文摘
We evaluated cerebral blood oxygenation (CBO) changes after SAH employing quantitative time-resolved near infrared spectroscopy (TR-NIRS). We investigated 11 age-matched controls and 14 aneurysmal SAH patients. Employing TR-NIRS, we measured the cortical oxygen saturation (CoSO2) and baseline hemoglobin concentrations in the middle cerebral artery territory. Measurements of TR-NIRS and transcranial Doppler sonography (TCD) were performed repeatedly after SAH. In six patients, the CoSO2 and hemoglobin concentrations remained stable after SAH; DSA did not reveal vasospasm in these patients. In eight patients, however, CoSO2 and total hemoglobin decreased abruptly between five and nine days after SAH. DSA revealed diffuse vasospasms in six out of eight patients. The reduction of CoSO2 predicted occurrence of vasospasm at a cut of value of 3.9-6.4 % with 100 % of sensitivity and 85.7 % of specificity. TCD failed to detect the vasospasm in four cases, which TR-NIRS could detect. Finally, TR-NIRS performed on day 1 after SAH revealed significantly higher CoSO2 than that of controls; but there was no significant difference in total hemoglobin. TR-NIRS detected vasospasm by evaluating the CBO in the cortex, and may be more sensitive than TCD. The cerebral oxygen metabolism in SAH might be reduced by brain damage due to aneurysmal rupture.