IV Anesthetics

Question 1

Name some barbiturates.

Answer 1

thiopental, methohexital, thiamylal

Question 2

What properties does thiopental provide?

Answer 2

anticonvulsant and amnestic properties, but POOR analgesic—-> in small doses may be hyperalgesic

Question 3

What negative properties does thiopental have?

Answer 3

depresses respiratory system, depresses myocardial contractility (decreasing SV, CO, and BP with reflexive increase in HR)

Question 4

What effect does thiopental have on cerebral blood flow?

Answer 4

increases cerebral vascular resistance—> decreasing cerebral blood flow and ICP

Question 5

What condition may increase the patients response to thiopental?

Answer 5

hypoproteinemia (hypoalbuminemia); thiopental is largely protein bound in plasma

Question 6

What are two types of patient conditions in which you should avoid the use of thiopental?

Answer 6

1) asthmatic–> due to possible histamine release

2) porphyria–> disease caused by inadequate porphyrin metabolism (contributes to heme precursors)

Question 7

What is the half-time of propofol?

Answer 7

0.5-1.5 hours (more rapid and complete awakening than other IV anesthetics)

Question 8

What are some positive and negative characteristics of propofol?

Answer 8

\+= more rapid and complete awakening, good antiemetic d\t it's action on the chemoreceptor trigger zone in the brainstem and vomiting center, anticonvulsant properties
-= depressed CO and SVR, HR is often unchanged, profound ventilatory depressant in comparison to thiopental, no analgesic properties

Question 9

What effect does propofol have on cerebral blood flow?

Answer 9

decreases CBF and CMRO2

Question 10

How do benzodiazepines work?

Answer 10

by enhancing the action of GABA (the brain’s major inhibitory neurotransmitter)

Question 11

Name 3 short acting benzos.

Answer 11

diazepam, lorazepam, midazolam

Question 12

What effect on the heart do benzos have?

Answer 12

minimal–> unless patient is volume depleted, in which profound hypotension can occur

Question 13

What are some of the CNS actions of benzos?

Answer 13

antianxiety, amnestic, sedative, hypnotic, and anticonvulsant; muscle relaxation is also produced; POOR analgesics

Question 14

What effect do benzos have on cerebral blood flow?

Answer 14

cause cerebral vasoconstriction–> lowering CBF and ICP

Question 15

Why can pain occur with administration of diazepam?

Answer 15

poorly H2O soluble, it is dissolved in an organic solvent

Question 16

Diazepam is _____% protein bound.

Answer 16

98-99%

Question 17

Ketamine produces ________ anesthesia.

Answer 17

dissociative

Question 18

Ketamine produces amnesia and profound analgesia by interacting with the _______ receptor.

Answer 18

NMDA-type glutamate

Question 19

Name some of the effects of Ketamine.

Answer 19

cerebral vascular dilator (CBF and ICP INCREASE), increases CMRO2, causes hypertonus and nystagmus, stimulates SNS (increases HR, CO, and BP)

Question 20

What type of patients are ideal candidates for Ketamine?

Answer 20

poor risk patients (trauma, elderly)

Question 21

Name 3 types of patients to AVOID Ketamine usage.

Answer 21

1) cardiac patients (ex-CAD)–> stress em dead
2) glaucoma patients (IOP increased)
3) patients with elevated ICP

Question 22

How is emergence of a patient that received ketamine?

Answer 22

Oh Joy–> dreams, hallucinations, n/v

Question 23

Is Ketamine a weak acid or base?

Answer 23

weak base with a pKa of 3.5-5.0–> do not mix with alkaline solutions to avoid precipitate

Question 24

What are some side effects of synthetic opioids?

Answer 24

profound respiratory depressant, promotes cardiac stability (slight bradycardia may occur), excellent analgesia, promotes n/v due to stimulation of chemoreceptor trigger zone, acts centrally to stimulate vagal nerve thus promoting bradycardia, truncal rigidity, promote cerebral vasoconstriction and decreased CBF and decreased ICP so long as ventilation is controlled–> if not build up of CO2 dilates cerebral vasculature

Question 25

What effect do opioids have on the biliary tract?

Answer 25

cause the sphincter of Oddi to spasm (controls release of digestive juices into the second part of the duodenum)–> pressure in the biliary tract increases
Tx= glucagon 1-2mg IM–> relaxes the sphincter

Question 26

What is an effect specific to morphine that can decrease SVR and BP? What types of patients should this be avoided in?

Answer 26

morphine; asthmatics

Question 27

What is the “safest” IV anesthetic to use for cardiovascular instability?

Answer 27

Etomidate

Question 28

What is a s\e that is specific to Etomidate in comparison to other IV anesthetics?

Answer 28

directly depresses cortisol output from the adrenal cortex; depresses immune system

Question 29

The CNS effects after bolus injection of an IV anesthetic are terminated primarily by _________.

Answer 29

redistribution