleled cardiovascular stability as an induction agent.
Benzodiazepines and Their Mechanism
- Five principal effects of benzodiazepines: anxiolysis, sedation, amnesia, muscle relaxation, and anticonvulsant effects.
- Barbiturates primarily act at the GABA A receptor, enhancing inhibitory neurotransmission.
- Benzodiazepines enhance the opening of GABAA receptor channels, increasing chloride influx.
- Midazolam has a unique structure with a nitrogen atom in its ring, differentiating it among benzodiazepines.
Metabolism and Dosage Considerations
- Lorazepam's metabolism is primarily through conjugation, making it less affected by liver dysfunction.
- Midazolam requirements decrease with age, as older patients typically need lower dosages.
- Propofol infusion may require a 25-50% dose reduction in the elderly or those with compromised hepatic function.
- Recommended dosing range for propofol maintenance of anesthesia is typically 100-200 mcg/kg/min.
Propofol Properties and Effects
- Propofol is valued for its rapid effect-site equilibration and short context-sensitive half-time.
- A bolus dose of propofol for postoperative nausea and vomiting is usually around 10-20 mg.
- Propofol decreases intracranial pressure and has a beneficial effect on auditory evoked potentials.
- Propofol administration is associated with hypotension, especially in patients with compromised cardiovascular function.
Barbiturates: Mechanisms and Risks
- Barbiturates' low-concentration mechanism of action involves increasing duration of GABA A receptor activation.
- Thiopental is the preferred intravenous barbiturate due to its rapid onset and short duration of effects.
- Hepatic metabolism is the main pathway for barbiturates, primarily through oxidative processes.
- Accumulation of pentobarbital may occur at high doses of its respective barbiturate.
Respiratory and Cardiovascular Effects
- Benzodiazepines reduce cerebral metabolic rate of oxygen (CMRO2) and cerebral blood flow (CBF).
- Flumazenil acts as a benzodiazepine antagonist, reversing sedation effects; useful in overdose situations.
- Propofol may cause respiratory depression and hypotension, but has a minimal effect on the central nervous system's excitability.
Fospropofol Considerations
- Fospropofol (AQUAVAN) is distinguished from propofol by being water-soluble and having a slower onset.
- A potential disadvantage of Fospropofol includes the risk of delayed respiratory depression.
Etomidate and Its Use
- Etomidate's mechanism of action involves enhancing GABAergic transmission, providing rapid sedation without significant cardiovascular effects.
- Unlikely to be used in emergency settings due to the potential risk of adrenal suppression.
- The lipid emulsion formulation of etomidate aids in reducing pain on injection.
Ketamine's Cardiovascular Effects
- Ketamine exhibits dominant cardiovascular stimulation in patients with intact autonomic and catecholamine stores.
Induction Dosage and Administration
- Clinically, propofol has an expected elimination half-life of around 30-60 minutes post-infusion.
- Recommended dosage for propofol induction in healthy adults ranges from 1.5-2.5 mg/kg.
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