1. 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

2. Masimo Inc.: Scientific Advisory Board

3. MY BIAS
I strongly believe that Propofol-TIVA is a superior anesthetic to Inhalational-Volatile Agent anesthesia in most instances.
My Bias

4. My Interpretation of the Scientific Literature
TIVA is associated with:
Less nausea
Better mood scores
Lower pain scores
Higher quality of recovery scores
TIVA is associated with:
Less nausea
Better mood scores
Lower pain scores
Higher quality of recovery scores

5. Confession
Doing TIVA well is more difficult that giving volatile anesthesia!

6. Reason #1: Population Variation
MAC
Cp50
2 SD = 0.3 MAC
2 SD = ~ 8 mcg ml-1

7. Reason #3: Synergy Differences10 8 6 4 2 12 14 20
MAC
1.0
0.5
1.5
Propofol Cp50
mcg ml-1
95%
95% 5% 5%
Fentanyl or Remifentanil
ng ml-1
Fentanyl or Remifentanil
ng ml-1

8. 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?

9. Propofol and Frontal EEG
Increasing Propofol

11. 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?

12. One Educational Goal of the UVM TIVA Rotation
Learn to titrate propofol to EEG and DSA parameters, not to a processed EEG index value.

13. EEG Guidance a al Goldilocks
JUST RIGHT
TOO DEEP
TOO LIGHT

14. TOO LIGHT
JUST RIGHT
TOO DEEP

15. JUST RIGHT

16. Just Right

17. TOO LIGHT
JUST RIGHT

18. Too Light

19. TOO DEEP

20. Too Deep

21. TOO LIGHT
JUST RIGHT
TOO DEEP

22. TOO LIGHT
JUST RIGHT
TOO DEEP

23. Becoming Too Deep

24. Too Deep Progression
Finally, just before burst supression, the remaining alpha power is overwhelmed by the delta power and the spectral edge is quite low.
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

25. Just Right > Too Deep > Just Right

26. Putting it Together Goal: “Sweet Spot” of Synergy
Remifentanil or Sufentanil x 10
ng ml-1
Propofol Cp50
mcg ml-1 10 8 6 4 2 12 14 20
95%
Propofol 2 mg kg-1, then mcg kg-1 min
Remifentanil 1 mcg kg-1, then mcg kg-1 min OR
Sufentanil 0.3 mcg kg-1 ,then mcg kg-1 hr-1
Titrate propofol infusion to EEG parameters with Goldiloxian logic.
Titrate opioids to the usual parameters.
Enjoy an excellent anesthetic! 5%

27. 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.

28. Illustrative Case Propofol 2 mg kg-1, then 125 mcg kg-1 min-1
Remifentanil or Sufentanil x 10
ng ml-1 10 8 6 4 2 12 14 20
95%
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
Required several 100 mg propofol boluses and increases in infusion rate for inadequate EEG “level”
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 5%

29. 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

30. 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 processed- EEG indices.