Continuous time-domain analysis of cerebrovascular autoregulation using near-infrared spectroscopy. Export

@article{citeulike:2713520, abstract = {BACKGROUND AND PURPOSE: Assessment of autoregulation in the time domain is a promising monitoring method for actively optimizating cerebral perfusion pressure (CPP) in critically ill patients. The ability to detect loss of autoregulatory vasoreactivity to spontaneous fluctuations in CPP was tested with a new time-domain method that used near-infrared spectroscopic measurements of tissue oxyhemoglobin saturation in an infant animal model. METHODS: Piglets were made progressively hypotensive over 4 to 5 hours by inflation of a balloon catheter in the inferior vena cava, and the breakpoint of autoregulation was determined using laser-Doppler flowmetry. The cerebral oximetry index (COx) was determined as a moving linear correlation coefficient between CPP and INVOS cerebral oximeter waveforms during 300-second periods. A laser-Doppler derived time-domain analysis of spontaneous autoregulation with the same parameters (LDx) was also determined. RESULTS: An increase in the correlation coefficient between cerebral oximetry values and dynamic CPP fluctuations, indicative of a pressure-passive relationship, occurred when CPP was below the steady state autoregulatory breakpoint. This COx had 92\% sensitivity (73\% to 99\%) and 63\% specificity (48\% to 76\%) for detecting loss of autoregulation attributable to hypotension when COx was above a threshold of 0.36. The area under the receiver-operator characteristics curve for the COx was 0.89. COx correlated with LDx when values were sorted and averaged according to the CPP at which they were obtained (r=0.67). CONCLUSIONS: The COx is sensitive for loss of autoregulation attributable to hypotension and is a promising monitoring tool for determining optimal CPP for patients with acute brain injury.}, author = {Brady, K. M. and Lee, J. K. and Kibler, K. K. and Smielewski, P. and Czosnyka, M. and Easley, R. B. and Koehler, R. C. and Shaffner, D. H.}, citeulike-article-id = {2713520}, citeulike-linkout-0 = {http://dx.doi.org/10.1161/STROKEAHA.107.485706}, citeulike-linkout-1 = {http://stroke.ahajournals.org/cgi/content/abstract/38/10/2818}, citeulike-linkout-2 = {http://view.ncbi.nlm.nih.gov/pubmed/17761921}, citeulike-linkout-3 = {http://www.hubmed.org/display.cgi?uids=17761921}, day = {1}, doi = {10.1161/STROKEAHA.107.485706}, issn = {1524-4628}, journal = {Stroke; a journal of cerebral circulation}, keywords = {autoregulation, doppler, index, nirs}, month = {October}, number = {10}, pages = {2818--2825}, posted-at = {2009-07-07 16:45:59}, priority = {3}, title = {Continuous time-domain analysis of cerebrovascular autoregulation using near-infrared spectroscopy.}, url = {http://dx.doi.org/10.1161/STROKEAHA.107.485706}, volume = {38}, year = {2007} }

TY - JOUR ID - citeulike:2713520 L3 - citeulike-article-id:2713520 N2 - BACKGROUND AND PURPOSE: Assessment of autoregulation in the time domain is a promising monitoring method for actively optimizating cerebral perfusion pressure (CPP) in critically ill patients. The ability to detect loss of autoregulatory vasoreactivity to spontaneous fluctuations in CPP was tested with a new time-domain method that used near-infrared spectroscopic measurements of tissue oxyhemoglobin saturation in an infant animal model. METHODS: Piglets were made progressively hypotensive over 4 to 5 hours by inflation of a balloon catheter in the inferior vena cava, and the breakpoint of autoregulation was determined using laser-Doppler flowmetry. The cerebral oximetry index (COx) was determined as a moving linear correlation coefficient between CPP and INVOS cerebral oximeter waveforms during 300-second periods. A laser-Doppler derived time-domain analysis of spontaneous autoregulation with the same parameters (LDx) was also determined. RESULTS: An increase in the correlation coefficient between cerebral oximetry values and dynamic CPP fluctuations, indicative of a pressure-passive relationship, occurred when CPP was below the steady state autoregulatory breakpoint. This COx had 92% sensitivity (73% to 99%) and 63% specificity (48% to 76%) for detecting loss of autoregulation attributable to hypotension when COx was above a threshold of 0.36. The area under the receiver-operator characteristics curve for the COx was 0.89. COx correlated with LDx when values were sorted and averaged according to the CPP at which they were obtained (r=0.67). CONCLUSIONS: The COx is sensitive for loss of autoregulation attributable to hypotension and is a promising monitoring tool for determining optimal CPP for patients with acute brain injury. IS - 10 JF - Stroke; a journal of cerebral circulation SN - 1524-4628 EP - 2825 TI - Continuous time-domain analysis of cerebrovascular autoregulation using near-infrared spectroscopy. VL - 38 SP - 2818 KW - autoregulation KW - doppler KW - index KW - nirs AU - Brady, KM AU - Lee, JK AU - Kibler, KK AU - Smielewski, P AU - Czosnyka, M AU - Easley, RB AU - Koehler, RC AU - Shaffner, DH PY - 2007/10/01/ UR - http://dx.doi.org/10.1161/STROKEAHA.107.485706 ER -