‘On-Line’ Alterations of Contralateral Jugular Blood Gas Profile during Carotid Clamping

Abstract

The aim of this work was to record the metabolic status of the brain (pH, PCO₂ and PO₂) during carotid endarterectomy (CEA), with the use of an intravascular multiparameter sensor (Paratrend 7) via retrograde catheterization of the contralateral jugular vein. Twenty-four patients with ASA grades II and III scheduled for CEA were included in the study. After induction of anesthesia, the contralateral internal jugular vein was punctured retrogradely and the sensor was introduced. During clamping, pH became persistently more acidotic (7.34–7.31; p < 0.05), PCO₂ was elevated (43.2–46.8 mm Hg; p < 0.05) while most of the patients showed a non-significant decrease in PjvO₂/SjvO₂ (jv = jugular venous). Correlation with clamping time or stump pressure was not significant. Unclamping was followed by a short period (5– 9 min) of decrease in pH and elevation of PCO₂ (7.30–7.22; p < 0.05, and 48.0–52.5 mm Hg; p < 0.05, respectively). PjvO₂ was significantly elevated (51.8–58.0 mm Hg; p < 0.001) after the restoration of flow. The study suggests that local CO₂ creates conditions for compensation of flow after the application of a carotid clamp. We consider that this monitoring technique, after further validation, may provide useful information.