Egar Video #8 Circulatory Effects of Inhaled Anesthetics Flashcards
Different anesthetics on the circulation are ______, particularly at the phase of _________
different anesthetics on the circulation are similar, particularly at the phase of maintenance
Desflurane studies used toe temperature to assess
peripheral vasodilation –> digits have shunts to control heat
per chart: vasodilation occurs (increased to ~36C) at 2% Des
At <0.3 MAC aka 2% Des, vasodilation occurs at __C
what is the clinical implication?
vasodilation occurs (increased to ~36C)
CI: patient is getting colder at 0.3 MAC aka 2% Des
Anesthesia effect on temperature control range
the range broadens and is no longer tightly controlled
The deeper the anesthesia, the wider it broadens.
Vasodilation can cause drop in ______ _______ which will subsequently ___ BP
clinical benefit?
vasodilation –> drop in peripheral resistance –> drop BP
buttttt we can start peripheral IVs
Maintenance w/ potent inhaled agents:
_____ MAP
_____ HR at deeper levels
_____ SVR
_____ Cardiac Index
Decrease MAP
Increase HR
Decrease SVR
No Change to CI
Potent Inhaled Agents Relationships:
Desflurane increase HR at ______ levels of anesthesia than ______
Halothane: ____ SVR, ____ CO
Desflurane increase HR at lighter levels of anesthesia than Sevoflurane.
Halothane: increases SVR, depresses CO
Long duration of Inhaled Anesthetic:
Initial effects (2)
Later effects (2)
Initially: decrease in HR and greater decrease in BP
Later: HR and CO increase; eventually BP also increased
Changing from controlled ventilation to spontaneous ventilation, what two things will influence hemodynamics?
1: Decreases in ventilation –> increase CO2
2: Negative pressure breathing will increase venous return
Changing from controlled ventilation to spontaneous ventilation:
Can also expect CO to ___ & PVR to ____
CO will increase
PVR will decrease (CO2 vasodilates)
Meaning of MACBAR
Greater for which anesthetic?
Blockade of Autonomic Reflexes in 50% of people
Greater Sevoflurane than Desflurane or Isoflurane
Both Sevoflurane and Desflurane allowed a limited ____ ________ to stimulus.
Limited SNS Response
Sevoflurane and Desflurane do not prevent?
do NOT prevent autonomic response to surgical stimulus
(Aka they are not perfect analgesics)
What medication can be given to decrease MACBAR ?
Fentanyl will synergistically decrease MACBAR.
MACIT
concentration at which there’s suppression of response to ETT.
well above traditional MAC
Which volatile causes higher Arterial BP at 2 MAC?
Sevoflurane
What airway condition improves 2 MAC better and why?
2 MAC better w/ spont ventilation because the anesthetic is more soluble.
MAC 1 to 1.5 :
Desflurane Effect
Sevoflurane Effect
D: Cardiovascular stimulation
S: Cardiovascular depression
Desflurane Relative insolubility leads to
leads to rapid equilibration in FA/FI
What effect can be effected if you double Desflurane from 6% to 12% with no fentanyl premedication
- Rapid increase of FI
- BP and HR transiently increase
- in 10mins w/ no surgical stimulus -> return to baseline
How to prevent desflurane cardiovascular effects?
premedicate the patient with opioids
Describe Desflurane’s
First Step vs 2nd & Third Step
1st: Dramatic BP increase returns to control levels 6 minutes later
2&3: Absence of meaningly BP change.
Trait of Desflurane Receptors
Receptors that mediate response rapidly adapt to higher concentration of desflurane.
High doses of Sevoflurane can cause
Concern is profound bradycardia in children
Children require sustained heart rate to protect cardiac output
