Pharmacology

Question 1

volatile agents - arrhythmias

Answer 1

sevo > des = iso

Question 2

volatile agents - coronary steal

Answer 2

• dilates healthy coronary vessels which takes blood away from the diseased vessels which were already dilated
• iso

Question 3

volatile agents - systemic vasculature

Answer 3

-reduces resistance by activating endothelial nitrous oxide synthase which releases nitrous oxide

Question 4

volatile agents - pulmonary blood flow

Answer 4

• NO and des increase pulmonary vasculature resistance

- iso inhibits hypoxic pulmonary vasoconstriction

Question 5

desflurane - rule of 24

Answer 5

-take des % times flow

>24 = sympathetic response and tachycardia
<24 = hypotension

Question 6

volatile agents - avoid in cardiac surgery

Answer 6

• des

- NO

Question 7

volatile agents - baroreceptor reflex

Answer 7

-suppresses at all parts (afferent, control center, efferent)

Question 8

volatile agents - anesthetic pre-conditioning

Answer 8

• protective mechanism to reduce the size of infarcts
• acts indirectly
• two times: 1-3 hrs, 2-3 days

Question 9

volatile agents - cardiac effects

Answer 9

• dose-dependent cardiac depression which is amplified in diseased tissue
• suppress L-type Ca channels in sarcoplasmic reticulum which prolongs isovolumetric relaxation and decreases contractility
• maintain CO, effects due to reduction in SVR

Question 10

intravenous agents - preconditioning

Answer 10

• do not offer benefits

- ketamine may block the body’s innate response

Question 11

Propofol

Answer 11

• negative inotrope: blocks L-type Ca channels
• antioxidant
• affects are more pronounced in patients with high sympathetic tone (shock, CHF)

Question 12

Midazolam

Answer 12

• 0.05-0.2 mg/kg

- does not provide analgesia, need to combine with Fentanyl or Ketamine

Question 13

Etomidate

Answer 13

• cardiostatic

- may see changes in patient’s with valvular heart disease

Question 14

Ketamine

Answer 14

-dual affect in myocardium: positive inotrope and impairs sarcoplasmic reticulum function

Question 15

Dexmedetomidine

Answer 15

-bolus can produce profound hypotension: give over 10 minutes

Question 16

opioid receptors

Answer 16

• mu, delta, kappa
• inhibit G-coupled protein receptors, closing N-type, voltage-gated Ca channels and open CA dependent inwardly rectifying K channels resulting in hyperpolarization

Question 17

opioid - cardiac affects

Answer 17

• reduce sympathetic outflow
• bradycardia (except Demerol which produces tachycardia)
• promotes ischemic preconditioning
• negative inotropic (need high doses, so clinically irrelevant)

Question 18

drugs for ischemia - do what? newer drugs do what?

Answer 18

• alter oxygen demand or oxygen supply

- new drugs increase the efficiency of oxygen utilization

Question 19

NO - how is it made

Answer 19

-breaking down arginine by the enzyme nitric oxide synthase (NOS) into citrulline and NO

Question 20

NO - where is it stored

Answer 20

-NO is not stored, has to be made when it is needed

Question 21

NO - effects; low and high

Answer 21

• low doses: venous dilation that reaches a ceiling

- high doses: arterial dilation, preferentially dilates coronary arteries

Question 22

NO donors - mechanism of action

Answer 22

-requires sulfhydryl groups that can become depleted leading to tolerance, giving the patient N-acetylcysteine (Mucinex) stops the deficiency

Question 23

NTG - drug interactions

Answer 23

• causes resistance to heparin

- avoid phosphodiesterase 5 inhibits

Question 24

NO - mechanism of action

Answer 24

• guanylyl cyclase
• GTP
• cyclic-GMP
• cGMP-dependent protein kinase
• lowers Ca
• smooth muscle relaxation