Usefulness of monitoring with near infrared spectroscopy during retrograde cerebral perfusion

: Recently retrograde cerebral perfusion (RCP), a newly developed technique for cerebral protection during surgical replacement for thoracic aortic aneurysm, has been used in many institutes. However, there is no established monitoring methods for cerebral oxygenation during this procedure. In the present study, we examined if near infrared spectroscopy (NIR) is useful for monitoring cerebral oxygenation during RCP. We studied 7 patients undergoing operations for aneurysms of the ascending aorta and transverse arch in the supine position (Group A) and another seven patients undergoing operations for aneurysms of the transverse arch and descending aorta in the lateral decubitus position (Group D) in this study and monitored cerebral oxygenation with NIR. NIR showed a slow but continuous decrease in oxygenated hemoglobin and an increase in deoxygenated hemoglobin during RCP, while these changes disappeared following the termination of RCP. The degree of these changes in Group D was significantly greater than that in Group A. In comparison, we observed rapid reduction of oxygenated hemoglobin during the period of circulatory arrest and low perfusion pressure with NIR, suggesting the usefulness of RCP for cerebral oxygenation. NIR may be a useful method of monitoring cerebral oxygenation during RCP.