Flashcards in Anesthesia and PD Deck (25):
What are the four cardinal signs/symptoms of Parkinson's Disease?
1. Tremor (gets better with a directed movement)
4. Postural Instability
What does rigidity indicate?
Pathology in the contralateral basal ganglia
What is the most common way to differentiate between PD and atypical parkinsonism?
give L-DOPA and look for patient improvement
Why do we adminsiter carbidopa with Levo-DOPA during PD therapy?
helps prevent the side effects of L-DOPA therapy that make it impossible to use: prevents the conversion of L-DOPA to dopamine in the bloodstream (which causes terrible nausea and other really unpleasant side effects). q
Other than L-DOPA and dopamine receptor agonists, what kinds of drugs can we use to treat Parkinson's disease?
MAO inhibitors to prevent dopamine degradation- selegiline and resagiline
or COMP inhibitor (just 1)
What should I be cautious about in terms of barbituate administration?
contraindicated in patients with acute intermitant porphyria
What should I be careful about with propofol?
supports bacterial growth and can cause sepsis
potential allergy issues (maybe)
not terribly forgiving
What is one advantage of propofol?
low context-sensitive half time
What should I be careful about with ketamine?
intracranial pressure and pulmonary artery pressure: careful in trauma pts or pts with weak arteries
(can be used in pregnant women, esp. with an emergency C-section)
What is the only anesthetic that mimics sleep?
What is one of the most important and underappreciated goals of anesthesia?
reduce surgical stress response: long-term implications
Where does anesthesia act?
brain AND spinal cord
spinal cord may be especially important for restricting movement.
What is the myer-overton hypothesis and what are the problems with it?
hypothesis: anesthesia works by changing the membrane, based on correlation between lipid solubility and potency and based on the fact that efficacy is reduced under conditions of high atmospheric pressure. Problem is that the correlation between lipid soulbuility and potency does not always hold true, and high atmospheric pressure increases stress on the body... a condition that ALWAYS decreases the efficacy of anesthesia
What are three advantages of inhalational anesthesia?
easy to administer
easy to eliminate
little metabolism to toxic substances
What determines brain concentration of an inhaled anesthesia? What factors determine the speed with which a patient is roused following inhalational anesthesia?
Alveolar concentration determines brain concentration.
Tissue distribution in vascular beds, muscle, and fat, increase the amount of time that it takes for anesthesia to wear off.
What is the MAC?
alveolar concentration of an inhaled anesthetic that is needed to prevent movement in 50% of patients.
How do local anesthetics work?
bind sodium channels to prevent channel activation. this blocks sodium influx and prevents depolarization- you can't get an AP.
When is local anesthesia dangerous? Why/what happens?
when it gets to other parts of the body, like the heart and brain, where it can cause heart block, bradycardia, CV collapse, CNS depression, coma, and death at high doses.
What happens with low doses of local anesthesia poisoning?
anti-arrhythmic effects on heart
seizure in brain
4 stages of anesthesia?
I: sedation, amnesia, analgesia
2. loss of consiousness, excitement, instability, airway hyperactivity
3. surgical anesthesia
4. medullary suppresion, CV collapse, death
try not to spend time in stage 2 (or 4).
what is context senstive half time, and what does it highlight about the use of IV anesthetics?
context sensitive half time is the time it takes for the concentration of the a drug to fall to 1/2 of what it was in the central compartment (central compartment is the site of action- the brain) it DEPENDS ON THE AMOUNT OF INFUSION TIME.
reflects the fact that redistribution of the drug is the most important thing in terms of when it leaves the site of action- more important than metabolism or elimination.
What is the MOA for most anesthetics (barbiturates, benzodiazepines, propofol)?
interact with the GABAa receptor
increase the chance that GABA will bind its receptor
more bound GABA means more Cl ions
more Cl ions --> hyperpolarization of the neuron
inhibition of the AP.
ketamine is an exception
What is the effect of most anesthesia on the CV system?
pressure decrease, cardiac output decreased, vascular resistance decreased, venodilation increased. Ketamine is the opposite.
What is the effect of most anesthesia on respiration?
usually causes respiratory depression (ketamine is an exception; dexmedetomidine also doesn't seem to suppress ventilation).