Regional changes in cerebral blood flow oxygenation can indicate global changes in cerebral blood flow during coronary artery occlusion in juvenile pigs

摘要

Near infrared spectroscopy (NIRS) is a widely employed method for assessment of regional cerebral oxygenation (R_c_StO_2). R_c_StO_2 values are expected to vary with changes in the relative amount of oxyhaemoglobin. The present experimental study aimed to assess the response of R_c_StO_2 to controlled alterations of carotid blood flow (CQ). Landrace pigs were anesthetized followed by surgical preparation. Cyclic variations in cardiac output were accomplished by intermittently occluding the main stem of the left coronary artery. A flow measurement probe for assessing CQ was placed around the left carotid artery. One NIRS probe was placed on the left ipsilateral forehead to assess regional cerebral oximetry. Simultaneous registration of CQ and R_c_StO_2 was conducted. There was a strong correlation for variation in CQ and R_c_StO_2 signal values. Based on coherence analysis the fraction of power of the R_c_StO_2 that was coherent with the CQ signal reached 0.84 ± 0.12 (P < 0.05) for frequencies lower than 0.1 Hz. The agreement of the sampleto- sample co-variation, as assessed by the Pearson correlation coefficient, was 0.83 ± 0.08 (P < 0.05). One explanatory component for variations in cerebral oxygenation verified by NIRS should be attributed to variations in the cerebral blood flow.