General Anesthetics Flashcards
Two groups of General Anesthetics
1) Inhalation anesthetics
2) Intravenous anesthetics
General Anesthrics
drugs that produce UNCONSCIOUSNESS and a lack of responsiveness to all PAINFUL STIMULI
Analgesis
refers to loss of sensitivity to pain
Anesthetic
refers to loss of PAIN but also loss of all other SENSATIONS, and loss of CONSCIOUSNESS
Balanced Anesthesia
combining drugs to accomplish what can’t be achieved by inhalation anesthetics alone
what agents are use to achieve balanced anesthesia
1) Propofol and Short-Acting Barbiturates (inducing anesthesia)
2) Neuromuscular blocking agents (muscle relaxation)
3) Opioids and nitrous oxide (analgesia)
Anesthetics work by
1) ENHANCING transmission at inhibitory synapses
2) DEPRESSING transmission at excitatory synapses
What is the principle inhibitory transmitter in CNS
GABA
What is GABA
generalized inhibition of CNS function
Nitric Oxide do
blocking actions of N-methyl-D-Aspartate (NMDA)
- an excitatory neuron
MAC
minimum alveolar concentration
what is Minimum Alveolar Concentration
index of minimum concentration of drug in alveolar air
- that will produce IMMOBILITY IN 50% of patients exposed to painful stimuli
do most agents have a high or low MAC
most have a low mac
nitric Oxide MAC
high MAC
- surgical anesthesia cant be achieved with nitric oxide alone
Agent Uptake of ihaltion anesthetics
major determinant (outside of lung issues) is [aesthetic] in inspired air/ greater = faster uptake
adverse effects of inhalation anesthetics
major concern:
respiratory/ cardiac depression
- doeses 2 - 4 times greater than needed can cause lethal depression
Aspiration
- reflexes that prevent aspiration of GI tract contents into lungs are absent in state of anesthesia
Preanesthetics Medication purposes
1) reducing anxiety
2)produce perioperative amnesia
3) relieving pre and post operative pain
What are preanesthrtic medications
Benzodiazepines
Opiods
Alpha2-andrenergic agnonists
benzodiazepines
reduce anxiety and promote amnesia
opiods
relieve pain
supress cough
alpha2-andrenergic agonists
reduce pain
cause sedation
anesthesiologists
physicians
anesthestists
nurses
2 basic categories of inhalation anesthetics
1) gases (gaseous state at atmospheric pressure)
2) volatile liquids ( lipuid at atmospheric pressure but converted to vapour for administration
Individual inhalation anesathetics
Isoflurane
Nitric Oxide
isoflurane
what is it
adverse effects
proteo type for volatile inhalation anesthetics
adverse: hypotension, respiratory depression
Nitric Oxide
very low anesthetic potency
high analgesic potency
most widely used inhalation agents
Benefits of iv anesthetics
1) allow inhaltion disage to be reduced
2) produce effects that cant be achieved by inhalation agent alone
Short acting barbiturates
Methohexital
Benzodiazepines: Diazepan
Methohexital
effective, but production ceased in 2011 because of its use in human execution
Benzodiazepines: Diazepam
on occasion causes severe respiratory depression
- emergency respiratory support should be immediately available
other iv anesthetics
Propofol
Ketamine
Propofol
most widely used ivs
promotes release of GABA = generalized CNS depression
propofol adverse effects
narrow therapeutic range
ketamine
produces dissociative anesthesia
used for minor surgical/ diagnostic procedures
- changing of burn dressing
