Abstract 8899: Mechanism for Dobutamine-Induced Hyperdynamic Transmission to the Relief of Focal Cerebral Ischemia Affected by Vasospasm after Subarachnoid Hemorrhage
Therapeutic hemodynamic augmentation by increasing cardiac output (CO) with dobutamine (DOB) is a valuable method of elevating regional cerebral blood flow and oxygenation in the dysautoregulated vascular territories by vasospasm following aneurysmal subarachnoid hemorrhage (SAH). In a prospective study, we assessed the effect of DOB-induced hyperdynamic therapy on regional cerebral oxygenation (rSO2) for reversing spasm symptoms, using an advanced integrative monitoring incorporated with uncalibrated continuous pulse contour CO analysis and multi-channel near-infrared spectroscopy (Edwards, Irvine, CA). Fifty-five consecutive patients with SAH treated surgically within 24 hours of ictus and diagnosed to have symptomatic vasospasm between postoperative days 4 and 14 were investigated. For medical treatment, DOB was administered at an initial dose of 3 μg/kg/min and then increased in 3 μg/kg/min increments until resolution of the symptoms (“hyperdynamic therapy”). Real-time CO and rSO2 changes during the therapy in conjunction with the assessment of neurological improvements were analyzed. A total of 225 DOB dose increment challenges were performed with a maximum dose of 11.0 ± 3.1 μg/kg/min. In spasm-affected territories, decreased and/or fluctuating rSO2 was detected compared with recordings in other brain regions. Patients who exhibited rapid elevation of CO by DOB challenges had subsequent uptake and stabilization of rSO2 followed by improvement of the symptoms. A fairly strong relationship was found between peak CO slope and rSO2 elevation during each DOB challenge (r = .79, P <0.0001), while a poor correlation was found between peak CO change and rSO2 (r= .33, P=0.09). Area under the ROC curve to discriminate neurological responders to DOB was higher for peak CO slope (0.86±0.08) than for peak CO (0.65±0.12) (P <0.05). Values of average peak CO slope of 0.007 predicted neurological improvement with DOB therapy, with 83% specificity and 70% sensitivity. Maximal hemodynamic acceleration rather than the peak CO values plays a key role of DOB hyperdynamic therapy in relieving focal cerebral ischemia/microvascular circulation and associated symptoms in patients suffering from vasospasm after SAH.
- © 2010 by American Heart Association, Inc.