Egar Video #8 Circulatory Effects of Inhaled Anesthetics

Question 1

Different anesthetics on the circulation are ______, particularly at the phase of _________

Answer 1

different anesthetics on the circulation are similar, particularly at the phase of maintenance

Question 2

Desflurane studies used toe temperature to assess

Answer 2

peripheral vasodilation –> digits have shunts to control heat

per chart: vasodilation occurs (increased to ~36C) at 2% Des

Question 3

At <0.3 MAC aka 2% Des, vasodilation occurs at __C

what is the clinical implication?

Answer 3

vasodilation occurs (increased to ~36C)

CI: patient is getting colder at 0.3 MAC aka 2% Des

Question 4

Anesthesia effect on temperature control range

Answer 4

the range broadens and is no longer tightly controlled

The deeper the anesthesia, the wider it broadens.

Question 5

Vasodilation can cause drop in ______ _______ which will subsequently ___ BP

clinical benefit?

Answer 5

vasodilation –> drop in peripheral resistance –> drop BP

buttttt we can start peripheral IVs

Question 6

Maintenance w/ potent inhaled agents:
_____ MAP
_____ HR at deeper levels
_____ SVR
_____ Cardiac Index

Answer 6

Decrease MAP
Increase HR
Decrease SVR
No Change to CI

Question 7

Potent Inhaled Agents Relationships:
Desflurane increase HR at ______ levels of anesthesia than ______
Halothane: ____ SVR, ____ CO

Answer 7

Desflurane increase HR at lighter levels of anesthesia than Sevoflurane.

Halothane: increases SVR, depresses CO

Question 8

Long duration of Inhaled Anesthetic:
Initial effects (2)
Later effects (2)

Answer 8

Initially: decrease in HR and greater decrease in BP
Later: HR and CO increase; eventually BP also increased

Question 9

Changing from controlled ventilation to spontaneous ventilation, what two things will influence hemodynamics?

Answer 9

1: Decreases in ventilation –> increase CO2
2: Negative pressure breathing will increase venous return

Question 10

Changing from controlled ventilation to spontaneous ventilation:
Can also expect CO to ___ & PVR to ____

Answer 10

CO will increase
PVR will decrease (CO2 vasodilates)

Question 11

Meaning of MAC_BAR

Greater for which anesthetic?

Answer 11

Blockade of Autonomic Reflexes in 50% of people

Greater Sevoflurane than Desflurane or Isoflurane

Question 12

Both Sevoflurane and Desflurane allowed a limited ____ ________ to stimulus.

Answer 12

Limited SNS Response

Question 13

Sevoflurane and Desflurane do not prevent?

Answer 13

do NOT prevent autonomic response to surgical stimulus
(Aka they are not perfect analgesics)

Question 14

What medication can be given to decrease MAC_BAR ?

Answer 14

Fentanyl will synergistically decrease MAC_BAR.

Question 15

MAC_IT

Answer 15

concentration at which there’s suppression of response to ETT.
well above traditional MAC

Question 16

Which volatile causes higher Arterial BP at 2 MAC?

Answer 16

Sevoflurane

Question 17

What airway condition improves 2 MAC better and why?

Answer 17

2 MAC better w/ spont ventilation because the anesthetic is more soluble.

Question 18

MAC 1 to 1.5 :
Desflurane Effect
Sevoflurane Effect

Answer 18

D: Cardiovascular stimulation
S: Cardiovascular depression

Question 19

Desflurane Relative insolubility leads to

Answer 19

leads to rapid equilibration in FA/FI

Question 20

What effect can be effected if you double Desflurane from 6% to 12% with no fentanyl premedication

Answer 20

• Rapid increase of FI
• BP and HR transiently increase
• in 10mins w/ no surgical stimulus -> return to baseline

Question 21

How to prevent desflurane cardiovascular effects?

Answer 21

premedicate the patient with opioids

Question 22

Describe Desflurane’s
First Step vs 2nd & Third Step

Answer 22

1st: Dramatic BP increase returns to control levels 6 minutes later
2&3: Absence of meaningly BP change.

Question 23

Trait of Desflurane Receptors

Answer 23

Receptors that mediate response rapidly adapt to higher concentration of desflurane.

Question 24

High doses of Sevoflurane can cause

Answer 24

Concern is profound bradycardia in children

Children require sustained heart rate to protect cardiac output

Question 25

Treatment for side effect of high Sevoflurane doses

Answer 25

Nothing Extra!
Just rapidly decreasing sevoflurane concentration

Question 26

Are there many Arrhythmogenic Inhaled Anesthetic?
Examples?

Answer 26

Halothane is the only Arrhythmogenic
Other anesthetics have zero concern.

Question 27

Describe Desflurane vs Sufentanil Ischemic Effect

Answer 27

• Desflurane: increase HR and heighten ischemia appearance.
• S: More ischemia during maintenance

Question 28

Is Desflurane cardioprotective?

Answer 28

Studies show cardioprotective

most protective volatile for infarct size.

Question 29

How do Potent Inhaled Anesthetics Protect Against Transient Myocardial Ischemia (4)

Answer 29

• enhance contractile recovery after MI
• Decrease infarct size from occlusion
• Protect against reperfusion injury
• Mimic ischemic preconditioning of the heart

Question 30

What is Coronary Steal

Answer 30

Vasodilation of normal healthy coronaries that shunt and diverts blood flow from stenotic areas receiving collateral flow.

Question 31

Inhaled Anesthetics tend to decrease ________ in all ______.

Answer 31

Tend to decrease resistance in all tissues.

Question 32

Anesthesia effect on Autoregulation

Answer 32

Anesthesia narrows range of Autoregulation
Anesthetic Drugs raise the entire autoregulation like up!