32 Questions
What is Methohexital used for in low doses?
To induce seizure discharges in temporal lobe epilepsy
What is the effect of intravenous induction agents on the respiratory system?
Dose-dependent respiratory depression
How long does apnea typically last after barbiturate induction?
Around 30 seconds or less
What happens to cardiac index due to anesthetic effects?
It remains unchanged or is reduced
What is the effect of anesthetics on sympathetic outflow from the CNS?
It decreases significantly
Following acute brain injury, what do barbiturates fail to demonstrate superiority over other techniques in doing?
Decreasing ICP
What is the maximum decrease in CMRO2 achievable with barbiturates?
50-55%
In which scenario have barbiturates been found to be contraindicated?
Following resuscitation from cardiac arrest
What is a paradoxical effect of barbiturates at lower doses?
Increased seizure activity
What is a proposed mechanism of the neuroprotective effect of barbiturates?
Blockade of excitatory amino acids
Which medication reduced lipid peroxidase but did not spare ultrastructure injury in spinal cord injury studies?
Propofol
What is the mechanism of action of thiopental and propofol in reducing spinal cord injury?
Antioxidant activity and free radical scavenging
Which factor does Propofol-induced hypotension in elderly patients depend on?
Hypovolemic states
What is a dose-dependent effect of thiopental and propofol in cardioprotection?
Myocardial protection
Which medication reduces vagally mediated and methacholine-induced bronchoconstriction?
Propofol
Which effect is NOT true about propofol in the context of spinal cord injury?
Increases sympathetic activity
Which benzodiazepine has a shorter half-life and increased context-sensitive half-time compared to propofol?
Midazolam
In patients with reduced intracranial compliance, benzodiazepines like midazolam are generally considered acceptable for?
Induction agent
Which effect do benzodiazepines like midazolam exhibit by decreasing the ventilatory response to CO2?
Central respiratory depression
Which clinical use is NOT associated with benzodiazepines as mentioned in the text?
Treatment of hypertension
What is the primary reason for the modest decrease in blood pressure observed with the use of benzodiazepines like midazolam?
Increased SVR
According to the information provided, which organ system is negatively impacted by benzodiazepines through decreased muscular tone in the upper airway?
Respiratory
Which receptor does ketamine inhibit the release of glutamate from the presynaptic nerve terminal?
NMDA receptor
What is the major active metabolite of ketamine formed via hepatic microsomal enzymes?
Norketamine
What is the primary effect of ketamine in inducing analgesia?
Activation of NMDA receptors
Which organ system shows decreased salivation and reduced incidence of emergence reactions with the S(+) isomer of ketamine?
Digestive system
What is the primary characteristic of the 'dissociative state' induced by ketamine?
Consciousness with amnesia
Which route of administration for ketamine results in the highest bioavailability?
Nasal
What is the primary concern when using ketamine for induction in patients with known severe cardiac valvular disease?
Cardiac arrhythmias
Which aspect of biochemical pharmacokinetics does ketamine exhibit a brief duration of action?
Redistribution
What is the primary concern with ketamine induction in individuals with elevated intracranial pressure (ICP)?
Cerebral vasodilation
What is the therapeutic benefit of ketamine in postoperative sedation and analgesia?
Opioid sparing effect
Explore the mechanisms and effects of Thiopental and Propofol in reducing lipid peroxidation and altering ultrastructure injury in spinal cord injury studies. Learn about the antioxidant activities and cardiovascular effects associated with these drugs.
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