tony figaji mbchb, mmed, fcs, phd head of pediatric neurosurgery red cross children’s hospital...
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Tony Figaji MBChB, MMed, FCS, PhDHead of Pediatric NeurosurgeryRed Cross Children’s HospitalUniversity of Cape Town
•Neurocritical care is underdeveloped•Pediatric neurocritical care is even worse•Secondary brain injury is underappreciated
•The brain is complex•Children are physiologically different•Individual and temporal heterogeneity•Many different causes for raised ICP, standard Rx•Surrogate markers of brain health used•Direct measures of brain physiology?
Brain tissue oxygen tensionNear-infrared spectroscopyJugular venous saturationContinuous EEGMicrodialysisTCD / autoregulationContinuous CBFPhysiological imaging
1. Classic cellular oedema
2. Hyperemia
3. Vasospasm
4. Subclinical seizures
5. Impaired autoregulation
GCS 4ICP = 35
GCS 4ICP = 35
GCS 4ICP = 35
GCS 4ICP = 35
GCS 4ICP = 35
BrO2 lowCBF↓/N
BrO2 high, FV / CBF high
BrO2 low, FV high/ LR↑
BrO2 low, EEG typical
BrO2 passive,ARI low
Examined associations with outcome in multivariate model: clinical, physiological, radiological
Adjusted Odds Ratio for poor outcome:PbtO2<10 for >2 hoursOR 10.8 (1.4-82.4)PbtO2<5 for >1 hour OR 27.4 (1.9-391)
Strongest independent predictor of outcomeMortality for series = 9.6%
Low BrO2 is associated with poor outcome
Childs Nerv Syst. 2009 Oct;25(10):1325-3
It is not a surrogate marker of something else
It is not predicted by measures of initial injury severity
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< 20 mmHg < 15 mmHg < 10 mmHg < 5 mmHg
%ofpts
Brain hypoxia/ischemia is common despite observing current thresholds for treatment based on available evidence
Figaji et al, Neurosurgery. 2008 Jul;63(1):83-91
BrO2
decompressive craniectomy
Can evaluate the effects of intervention
Figaji et al, Acta Neurochir Suppl. 2008;102:77-80
ICP
PbtO2
MAP
ICM+
Increase in blood pressure
Pressure autoregulation, intracranial pressure and brain tissue oxygenation in children with severe traumatic brain injuryFigaji et al. J Neurosurg Peds, 2009;4:420-8
PbtO2 : 28.7 ± 6.8 mmHg
CPP : 64 ± 15 mmHg
FiO2 : 46 ± 12%
PbtO2 : 33.3 ± 11.8 mmHg
CPP : 70 ± 13 mmHg
FiO2 : 47 ± 13%
P=0.002
P=0.021
P= 0.474
Account for CPP change:
Co-efficient 0.3356, P=0.001
4 hour period post-RBCTBaseline values
The effect of blood transfusion on brain oxygenation in childrenwith severe traumatic brain injuryFigaji et al. Pediatric Crit Care Med 2009
Blood transfusion
34 patients, 291 TCD studies
Mean Flow Velocity (MCA):
95 (79-115) range 32-180cm/s
Figaji et al, Surgical Neurology 2009; 72:389-394
Patients are different
Yes
No
•Depends on correct application and interpretation•Intervention misapplied can have equally hazardous effects•The treatment may be worse than the problem
•Gives us more information•Lets us know when patients are getting into trouble before an established problem•Helps interpret the underlying pathophysiological problem•Helps us titrate therapy appropriately•Probably reduces secondary injury
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