Anaesthetics Flashcards
Define conscious sedation.
Use of small amounts of anaesthetics and benzodiazepines to produce a sleepy like state - maintain verbal contract but feel comfortable.
Give two benefits of having a low blood:gas partition.
Name an anaesthetic known for having a low blood gas partition.
Faster induction and faster recovery
Desflurane.
What does a greater oil:gas partition indicate?
Greater potency (smaller amount of the drug is needed to produce anaesthesia)
How does MAC relate to potency?
MAC is inversely proportion to potency so a greater MAC indicates a reduced potency as more drug is needed to produce anaesthia in 50% of subjects.
Give some factors that increase MAC.
Decrease?
Pregnancy Hyperthermia Alcoholism Central stimulants Infants (higher mac)
Other anaesthetics and sedative usage
Opioid usage
Hypothermia
Increased age
Why is nitrous oxide often added to other volatile agents?
Decreases the MAC and therefore increases potency of the other drug and reduces the dose of the drug required.
N2O itself has a low side effect prolife and since it allows us to reduce dosage of the other anaesthetic we can have reduced side effects of the other anaesthetic.
Contrast the effects of group 1 anaesthetics (propafol etc) vs group 2 (Ketmaine, N2O, cyclopropane and Xenon).
MOA of group 2?
Group 1 - good at unconsciousness but less analgesia and immobility
(Typically used in induction)
Group 2 - significant analgesia but reduced consciousness and immobility
(Typically used in maintenance)
NMDA inhibition (reduced Ca influx) (2 pore domain) K+ channel (promote opening of these - decreasing neuronal excitibility)
Give two side effects of propafol.
Give two side effects of barbiturates.
One side effect of etomidate.
These are both class one agents
Respiratory depression
Hypotension
Bronchospasm (cough)
Respiratory depression
Adrenal supression
Myoclonus.
Give adverse effects of ketmaine.
N2O and Cyclopropane?
Xenon?
Hypertension
Tachycardia
Hypersalivation
Emergence phenomena (Delirium, vivid dreams, hallucinations)
Dizziness, nausea and vomiting
very few side effects.
Name two 3rd group anaesthetics.
(Volatile Halogenated)
What is the main effect of this class?
Give two general adverse effects of this class.
Give two specific to halothane.
Halothane
Desflurane
More potent at producing immobility. Diverse MOA (all three previously talked about)
Both produce hypotension and reduced cardiac output
halothane - cardiac arrythmias and hepatotoxicity
Name the three main IV agents.
Distinguish between their onset of action.
Propafol (rapid)
Barbiturates (rapid)
Ketamine (slower)
What type of fibres do local anaesthetics mainly act on?
Give two side effects of local anaesthetics.
Small myelinated fibres.
Confusion and dizziness
Headache, CNS depression also
Vasodilation and myocardial depression
Why is bupivicaine more used in long surgeries?
What about it gives it, its longer duration of action?
Long duration of action.
Amide link and high degree of protein binding.
