depth of anaesthesia monitoring after subarachnoid haemorrhage... comfortably numb? douglas duncan...
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depth of anaesthesia monitoring after subarachnoid haemorrhage...
comfortably numb?
douglas duncanwestern general hospitaledinburgh
will cover
1. why we thought it would be useful
2. which patients we looked at
3. what we did
4.how we analysed the results, PK, sensitivities.
5. summary.
how did this happen?Melbourne 2002
Royal Melbourne Hospital
B-Aware Trial
return to UK
1. The patient must not move under any circumstances. TIVA and paralysed (at WGH), access to patient limited.
2. Many of these patients are of decreased conscious level prior to any anaesthetic being given. Underdose/Overdose.
3. The degree of surgical stimulation is probably very low.
4. Catastrophic intracerebral events – cerebroprotection.
5. We DO NOT think awareness is an issue.
GDC (Guglielmi Detachable Coils ) Anaesthesia - issues
why did we think this would be useful
Microcatheter is placed through the parent blood vessel into the lumen of the anuerysm.
GDC microcoils are placed through the microcatheter into the aneurysm lumen.
The coil is detached (fuse) from the pusher wire which is then removed. Additional coils are then placed sequentially until the aneurysm will not accept any more coils
GDC Anaesthesia – patients
• SAH within days• Vasospasm – conscious
level
• +/- SAH• recovered/good neuro
function
2 patient groups
1. elective.
2. emergency.
Methods and Materials
•MREC and LREC approval.•Patients undergoing ‘coiling’ recruited.•All had recent subarachnoid haemorrhage.•Total 38 patients.
•Standard monitoring.•ECG, Pulse, IBP, SpO2.•Datex-Ohmeda S/5 Monitoring.
•Propofol, remifentanil, atracurium anaesthetic.
•Entropy and Bispectral index monitoring.•Entropy M Module, BIS XP•Indices recorded /5seconds •Laptop PC•Datex-Ohmeda S/5 Collect software•All drug dosing and changes to infusion recorded manually.
Patient Demographics
age distribution of included patients
0
10
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40
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60
70
80
0 5 10 15 20 25 30 35 40patient number
ag
e (
ye
ars
)
mean 53.7 yrs
male 12/38female 26/38
Average “bleed-coil” time = 4.95 days (min 1, max 22)Patient Demographics
0
5
10
15
20
25
30
nu
mb
er
of
pa
tie
nts
1 2 3 4 5
grade
WFNS grades
WFNS score1. GCS 15, No motor deficit or aphasia.
2. GCS 13-14, No motor deficit or aphasia.3. GCS 13-14, Any motor deficit or aphasia.
4. GCS 7-12, With or without deficit.5. GCS 3-6, With or without deficit
anaesthetist – blind to BIS/Entropy indices
why?
don’t know the numbers mean anything.
1.Presedation = 15secs data immediately prior to first sedative drug
2. LOC = 15 secs data, starting at no verbal response, no eyelash reflex
3. Intubation = 15 secs data starting 60 prior to ET tube passing through vocal cords
4. Stable = 15 secs data immediately prior to femoral catheter puncture
5. Eyelash return = 15 secs data after return of eyelash reflex only
6. Extubation = 15 secs data after patient extubated.
When did we take the data.......continuously but looking particularly at.....
= 6 clinically distinct depths
+ approx 75 hours data
Measuring the Performance of Anesthetic Depth Indicators.
Anesthesiology. 84(1):38-51, January 1996.
Smith, Warren D. PhD; Dutton, Robert C. MD; Smith, N. Ty MD
one of the properties of an ideal monitor includes;
1. Monotonicity – increasing clinically observed depth must always agree with increasing indicated depth.
PK describes this
PK
Measure of “degree of association”
is decreasing BIS/ENTROPY number associated with increasing clinical depth – ie is there concordance?
number between 0 and 1
1 indicates ideal concordance
0 indicates ideal discordance
0.5 equals a chance concordance.
original graphic Dutton, Smith, 1996
100 60 40 20 PK=1
100 100 70 100 PK 0.58
PK for deepening
PK for lightening
other points to note about PK
PK LOC
BIS 0.951
RE 0.862
SE 0.819
PK verbalBIS 0.89 – 0.91RE 0.83 – 0.88SE 0.81 – 0.86Vanluchene et alBJA Nov 2004
PK to eyelash regain
BIS 0.965
RE 0.913
SE 0.843
0
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20
30
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100
pre-sedation LOC intubation stablereturn eyelash
extubation
BIS
0
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100
pre-sedation LOC intubation stablereturn
eyelash extubation
RE
0
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BIS
SE
RE
pre sedation LOC
pK BIS = 1.000pK RE = 0.444pK SE = 0.056
pt6 =53yo femaleSAH<24hrsGCS 15, WFNS gd1p comm aneurysm
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BIS
SE
RE
loss of eyelash reflex intubation 60 secs prepre sedation
56 year maleSAH day 4GCS 15 WFNS gd1MCA aneurysm
pk transition 1BIS 1.000SE 1.000RE 1.000
pk transition 2BIS 1.000SE 0.000RE 0.000
pk overallBIS 1.000SE 0.667RE 0.667
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1003
00
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BIS
Bispectral Index behaviour @ eyelash return
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RE
Response Entropy behaviour @ eyelash return
0
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10030
0
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120 90 60 30 0 30 60 90 120
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BIS
RE
eyelash return
secs
sens
itivi
ty
1-specificity
ROC curves reminder(Receiver Operative Characteristics)
1.0
1.0
http://www.anaesthetist.com/mnm/stats/roc/
ROC for all patients
• test to detect presence of eyelash reflex.•all indices very good•high sensitivity•high specificity
AUC SE
BIS 0.993 0.000
RE 0.974 0.001
SE 0.962 0.002
AUC SE
BIS 0.987 0.001
RE 0.982 0.002
SE 0.967 0.003
AUC SE
BIS 0.970 0.003
RE 0.900 0.011
SE 0.880 0.012
grade1
grade 2
grade 3
cut off sensitivityspecificit
y
60 0.966 0.959
69 0.949 0.966
66 0.927 0.974
52 0.930 0.969
56 0.951 0.974
51 0.900 0.975
60 0.886 0.954
56 0.869 0.958
72 0.848 0.976
Bispectral Index
available circa 1996
recent FDA approval – to reduce awareness
19% increased sales per year for 5 years
Profit this year
Improved platform XP
UK use of depth monitoring set to increase
AUC
0.823
maximum sensitivity = 72.7%maximum specificity = 78.5%cut off point = 99.4%
Summary..
1. BIS/Entropy – can be used in patients after subarachnoid haemorrhage.
2. Grade 1 and grade 2 patients works well.
3. Grade 3 patients (rarer) possibly some fall off in performance.
In our study,
BIS performed better than Entropy indices.
But Entropy;
a. Still functions very well.
b. May give advanced warning of light anaesthesia.
acknowledgements;
Keith Kelly – consultant anaesthetist WGH.Peter Andrews – consultant anaesthetist WGH.
Neuro anaesthetists/radiologists – WGH.
Theatre/angio suite staff WGH.
Lee Dalgety – Datex-Ohmeda.
F Duncan.
x rays
position
A Comparison of Frontal and Occipital Bispectral IndexValues Obtained During Neurosurgical Procedures
Toshie Shiraishi, MD, Hiroyuki Uchino, MD, Takeshi Sagara, MD, and Nagao Ishii, MDDepartment of Anesthesiology, Tokyo Medical University Hachioji Medical Center, Tokyo, Japan
25 patients – for clipping unruptured cerebral aneurysmspropofol/fentanyl anaesthesiacorrelation r2 = 0.9682 between occipital and frontalbut maintained at 40-60, little data on how monitors behaved outwith this area
properties of ideal anaesthetic depth monitor
Indicates the stage during light anaesthesia preceding conscious awareness
Real time presentation of results.
Closely reflects changing concentrations of anaesthetic agents and monotonic.
Able to stage the depth of anaesthesia for all anaesthetics on a common scale.
Practical and cost effective.lots of buts however…
ideal anaesthetic depth monitor, showing interindividual variability, but maintains monotonicity
0
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BIS
SE
RE
pre sedation loss of eyelash reflex intubation 45 secs pre
56 year maleSAH day 2GCS 15 WFNS gd1
transition 1pk BIS 1.000pk SE 1.000pk RE 1.000
transition 2pk BIS 0.389pk SE 0.000pk RE 0.000
overallpk BIS 0.796pk SE 0.667pk RE 0.667
cut off sensitivity % specificity% AUC (SE) sens+spec
BIS 61 94.85 96.06 0.989(0.0) 191
RE 66 93.68 95.96 0.966(0.1) 190
SE 66 89.72 97.36 0.952(0.2) 187Vanluchene et al BJA 93(5): 645-54 (2004)
BIS 63-74 177-182
RE 79-85 170-180
SE 73-77 174-180
ROC data for BIS RE SE.To detect difference between “anaesthesia” and awake/eyelash reflex present.
ROC Curve
Diagonal segments are produced by ties.
1 - Specificity
1.00.75.50.250.00
Sens
itivity
1.00
.75
.50
.25
0.00
Source of the Curve
Reference Line
SE
RE
BIS
Grade 2 Subarachnoid Haemorrhage
AUC SE
BIS 0.987 0.001
RE 0.982 0.002
SE 0.967 0.003
ROC Curve
Diagonal segments are produced by ties.
1 - Specificity
1.00.75.50.250.00
Sens
itivity
1.00
.75
.50
.25
0.00
Source of the Curve
Reference Line
SE2
RE2
BIS2
Grade 3 Subarachnoid Haemorrhage
AUC SE
BIS 0.970 0.003
RE 0.900 0.011
SE 0.880 0.012