New Methods for Monitoring Cerebral Oxygenation and Hemodynamics in Patients with Subarachnoid Hemorrhage

Abstract

SummaryRadiographic cerebral vasospasm (CVS) after subarachnoid hemorrhage (SAH) do not reflect cerebral hemodynamics and oxygenation and may occur in the absence of clinical deficit and viceversa. This report is to describe preliminary findings in further development of a non invasive method to estimate regional cerebral oxygenation and perfusion. Measurements were performed with a technique combining near infrared spectroscopy (NIRS) and indocyaningreen (lCG) dye dilution. Successful data analysis has been performed based on the decomposition in pulsatile and non-pulsatile components of NIRS absorption data collected before and during the passage of ICG through the vascular bed under the NIRSdetector. First measurements in patients with CVS suggest that the technique could become a powerful tool in the detection and treatment of CVS. This non invasive technique can be done at the bedside, it seems to be safe, easy to perform and less time-consuming compared to conventional techniques.The influence of extracerebral bone and surface tissue on cerebral NIRS signal has not been clarified yet. Therefore a new subdural NIRS probe has been developed, which gives the opportunity to measure directly the concentration of the chromophores in the brain without the influence of extracerebral contamination. In future comparative measurements with conventional NIRS probes on the scalp will allow to quantify and eliminate extracerebral contamination from the NIRS signal.

Diffuse optics for tissue monitoring and tomography

“…Amongst many potential applications, NIRS/DOS has been utilized for cerebral monitoring of adults with traumatic brain injury (TBI) and subarachnoid hemorrhage (SAH) [440–445], ischemic stroke [80, 277–280, 446–453], sleep apnea and other sleep disorders [454–457], intraoperative brain monitoring [458, 459] and in neonates and children [433, 460–462]. This list is not exhaustive; it is meant to give a “flavor” of the field.…”

Near-infrared spectroscopy extended with indocyanine green dye dilution for cerebral blood flow measurement: Median values in healthy volunteers

“…An advantage of ICG is the presence of an absorption maximum near the isobestic point at a wavelength of 805 nm, where oxy-Hb and deoxy-Hb show the same absorption characteristics. ICG binds to plasma proteins, has a low toxicity, and is rapidly excreted by the liver, almost exclusively into the bile [9,13,14].…”

Lighting Up Neurovascular Surgery

“…To measure cerebral oxygenation and perfusion in patients, Keller and colleagues used a technique combining near infrared spectroscopy and ICG dilution. They analyzed the cases based on the decomposition in pulsatile and non-pulsatile components of the absorption data before and during the flow of ICG through the blood vessels under the near infrared spectroscopy-detector [14]. This method was an easier and more efficient way than standard techniques to detect and treat radiographic cerebral vasospasm after subarachnoid hemorrhage.…”