Anesthesia and PD

Question 1

What are the four cardinal signs/symptoms of Parkinson’s Disease?

Answer 1

1. Tremor (gets better with a directed movement)
2. Rigidity
3. Bradykinesia
4. Postural Instability

Question 2

What does rigidity indicate?

Answer 2

Pathology in the contralateral basal ganglia

Question 3

What is the most common way to differentiate between PD and atypical parkinsonism?

Answer 3

give L-DOPA and look for patient improvement

Question 4

Why do we adminsiter carbidopa with Levo-DOPA during PD therapy?

Answer 4

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

Question 5

Other than L-DOPA and dopamine receptor agonists, what kinds of drugs can we use to treat Parkinson’s disease?

Answer 5

MAO inhibitors to prevent dopamine degradation- selegiline and resagiline
or COMP inhibitor (just 1)

Question 6

What should I be cautious about in terms of barbituate administration?

Answer 6

contraindicated in patients with acute intermitant porphyria

Question 7

What should I be careful about with propofol?

Answer 7

supports bacterial growth and can cause sepsis
potential allergy issues (maybe)
not terribly forgiving

Question 8

What is one advantage of propofol?

Answer 8

low context-sensitive half time

Question 9

What should I be careful about with ketamine?

Answer 9

psychiatric effects
abuse
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)

Question 10

What is the only anesthetic that mimics sleep?

Answer 10

dexmedetomidine

Question 11

What is one of the most important and underappreciated goals of anesthesia?

Answer 11

reduce surgical stress response: long-term implications

Question 12

Where does anesthesia act?

Answer 12

brain AND spinal cord

spinal cord may be especially important for restricting movement.

Question 13

What is the myer-overton hypothesis and what are the problems with it?

Answer 13

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

Question 14

What are three advantages of inhalational anesthesia?

Answer 14

easy to administer
easy to eliminate
little metabolism to toxic substances

Question 15

What determines brain concentration of an inhaled anesthesia? What factors determine the speed with which a patient is roused following inhalational anesthesia?

Answer 15

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.

Question 16

What is the MAC?

Answer 16

alveolar concentration of an inhaled anesthetic that is needed to prevent movement in 50% of patients.

Question 17

How do local anesthetics work?

Answer 17

bind sodium channels to prevent channel activation. this blocks sodium influx and prevents depolarization- you can’t get an AP.

Question 18

When is local anesthesia dangerous? Why/what happens?

Answer 18

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.

Question 19

What happens with low doses of local anesthesia poisoning?

Answer 19

anti-arrhythmic effects on heart

seizure in brain

Question 20

4 stages of anesthesia?

Answer 20

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).

Question 21

what is context senstive half time, and what does it highlight about the use of IV anesthetics?

Answer 21

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.

Question 22

What is the MOA for most anesthetics (barbiturates, benzodiazepines, propofol)?

Answer 22

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

Question 23

What is the effect of most anesthesia on the CV system?

Answer 23

pressure decrease, cardiac output decreased, vascular resistance decreased, venodilation increased. Ketamine is the opposite.

Question 24

What is the effect of most anesthesia on respiration?

Answer 24

usually causes respiratory depression (ketamine is an exception; dexmedetomidine also doesn’t seem to suppress ventilation).

Question 25

What is the effect of most anesthesia on the CNS?

Answer 25

decrease in cerebral blood flow; decrease in perfusion pressure, decreases in the metabolic requirement for oxygen, decrease in intracranial pressure.
ketamine is the exception: Achilles heel of this medication.