Introduction: Access to information about the integrity of autoregulation should be relevant to directing the care of patients following aneurysmal subarachnoid hemorrhage (SAH), especially if they are suspected of having delayed neurological deficits. By integrating continuous data streams such as cerebral blood flow (CBF) and mean arterial pressure we have gained access to potentially useful autoregulation information.
Methods: Aneurysmal SAH patients are candidates for the placement of a Hummingbird Monitoring system (Innerspace Medical) that in addition to tissue and ventricular ICP measurements provide access to thermal diffusion CBF (Hemedex) placed within the adjacent deep white matter. All data including continuous blood pressure measurements are acquired via the Component Neuromonitoring System (CNS) (Moberg Technologies). The fusion of data streams is an essential step that then permits advanced analysis of data.
Results: The thermal diffusion probe provides reliable access to high frequency quantitative CBF changes. Continuous recording of CBF data in excess of 10 days has been possible in many patients. In patients with good outcomes, mean CBF has not fluctuated with either subtle or dramatic changes of mean blood pressure. The most severely injured patients have demonstrated changes in CBF that correlate exactly with instantaneous changes of blood pressure indicating a loss of autoregulation.
Conclusions: Direct access to continuous thermal diffusion CBF information is a powerful clinical tool especially when integrated with other vital measurements such as mean blood pressure. Integrating these measurements makes information about the integrity of autoregulation readily accessible. Our experience demonstrates that cerebral autoregulation is not static and that patients may gain or lose control of this relationship following an aneurysm. With access to this continuously monitored information new strategies for altering patient management to improve outcome should become apparent...
Patient Care: This research could be used to alert doctors and nurses in real-time when patients start to lose autoregulation, and thereby enable the tailoring of treatment strategies in response to those changes and thereby lead to improved outcomes.
Learning Objectives: At the University of New Mexico we have successfully monitored and stored multimodal data for ~200 patients over the last three years. Form this experience we have developed a new approach to monitor autoregulation. By the conclusion of this session, the participants should be able to: 1) Describe the importance of continuous multimodal monitoring in the assessment of autoregulation; 2) Learn how the continual evaluation of CBF autoregulation may lead to improved treatment strategies; and 3) Identify potential ways in which this information can be used to evaluate the effectiveness of therapies in restoring autoregulation