Bedside assessment of cerebral vasospasms after subarachnoid hemorrhage by near infrared time-resolved spectroscopy

We examined the usefulness of near infrared time-resolved spectroscopy (TRS) for detection of vasospasm in subarachnoid hemorrhage (SAH). We investigated seven aneurysmal SAH patients with poor clinical conditions (WFNS grade V) who underwent endovascular coil embolization. Employing TRS, we measured the oxygen saturation (SO(2)) and baseline hemoglobin concentrations in the cortices. Measurements of TRS and transcranial Doppler sonography (TCD) were performed repeatedly for 14 days after SAH. In four of the seven patients, the SO(2) and hemoglobin concentrations measured in the brain tissue of the middle cerebral artery territory remained stable after SAH. However, in three patients, TRS revealed abrupt decreases in SO(2) and total hemoglobin between 5 and 9 days after SAH. Cerebral angiography performed on the same day revealed severe vasospasms in these patients. Although TCD detected the vasospasm in two of three cases, it failed to do so in one case. TRS could detect vasospasms after SAH by evaluating the cortical blood oxygenation.