Bedside monitoring of cerebral blood flow in patients with acute hemispheric stroke

Objective: To test the practicability of a new double indicator dilution me thod for bedside monitoring of cerebral blood flow (CBF) and to assess the clinical value of CBF monitoring as a prognostic tool for outcome and in th erapy of elevated intracranial pressure (ICP) in patients with acute hemisp heric stroke. Design: Prospective study. Clinical evaluation of a new method, Setting: Neurological intensive care unit of a university hospital, Patients: Ten patients with acute complete middle cerebral artery territory - or hemispheric infarctions. interventions: Two combined fiberoptic thermistor catheters were placed in the right jugular bulb and in the thoracic aorta, Central venous injections of ice-cold indocyanine green dye were performed, CBF was estimated by cal culating the mean transit times of the cold bolus and dye, Measurements and Main Results: A total of 104 reproducible CBF measurements were obtained, No complications associated with the method were observed. Twelve pairs of measurements were performed within 30 mins with unchanged c linical conditions, The standard deviation of repeated measurements was 2.7 mL/100g/min; the interrater reliability was between 0.95 and 0.99. The med ian CBF in patients who died (n = 4) was lower (27 mL/100g/min) than in tho se who survived (n = 6) (45 mL/100g/min), Patients who died more frequently had low CBF values of <30 mL/100g/min (22 of 38; 58%) than patients who su rvived (10 of 54; 19%), A total of 37 CBF measurements were done during ICP elevation of >20 mm Hg, In patients who survived, ICP elevations were only associated with low CBF values in 5 of 26 events; whereas in patients who died, ICP elevations were associated with low CBF values in 8 of 11 events, Conclusions: The new double indicator dilution technique may be suitable fo r serial bedside CBF measurement, It is easy to perform and can be rapidly repeated in the ICU environment, Validation of the method by comparison wit h standard methods is needed. The preliminary data indicate that bedside mo nitoring of CBF may give prognostic information for outcome and may guide t herapy of elevated ICP in patients with malignant hemispheric infarction.