Anesthetics Flashcards
What are the inhaled general anesthetics?
- nitrous oxide
- isoflurane
- enflurane
- desflurane
- sevoflurane
What are the intravenous general anesthetics?
- propofol
- etomidate
- ketamine
What are the adjuncts for general anesthetics?
- midazolam
- Fentanyl
- Dexmedetomidine
Why are general anesthetics a very dangerous group of drugs?
narrow therapeutic index and extremely fast acting.
What term is used to describe general anesthetics?
controlled death
When was the first successful demonstration of the ability of a patient to be anaesthetized? what was used?
1846 by william morton.
diethyl ether vapor
What are the three requirements for a patient to achieve an anesthetic state?
- amnesia (depress activity in hippocampus)
- immobility - inhibit conscious or nerve reflex
- attenuation of autonomic
What dose the term balanced anesthesia mean?
use of multiple classes of drugs to achieve the desired depth of anesthesia
What drugs are used for pre-op sedation?
barbiturates, diazepam, midazolam.
What drug is used for pre-op to reduce risk of bradyarrhythmia?
atropine
What drug is used for pre-op to prevent vomiting?
ondansetron
What drug is used for pre-op reduction of regurgitation?
ranitidine
What drugs are used to induce anesthesia and why?
intravenous GA because they are faster acting than inhaled GA
What drugs are used for maintenance of anesthesia?
inhaled GA, can be fine tuned to the dose.
What drug is used in addition to other inhaled GA to allow for lower amounts of other GA used?
nitrous oxide
What drug is given to reduce dose of GA and block noxious stimulus reflex?
fentanyl
What drug is used as an neuromuscular junction blocking agent for endotracheal intubation?
succinylcholine
What rebound effect do GAs have?
tachycardia and hypertension
What does emergence excitement mean?
a condition where the half conscious patient exhibits restlessness, crying, moaning, and extreme thrashing.
What drug can be given post-op to reduce shivering threshold?
meperidine.
All inhaled GAs are what, except for nitrous oxide which is a gas.
volatile liquids
What determines the rate of aesthetic induction/recovery?
rate of GA diffusion from lung - blood- CNS
The faster the effects of inhaled GA wear off post-surgery….
the faster the patient can start to recover and spend less time in recovery room.
Drugs with poor water soluility come to equilibrium?
rapidly, thus rapid recovery
Drugs with high solubility come to equilibrium?
slowly, thus slow recovery
What measures the water solubility?
blood/gas partition coefficient
What is used to measure potency?
MAC minimum alveolar concentration.
MAC is defined as?
concentration of inhaled GA needed for 50% of patients to NOT respond to pain.
What is the rule of thumb when comparing solubility to potency?
The greater the Lipid solubility, the greater the potency.
The speed of induction _________ related to blood solubility while potency is ________ to lipid solubility.
Inversely
Proportional
How do GAs inhibit neuronal acitivity?
- neuronal hyperpolarization
- inhibit excitatory synapses (NMDA)
- enhance inhibitory synpases (GABA)
What are the components of the machines used for inhaled GAs?
oxygen, vaporizer, ventilator, CO2 absorber (soda lime)
How is depth of anesthesia measured?
By computers that analyze patient EEG. BIS bispectral index, where 100 is awake and 0 is deep coma.
What is used to induce analgesia in dentist offices?
Nitrous oxide
What is nitrous oxide solubility in water? in lipids?
Low water solubility - Fast acting
Low lipid solubility - low potency
What is diethyl ether solubility in water? in lipids?
High water solubility - slow acting
High lipid solubility - very potent
What drug can result in spontaneous combustion on the operating table?
cyclopropane
This drug has no pungent odor and can cause hepatitis.
Halothane.
High water solubility - slow acting
High lipid solubility - potent
This drug has a sweet odor and can produce electrical seizures.
Enflurane
If a blood:gas partition coefficient is = 1.8 what does this mean?
The drug is soluble in water/blood and therefore is slow acting.
This drug is eliminated unchanged via the lungs.
Isoflurane, Desflurane, Sevoflurane
This drug is the preferred GA for neurosurgery. It produces vasodilation in cerebral vasculature, but does what in the brain?
Isoflurane
Decrease metabolic rate in brain
This drug is an irritating gas and must be use IV to induce anesthesia.
Desflurane
What can interact with sevoflurane?
Baralyme CO2 absorber that can cause heat, and burn airways.
What drug is preferred for patients prone to myocardial ischemia?
Sevoflurane
What drug reacts with soda lime to produce Compound A causing short term renal damage?
Sevoflurane
This drug must be used with caution in patients with high triglyceride levels due to low water solubility?
Propofol
This drug is the most common induction agent of anesthesia.
Propofol
This drug can be used for patient prone to vomiting due to its anti-emetic properties.
Propofol
This drug is used for patients at risk for hypotension.
Etomidate, Ketamine
This drug is used for induction and maintenance of anesthesia.
Etomidate
This drug can cause nausea and vomiting and inhibits adrenal gland enzymes.
Etomidate
This drug produces profound analgesia.
Ketamine
This drug is used in battlefields and in veterinary medicine.
Ketamine
This drug causes a modest decrease in ventilation rate and is potent bronchodilator.
Ketamine
These drugs are used for pre-op sedation and amnesia.
Midazolam>diazepam>lorazepam
Which of the benzodiazepines is water soluble, no injection pain, and preferred?
Midazolam
What drug is used to minimize vascular reflex to noxious, painful stimuli?
Fentanyl
This drug is used in hostage/terrorist action to incapacitate individuals.
Fentanyl
This drug is used to reduce post-op shivering.
Meperidine
This drug is an alpha2 agonist used in critically ill adults for sedation.
dexmedetomidine
This drug does not change the ventilation rate.
dexmedetomidine
This drug is useful in non-intubated patients.
dexmedetomidine
How do GAs cause hypothermia?
Cause vasodilation that faclitates body heat loss.
What is the treatment for hypothermia?
Warming methods, such as heating of air, heated beds, water-filled garments.
What is malignant hyperthermia?
Core body temperature rises over 42C due to uncontrolled muscle activity.
What specifically causes malignant hyperthermia?
ryanodine calcium channels do not close resulting in uncontrolled muscle contractions leading to heat generation.
Fatigued myocytes lyse releasing potassium resulting in fatal cardiac events.
This drug is a ryanodine receptor inhibitor, used to treat spasms and spastic disorders.
dantrolene
