cerebral tissue oxygenation can be used instead of cerebral intravascular oxygenation to study...
TRANSCRIPT
Cerebral Tissue Oxygenation Can Be Used Instead of Cerebral Intravascular Oxygenation to Study Cerebral Autoregulation in
Prematurely Born Infants
Ir. D. De Smet*, Lic. J. Vanderhaegen**, Prof. Dr. G. Naulaers**
and Prof. Dr. Ir. S. Van Huffel*
KATHOLIEKE UNIVERSITEIT LEUVEN, BELGIUM
*DEPARTMENT OF ELECTRICAL ENGINEERING (ESAT-SCD)
**NEONATAL INTENSIVE CARE UNIT, UNIVERSITY HOSPITALS LEUVEN
Introduction
Problem : impaired cerebral autoregulationSolution : detect ΔHbD concordant with ΔMABP (with ΔSaO2=0)1
But …Problem : HbD (=HbO2-HbR) is not an
absolute valueSolution : prove that TOI may replace HbD
for measurement of impaired cerebral autoregulation
Acronyms :• MABP : mean arterial blood pressure• HbD : cerebral intravasc. oxygenation.• SaO2 : arterial oxygen saturation• TOI : cerebral tissue oxygenation_____________________________________________________[1] Tsuji et al., Pediatrics, 2000.
1. Introduction
2. Datasets
3. Methods
1. DC meth.
2. CPRT
3. Similarity meas.
4. Exp. results
5. Conclusion
Datasets
• 20 premature infants with need for intensive care
• MABP, SaO2, HbD and TOI measured simultaneously in the first days of life at University Hospitals Leuven
• HbD and TOI measured by NIRS (with NIRO300, Hamamatsu)
• Post menstrual age of 28.7 weeks (24-39)
• Weight : from 570 to 1470g
• Recording time : from 1h30 to 23h35
1. Introduction
2. Datasets
3. Methods
1. DC meth.
2. CPRT
3. Similarity meas.
4. Exp. results
5. Conclusion
Methods > DC methods
1. Introduction
2. Datasets
3. Methods
1. DC meth.
2. CPRT
3. Similarity meas.
4. Exp. results
5. Conclusion
• Correlation and (partial1) coherence coefficients to look at the direct concordance between signals MABP/HbD and MABP/TOI
• Frequency band of interest2 : 0 - 0.01Hz
• Sliding window approach3 : DC scores computed over 30-min epochs2
• SaO2 made constant4
______________________________________________________[1] Leuridan et al, ASME design eng div conf and exhibit on mech
vibration and noise, 1985. [2] Tsuji et al., Pediatrics, 2000.[3] Morren et al, Proc.23rd Annual Intern Conf IEEE Engineering in
Med and Biol Society, 2001. [4] De Smet et al, Proc. of the Belg. Day on Biomed. Eng. -
IEEE/EMBS Benelux Symp, 2006
Methods > CPRT
Problem : the DC score value differs from one time instant to another one : not handy to use
Solution : a measure that synthesizes the level of autoregulation of a patient for the whole recording time1,2 : the critical percentage of the recording time (CPRT)
____________________________________________________[1] Tsuji et al., Pediatrics, 2000.[2] Soul et al, Pediatric Research, 2007
1. Introduction
2. Datasets
3. Methods
1. DC meth.
2. CPRT
3. Similarity meas.
4. Exp. results
5. Conclusion
Methods > Similarity meas.
Aim : to prove that a signal may be replaced by another more handy one.
Particularly …
Question : may HbD (relative) be replaced by TOI (absolute) ?
Solution : derivation of similarity measures from the DC scores
Acronyms :DC score : direct concordance scoreHbD : cerebral intravasc. oxygenation.TOI : cerebral tissue oxygenation
1. Introduction
2. Datasets
3. Methods
1. DC meth.
2. CPRT
3. Similarity meas.
4. Exp. results
5. Conclusion
Experimental results
mCBS CB-CPRT
Mean of |r|
MSE
COH 0.76 0.81 0.027 0.0013
COR 0.63 0.71 0.043 0.0031
PCOH 0.70 0.78 0.041 0.0038
1. Introduction
2. Datasets
3. Methods
1. DC meth.
2. CPRT
3. Similarity meas.
4. Exp. results
5. Conclusion
Acronyms :• mCBS : mean correlation between DC score curves• CPRT : crit. percentage of the rec. time• CB-CPRT : correlation between CPRT curves• r : residual• MSE : mean square error
Conclusion
• Definition of a new synthesized measure of cerebral autoregulation : the CPRT
• Derivation of similarity measures proving that TOI can be used to assess impaired cerebral autoregulation in neonates
1. Introduction
2. Datasets
3. Methods
1. DC meth.
2. CPRT
3. Similarity meas.
4. Exp. results
5. Conclusion
Conference• Org. Committees• Fin. ContributorsGeneral Electric Company
Linde Gas
Philips Medical Systems
Gothia Medical AB
Bayer Schering Pharma
Unisense A/S
Kodak Carestream Health Sciences
Siemens Medical
Uppsala Kommun
Uppsala University
PhD grant• Fin. ContributorsResearch Council KULeuven
Flemish Government
Belgian Federal Science Policy Office
EU
ESA
• WorkgroupProf. Dr. Ir. S. Van Huffel
Prof Dr. G. Naulaers
Lic. J. Vanderhaegen
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