Final answer:
Barbiturates, propofol, etomidate, opioids (except sufentanil), and benzodiazepines are CNS depressants that work by enhancing GABA. Ketamine is a dissociative anesthetic that blocks NMDA receptors. Dexmedetomidine is a selective alpha-2 adrenergic agonist used for sedation. Volatile anesthetics enhance GABA and produce unconsciousness and analgesia.
Step-by-step explanation:
1) Barbiturates, propofol, etomidate, opioids (except sufentanil), and benzodiazepines are all CNS depressants and have similar effects on the brain. They work by enhancing the inhibitory neurotransmitter GABA (gamma-aminobutyric acid), which leads to sedation, relaxation, and unconsciousness. They can also cause respiratory depression and can be dangerous when used in overdose with other CNS depressants.
2) Ketamine is a dissociative anesthetic that works by blocking the NMDA receptors in the brain. This results in a state of dissociation, where the patient may feel detached from their body and have hallucinations. Ketamine also has analgesic properties and can cause cardiovascular stimulation.
3) Dexmedetomidine is a selective alpha-2 adrenergic agonist that is used for sedation in the ICU. It works by reducing the release of norepinephrine, which leads to sedation, anxiolysis, and analgesia. Dexmedetomidine has minimal effects on respiratory function and does not cause significant cardiovascular depression.
4) Volatile anesthetics such as desflurane, isoflurane, and sevoflurane are inhaled anesthetics that work by enhancing the inhibitory neurotransmitter GABA. They produce a state of unconsciousness, amnesia, and analgesia. Volatile anesthetics also have cardiovascular effects, such as vasodilation and myocardial depression.