IARS 2017 Annual Meeting and International Science Symposium
Improving Health Through Discovery and Education
May 6-9, 2017 • Washington, DC
Using EEG to Teach
Delivery of TIVA
Donald M Mathews, MD
Professor of Anesthesiology
Director of Research
Department of Anesthesiology
Robert Larner MD College of Medicine,
University of Vermont
IARS 2017 Annual Meeting and International Science Symposium
Improving Health Through Discovery and Education
May 6-9, 2017 • Washington, DC
• Masimo Inc.: Scientific Advisory Board
MY BIAS
I stronglyMy
believe
Bias that Propofol-TIVA is a superior
anesthetic to Inhalational-Volatile Agent anesthesia
in most instances.
My Interpretation of
the Scientific
Literature
TIVA
is associated with:
• •TIVA
is associated
with:
• Less nausea
• •Less
nauseamood scores
Better
• Better mood
•scores
Lower pain scores
• •Lower
pain quality of
Higher
scores
recovery scores
• Higher quality of
recovery scores
Confession
• Doing TIVA well is
more difficult that
giving volatile
anesthesia!
Reason #1: Population Variation
MAC
2 SD = 0.3 MAC
Cp50
2 SD = ~ 8 mcg ml-1
Reason #3: Synergy Differences
20
14
12
10
1.5
MAC 1.0
0.5
Propofol Cp50 8
mcg ml-1 6
4
95%
5%
1 2 3 4 5 6 7 8 9 10
Fentanyl or Remifentanil
ng ml-1
95%
2
5%
1 2 3 4 5 6 7 8 9 10
Fentanyl or Remifentanil
ng ml-1
We care for patients, not populations
• Wouldn’t it be nice if there
was a way to determine an
individual patient’s
requirement…
• That was more useful than
interpreting changes in the
sympathetic nervous system?
Increasing Propofol
Propofol and Frontal EEG
Brown and Purdon: Challenging
Dogma
• Can Anesthesiologists learn
to interpret EEG to make
clinical decisions?
• Can additional tools help
with this?
• Can we correlate EEG
changes with neurobiologic
circuitry?
One Educational Goal of the UVM TIVA
Rotation
• Learn to titrate propofol to EEG and DSA parameters,
not to a processed EEG index value.
EEG Guidance a al Goldilocks
JUST RIGHT
TOO DEEP
TOO LIGHT
TOO LIGHT
JUST RIGHT
TOO DEEP
JUST RIGHT
Just Right
TOO LIGHT
JUST RIGHT
Too Light
TOO DEEP
Too Deep
TOO LIGHT
JUST RIGHT
TOO DEEP
TOO LIGHT
JUST RIGHT
TOO DEEP
Becoming Too Deep
Too Deep Progression
Note: when “just right,
the Spectral edge is 2-3
Hz greater than the
alpha prominence
As things begin to be “too
deep”, the spectral edge
collapses into the alpha
prominence
Finally, just before burst
supression, the remaining
alpha power is overwhelmed
by the delta power and the
spectral edge is quite low.
Just Right > Too Deep > Just Right
Putting it Together
Goal: “Sweet Spot” of Synergy
20
• Propofol 2 mg kg-1, then 125150 mcg kg-1 min
• Remifentanil 1 mcg kg-1, then
0.085-0.1 mcg kg-1 min
OR
• Sufentanil 0.3 mcg kg-1 ,then
0.2-0.3 mcg kg-1 hr-1
• Titrate propofol infusion to
EEG parameters with
Goldiloxian logic.
• Titrate opioids to the usual
parameters.
• Enjoy an excellent
anesthetic!
14
12
10
Propofol Cp50 8
mcg ml-1 6
4
2
95%
5%
1 2 3 4 5 6 7 8 9 10
Remifentanil or Sufentanil x 10
ng ml-1
Illustrative Case: Patient 1:1000 (1:10,000 ?)
• 62 year old man, 175 cm, 81 kg
• Scheduled for multilevel lumbar decompression with hardware
placement
• Rx: metoprolol for HTN
• No issues with prior GA
• No Ethanol, drug use/abuse.
Illustrative Case
20
• Propofol 2 mg kg-1, then 125 mcg
kg-1 min-1
• Sufentanil 0.3 mcg kg-1 ,then 0.3
mcg kg-1 hr-1
14
12
10
• Required several 100 mg propofol
boluses and increases in infusion
rate for inadequate EEG “level”
6
• 250 mcg kg-1 min-1
• Required several 10 mcg sufentanil
boluses and infusion rate increases
for hemodynamic reasons.
• 0.6 mcg kg-1 hr-1
8
4
2
95%
5%
1 2 3 4 5 6 7 8 9 10
Remifentanil or Sufentanil x 10
ng ml-1
100 mg propofol,
increased to 250 mcg
kg-1 min-1 from 225
10 min from end:
Sufentanil discontinued.
Propofol 125 mcg kg-1 min-1
End of case:
Patient flipped over
Propofol discontinued
Opened eyes 3 minutes later
No coughing, bucking
Alert, oriented, comfortable
Conclusions
•Propofol TIVA can be difficult to delivery
accurately.
•Propofol causes predictable changes in
frontal EEG
•Practitioners can learn to titrate anesthetics
to the EEG and DSA.
•Ideally, the next generation of
anesthesiologists will not need processedEEG indices.