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- Title
Precision of coherence analysis to detect cerebral autoregulation by near-infrared spectroscopy in preterm infants.
- Authors
Gitte Holst Hahn; Karl Bang Christensen; Terence S. Leung; Gorm Greisen
- Abstract
Coherence between spontaneous fluctuations in arterial blood pressure (ABP) and the cerebral near-infrared spectroscopy signal can detect cerebral autoregulation. Because reliable measurement depends on signals with high signal-to-noise ratio, we hypothesized that coherence is more precisely determined when fluctuations in ABP are large rather than small. Therefore, we investigated whether adjusting for variability in ABP (variabilityABP)improves precision. We examined the impact of variabilityABPwithin the power spectrum in each measurement and between repeated measurements in preterm infants. We also examined total monitoring time required to discriminate among infants with a simulation study. We studied 22 preterm infants (GA<30)yielding 215 10-minmeasurements. Surprisingly, adjusting for variabilityABPwithin the power spectrum did not improve the precision. However, adjusting for the variabilityABPamong repeated measurements (i.e., weighting measurements with high variabilityABPin favor of those with low) improved the precision. The evidence of drift in individual infants was weak. Minimum monitoring time needed to discriminate among infants was 1.3–3.7 h. Coherence analysis in low frequencies (0.04–0.1 Hz)had higher precision and statistically more power than in very low frequencies (0.003–0.04 Hz). In conclusion, a reliable detection of cerebral autoregulation takes hours and the precision is improved by adjusting for variabilityABPbetween repeated measurements.
- Subjects
NEAR infrared spectroscopy; COHERENCE (Optics); CEREBRAL arteries; BLOOD pressure; SIGNAL-to-noise ratio; PREMATURE infants; PATIENT monitoring
- Publication
Journal of Biomedical Optics, 2010, Vol 15, Issue 3, p037002
- ISSN
1083-3668
- Publication type
Article