Biomaterial Database

Cerebral monitoring during carotid endarterectomy--a comparison between electroencephalography, transcranial cerebral oximetry and carotid stump pressure. 2007

K Botes, and D A Le Roux, and J Van Marle

Medi-Clinic Unit for Peripheral Vascular Surgery, Department of Surgery, Pretoria Academic Hospital and University of Pretoria.

OBJECTIVE Various modalities are used for cerebral monitoring during carotid endarterectomy (CEA). The aim of this study was to evaluate whether transcranial cerebral oximetry (TCO) and carotid stump pressure (SP) are as accurate as electroencephalography (EEG) for monitoring cerebral ischaemia during carotid cross-clamping. METHODS One hundred consecutive patients who underwent CEA were studied with continuous and simultaneous EEG and TCO. SP was measured for each patient. The percentage decrease of oxygenation on TCO was calculated during cross-clamping and surgery. EEG findings were used as the benchmark to detect cerebral ischaemia and were the indication for insertion of a temporary shunt. The relationship with TCO was observed in terms of percentage decrease in oxygenation. RESULTS A total of 6 patients were shunted on the basis of their EEG changes. TCO changed more than 20% in these 6 patients, but an additional 12 patients had TCO changes with a normal EEG. This correlated with a decrease in blood pressure (BP) and was corrected by increasing the BP. The positive predictive values (PPVs) and negative predictive values (NPVs) for shunting based on TCO (as compared with EEG) were 33% and 100% respectively. Thirty-four patients had SP <50 mmHg, of whom 4 were shunted based on EEG changes. Two of 66 patients with SP >50 mmHg were shunted based on EEG changes. If a shunting policy had been based on a SP of 50 mmHg, 30 patients would have been shunted unnecessarily (PPV 12%), whereas the non-requirement for a shunt was predicted correctly in 64 of 66 patients (NPV 97%). There were 2 major strokes: 1 contralateral on day 3 in a patient with bilateral severe stenoses, and 1 ipsilateral in a nonshunted patient with normal EEG, TCO and SP >50 mmHg. CONCLUSIONS Compared with EEG, TCO is a practical and non-invasive monitoring system with a high sensitivity (100%) but a low specificity. TCO is more sensitive to a drop in BP and responds earlier to these changes than EEG. SP should not be used as the sole predictor for shunting during CEA.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D008991	Monitoring, Physiologic	The continuous measurement of physiological processes, blood pressure, heart rate, renal output, reflexes, respiration, etc., in a patient or experimental animal; includes pharmacologic monitoring, the measurement of administered drugs or their metabolites in the blood, tissues, or urine.	Patient Monitoring,Monitoring, Physiological,Physiologic Monitoring,Monitoring, Patient,Physiological Monitoring
D010092	Oximetry	The determination of oxygen-hemoglobin saturation of blood either by withdrawing a sample and passing it through a classical photoelectric oximeter or by electrodes attached to some translucent part of the body like finger, earlobe, or skin fold. It includes non-invasive oxygen monitoring by pulse oximetry.	Pulse Oximetry,Oximetry, Pulse,Oximetries,Oximetries, Pulse,Pulse Oximetries
D010101	Oxygen Consumption	The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)	Consumption, Oxygen,Consumptions, Oxygen,Oxygen Consumptions
D002339	Carotid Arteries	Either of the two principal arteries on both sides of the neck that supply blood to the head and neck; each divides into two branches, the internal carotid artery and the external carotid artery.	Arteries, Carotid,Artery, Carotid,Carotid Artery
D002540	Cerebral Cortex	The thin layer of GRAY MATTER on the surface of the CEREBRAL HEMISPHERES that develops from the TELENCEPHALON and folds into gyri and sulci. It reaches its highest development in humans and is responsible for intellectual faculties and higher mental functions.	Allocortex,Archipallium,Cortex Cerebri,Cortical Plate,Paleocortex,Periallocortex,Allocortices,Archipalliums,Cerebral Cortices,Cortex Cerebrus,Cortex, Cerebral,Cortical Plates,Paleocortices,Periallocortices,Plate, Cortical
D002545	Brain Ischemia	Localized reduction of blood flow to brain tissue due to arterial obstruction or systemic hypoperfusion. This frequently occurs in conjunction with brain hypoxia (HYPOXIA, BRAIN). Prolonged ischemia is associated with BRAIN INFARCTION.	Cerebral Ischemia,Ischemic Encephalopathy,Encephalopathy, Ischemic,Ischemia, Cerebral,Brain Ischemias,Cerebral Ischemias,Ischemia, Brain,Ischemias, Cerebral,Ischemic Encephalopathies
D004569	Electroencephalography	Recording of electric currents developed in the brain by means of electrodes applied to the scalp, to the surface of the brain, or placed within the substance of the brain.	EEG,Electroencephalogram,Electroencephalograms
D005260	Female		Females