The Limitations of Near-Infrared Spectroscopy to Assess Cerebrovascular Reactivity

• DOI: 10.1213/ane.0b013e3182285dc0
• Publication Date: 2011-08-05T13:41:51Z
• Authors: Jennifer Diedler; Christian Zweifel; Karol P. Budohoski; Magdalena Kasprowicz; Enrico Sorrentino; Christina Haubrich; Kenneth M. Brady; Marek Czosnyka; John D. Pickard; Peter Smielewski
• Keywords: Cerebral autoregulation; Reactivity; Deoxygenated Hemoglobin

In Brief BACKGROUND: A total hemoglobin reactivity index (THx) derived from near-infrared spectroscopy (NIRS) has recently been introduced to assess cerebrovascular noninvasively. Analogously the pressure (PRx), THx is calculated as correlation coefficient with arterial blood (ABP). However, reliability of in injured brain uncertain. Although slow oscillations have described NIRS signals, their significance for assessment autoregulation remains unclear. current study, we investigated role NIRS-based monitoring. METHODS: This study was based on a retrospective analysis data that were consecutively recorded different project published previously. Thirty-seven patients traumatic injury and admitted Addenbrooke's Neurosciences Critical Care Unit between June 2008 2009 included. After artifact removal, performed spectral tissue (THI, measure oxy- deoxygenated hemoglobin) intracranial (ICP) signal. PRx moving correlations ICP ABP, THI respectively. The agreement function normalized power (0.015–0.055 Hz) contained input signals assessed performing between-subject within-subject analyses. Furthermore, values right left sides analyzed. RESULTS: depended signals. Between-subject comparisons revealed significant (r = 0.80, 95% confidence interval 0.53–0.92, P < 0.01) wave activity >0.4 signal, compared r 0.07 (95% −0.40 0.51, 0.79) remaining files. suggested may be used substitute only when there an at least moderate 0.36) sides. CONCLUSIONS: Our results suggest can noninvasive PRx, but during phases sufficient good measures both seems prerequisite comparison global (PRx) versus more local index. Nevertheless, desirable without monitoring help guide ABP management these patients. Published ahead print August 4, 2011