Application of the FloTrac™ arterial pressure-based continuous cardiac output monitor to dobutamine-induced hyperdynamic therapy for cerebral vasospasm after subarachnoid hemorrhage

The aim of this study was to examine the usefulness of an uncalibrated radial arterial pressure-based cardiac output monitor (FloTrac™, Edwards Lifesciences. Irvine CA, USA) for dobutamine-induced hyperdynamic therapy in patients with cerebral vasospasm following subarachnoid hemorrhage (SAH). In 18 SAH patients diagnosed with vasospasm, the cardiac index (CI) was analyzed continuously via the radial FloTrac system. The time-course changes in hemodynamic variables following dobutamine infusion at each dose increment . (3-24 μg/kg/min) for reversing vasospasm-related delayed ischemic neurological deficit (DIND) and infarction were measured. At therapeutic dobutamine doses (3-15 μg/kg/min), CI increased immediately after the onset of each dose administration, which gradually fell to a level slightly higher than the baseline value. In all of the cases whose neurological findings were able to be examined, an improvement of DIND occurred during the phase of acute CI elevation. However at high-dose (20-24 μg/kg/min), dobutamine depressed stroke volume which was compensated for by increasing the pulse rate, thus raising CI only slightly from the baseline values. These data suggest that step-up increase of dobutamine dosage is not always effective in raising CI in patients suffering from post-SAH vasospasm, but rather may cause some adverse effects associated with increased myocardial oxygen consumption as evidenced by high-dose infusion. The less-invasive FloTrac™ system might be useful as a device for tracking trends in hemodynamic outcomes of hyperdynamic therapy.