The influence of contralateral carotid stenosis and occlusion on cerebral oxygen saturation during carotid artery surgery

Williams, I.M.; Mead, GE; Picton, A.; Farrell, Anne G.; Mortimer, A.J.; McCollum, Charles

doi:10.1016/s1078-5884(05)80112-1

Cited by 34 publications

(19 citation statements)

References 17 publications

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“…In adults, normal TOI values have been reported to range from 65% to 85%. 14,36 -41 Although a number of authors have compared NIRS with other techniques such as jugular bulb oxygen saturation (SjO 2 ), transcranial Doppler ultrasonography and somatosensory-evoked potential 15,37,[42][43][44][45][46][47][48][49][50][51][52][53][54][55][56] or with neurologic events, few have attempted to define an absolute threshold for ischemia. 13,14,16,17,46,[57][58][59] Most studies of this type using NIRS make no attempt to correct for extracranial contributions to signal changes.…”

Section: Discussionmentioning

confidence: 99%

Tissue Oxygen Index

Al-Rawi

Kirkpatrick

2006

Stroke

149

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Background and Purpose-To date, the clinical application of near infrared spectroscopy in the adult brain has been limited. The NIRO 300 (Hamamatsu Photonics) provides a continuous measurement of tissue oxygen index (TOI) using spatially resolved spectroscopy. Although TOI reflects cerebral oxygenation to a high degree of sensitivity and specificity, to become a useful clinical tool, thresholds for cerebral ischemia need to be defined. This study has attempted to identify a quantifiable TOI threshold for ischemia in the adult brain. Methods-One hundred sixty-seven patients undergoing carotid endarterectomy were studied. The NIRO 300 was incorporated into an established multimodal monitoring system enabling observations of cerebral hemodynamic changes under highly controlled conditions. Changes in TOI (%⌬TOI) on clamping the internal carotid artery were compared with intracranial blood flow (middle cerebral artery flow velocity) and cerebral function monitoring to identify and quantify periods of cerebral ischemia. Results-Significant correlation was seen between changes in middle cerebral artery flow velocity and ⌬TOI on clamping (rϭ0.74, Pϭ0.0001). Thirty-one patients showed cerebral ischemia on internal carotid artery clamping as defined by a sustained fall in cerebral function monitoring. A threshold for %⌬TOI of Ϫ13 was identified, above which no patients showed any evidence of ischemia on clamping. This threshold provided 100% sensitivity and 93.2% specificity for patients satisfying the preset criteria for cerebral ischemia. Conclusions-These data demonstrate the potential to identify TOI-quantified thresholds for cerebral ischemia in the adult brain and thus improve the clinical use of near infrared spectroscopy. Our observations have defined a drop in TOI (13%) that can be adopted as a threshold for severe cerebral ischemia with high sensitivity and specificity. Key Words: carotid endarterectomy Ⅲ cerebral ischemia Ⅲ near infrared spectroscopy Ⅲ spatially resolved spectroscopy Ⅲ tissue oxygen index O ptical methods based on near-infrared spectroscopy (NIRS) can be used to monitor hemodynamic variables in the clinical setting. 1 Applications include monitors of fetal physiology, 2-4 during cardiac surgery, 5,6 muscle function, 7-10 and neonatal, 11 pediatric, 12 and adult brain. [13][14][15][16][17][18][19] A number of NIRS instruments are now available that detect changes in optical attenuation from several wavelengths of light, and although a variety of algorithms have been applied to attempt quantification, accuracy of these instruments remains a concern.The NIRO 300 (Hamamatsu Photonics) provides a continuous online measurement of tissue oxygen index (TOI) using spatially resolved spectroscopy. 20,21 We have previously determined that TOI reflects cerebral oxygenation to a high degree of sensitivity and specificity during carotid surgery, 20 an indication that NIRS can show clinically relevant estimations of cerebral hemodynamic and oxygen changes in the adult head (Figure 1). However, there are no da...

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Section: Discussionmentioning

confidence: 99%

Tissue Oxygen Index

Al-Rawi

Kirkpatrick

2006

Stroke

149

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“…20 Thus, NIRS allows real-time changes in CBO and rCBF to be characterized continuously, al-though it does not measure baseline rCBF. Near-infrared spectroscopy has been used to monitor changes in hemodynamic status, which have been induced by a variety of neurosurgical procedures and functional tasks that cause both decreases 1,6,7,9,[11][12][13]15,18,[27][28][29]31,32,46,47,52 and increases 8,19,21,40,[42][43][44][45] in rCBF. Simultaneous measurements conducted using NIRS and PET scanning have demonstrated that the hemodynamic status estimated with NIRS was consistent with PET results.…”

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confidence: 99%

Evaluation of extracranial—intracranial arterial bypass function by using near-infrared spectroscopy

Murata¹,

Katayama²,

Sakatani³

et al. 2003

Journal of Neurosurgery

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“…The cerebral oximeter used in our study has already compared favorably with other valid techniques such as transcranial Doppler imaging, electroencephalography (EEG), and evaluation of somatosensory evoked potentials (SSEPs) for determining cerebral malperfusion. Williams and colleagues (16) have demonstrated that there is a good correlation between the decrease in the rSO 2 and the percentage of change in the peak transcranial Doppler velocity in patients with contralateral carotid stenosis and occlusion. Levy and associates (17) have shown that, in patients undergoing tests for automatic defibrillator placement, EEG changes are correlated with changes in cerebral oxygenation.…”

Section: Discussionmentioning

confidence: 99%

“…Several investigators have shown that a decrease in regional cerebral oxygen saturation (rSO 2 ) is a predictor of cerebral injury (16–20). The particular near‐infrared spectroscopy (NIRS) system used in our study monitors the critical balance between the rSO 2 and cerebral oxygen consumption.…”

Section: Discussionmentioning

confidence: 99%