| Title: | Bedside Evaluation of Cerebral Autoregulation Using Frequency Domain Near Infrared Spectroscopy |
| Authors: | Mateo Calderon-Arnulphi, MD; Ali M. Alaraj, MD; Rodolfo G. Gatto, MD; Hrachya Nersesyan, MD; William Mantulin, MD; Antonios Michalos, MD; Enrico Gratton , PhD; Fady T. Charbel, MD |
| Abstract: | Strokes, hemorrhages and impaired cerebral blood flow are a frequent cause of morbidity and mortality in the United States. In these pathological conditions equilibrium of cerebral blood flow autoregulation is lost. Currently, there is no non-invasive portable tool to screen patients with possible impaired autoregulation.
We have used frequency domain near infrared spectroscopy (FD-NIRS) to monitor of 19 neurosurgical patients. FD-NIRS provides quantitative, non-invasive, continuous real time information about the brain oxygenation. Oxy- (HbO2), Deoxy- (HHb), total (tHb) hemoglobin concentrations and brain tissue oxygen saturation (SO2) are measured quantitatively. Eleven patients had superficial temporal artery to middle cerebral artery (STA-MCA) bypass for cerebral blood flow augmentation, 2 patients had carotid endartectrectomy and 6 patients had subarachnoid hemorrhages. All STA-MCA bypasses had SPECT scan showing impaired autoregulation on the affected side. FD-NIRS sensors were applied bilaterally on the scalp of patients on the affected and the contralateral side measuring cerebral oxygenation preoperatively in the supine and in the sitting position (fig1).
We simultaneously correlate changes in total-Hb concentration with changes in mean arterial blood pressure (MAP) during the head up tilting test. A normal autoregulation showed a negative inverse relationship between the MAP and the cerebral blood volume (CBV). Impaired autoregulation showed a positive linear relationship of MAP and CBV possibly because of maximum vasodilatation. All results of FD-NIRS studies did correlate with SPECT finding. 5 patients had follow up FD-NIRS studies one week later that showed correction of autoregulation to normal.
FD-NIRS provides a non-invasive and sensitive technique to evaluate patients with impaired autoregulation preoperatively and postoperatively. |
| Corresponding Author: | Mateo Calderon-Arnulphi, MD |
| Format: | Digital Poster (View) |
| Meeting: | CNS 2005 Boston, Massassuchets |