Abstract TP537: Jugular Bulb Microdialysis in Subarachnoid Hemorrhage

Abstract

Introduction: Metabolic perturbations are common in patients with subarachnoid hemorrhage (SAH) and contribute to patient outcome. Cerebral microdialysis (CMD), used for monitoring of poor grade SAH patients, is intracranial invasive and highly regional, depending on proximity to lesions. Microdialysis of jugular bulb venous drainage has not been attempted in this patient group and it may give a measure of global cerebral metabolism detecting critical events potentially missed by regional monitoring. Methods: Adult SAH patients were included at admission when local clinical guidelines prompted extended multimodal neuromonitoring (impaired consciousness and poor grade SAH). Patients were monitored using non-dominant frontal CMD combined with an intracranial pressure (ICP) and brain oxygen tension (PbtO 2 ) probe in a double lumen bolt (Raumedic®) as well as dominant jugular bulb microdialysis for a mean period of 5 days. Jugular bulb lactate/pyruvate ratio (LPR) and intracranial derived measurements were analysed for correlation. 6 month modified Rankin scale (mRs) was assessed. Results: Twelve patients were included (mean age 62 years, mean mRs 3.7). There were no complications related to jugular bulb access. Of 1218 monitoring hours, 131 displayed elevated jugular bulb LPR (>20), 133 elevated ICP (>20 mmHg) and 287 reduced PbtO 2 (<20 mmHg). Periods of co-variation were seen in selected patients, but no significant correlations between jugular bulb LPR vs. cerebral LPR (r=-0.07, p=0.014), jugular bulb LPR vs. ICP (r=-0.03, p=0.72) or jugular bulb LPR vs. PbtO 2 (r=0.08, p=0.16) were found in Spearman analysis of critical periods. Concerning jugular LPR vs. mRs the study was underpowered (r=-0.36, p=0.27). Conclusions: Intracranial regional monitoring events were not mirrored in jugular bulb LPR and periods of metabolic perturbations seen in jugular bulb LPR passed without consistent indication from regional modalities. Metabolic disturbances are potentially missed by regional monitoring in SAH.