Object Near-infrared spectroscopy (NIRS) offers noninvasive bedside measurement of direct regional cerebral arteriovenous (mixed) brain oxygenation. To validate the accuracy of this monitoring technique, the authors analyzed the statistical correlation of NIRS and CT perfusion with respect to regional cerebral blood flow (CBF) measurements. Methods The authors retrospectively reviewed all cases in which NIRS measurements were obtained at a single, academic neurointensive care unit from February 2008 to June 2011 in which CT perfusion was performed at the same time as NIRS data was collected. Regions of interest were obtained 2.5 cm below the NIRS bifrontal scalp probe on CT perfusion with an average volume between 2 and 4 ml, with mean CBF values used for purposes of analysis. Linear regression analysis was performed for NIRS and CBF values. Results The study included 8 patients (2 men, 6 women), 6 of whom suffered subarachnoid hemorrhage, 1 ischemic stroke, and 1 intracerebral hemorrhage and brain edema. Mean CBF measured by CT perfusion was 61 ml/100 g/min for the left side and 60 ml/100 g/min for the right side, while mean NIRS values were 75 on the right and 74 on the left. Linear regression analysis demonstrated a statistically significant probability value (p < 0.0001) comparing NIRS frontal oximetry and CT perfusion–obtained CBF values. Conclusions The authors demonstrated a linear correlation for frontal NIRS cerebral oxygenation measurements compared with regional CBF on CT perfusion imaging. Thus, frontal NIRS cerebral oxygenation measurement may serve as a useful, noninvasive, bedside intensive care unit monitoring tool to assess brain oxygenation in a direct manner.

Stroke is a common, potentially devastating disease with potential high morbidity and mortality. Recognition at the onset of acute ischemic stroke is pivotal to changing outcomes such as intravenous thrombolysis. Stroke monitoring is a burgeoning field with various methods described and newer devices that aid in detecting acute or worsening ischemia that can lead to improved bedside and intensive care unit management. This article describes various methods of bedside stroke monitoring including newer techniques of intracranial pressure monitoring using the pressure reactivity index and compensatory reserve index to detect changes in autoregulatory states, noninvasive intracranial pressure monitoring, quantitative EEG with alpha-delta ratio, transcranial Doppler, methods of arteriovenous brain oxygen monitoring such as jugular venous oxygen and near-infrared spectroscopy, invasive brain oxygen probes such as Licox™ (brain tissue O₂), cerebral blood flow probe (CBF Hemedex™) and cerebral microdialysis.