This study investigated whether comatose patients with greater duration and magnitude of clinically observed mean arterial pressure outside optimal mean arterial blood pressure have worse outcomes than those with mean arterial blood pressure closer to optimal mean arterial blood pressure calculated by bedside multimodal cerebral autoregulation monitoring using near-infrared spectroscopy.
Prospective observational study.
Neurocritical Care Unit of the Johns Hopkins Hospital.
Acutely comatose patients secondary to brain injury.
The cerebral oximetry index was continuously monitored with near-infrared spectroscopy for up to 3 days. Optimal mean arterial blood pressure was defined as that mean arterial blood pressure at the lowest cerebral oximetry index (nadir index) for each 24-hour period of monitoring. Kaplan-Meier analysis and proportional hazard regression models were used to determine if survival at 3 months was associated with a shorter duration of mean arterial blood pressure outside optimal mean arterial blood pressure and the absolute difference between clinically observed mean arterial blood pressure and optimal mean arterial blood pressure. A total 91 comatose patients were enrolled in the study. The most common etiology was intracerebral hemorrhage. Optimal mean arterial blood pressure could be calculated in 89 patients (97%), and the median optimal mean arterial blood pressure was 89.7 mm Hg (84.6–100 mm Hg). In multivariate proportional hazard analysis, duration outside optimal mean arterial blood pressure of greater than 80% of monitoring time (adjusted hazard ratio, 2.13; 95% CI, 1.04–4.41; p = 0.04) and absolute difference between clinically observed mean arterial blood pressure and optimal mean arterial blood pressure of more than 10 mm Hg (adjusted hazard ratio, 2.44; 95% CI, 1.21–4.92; p = 0.013) were independently associated with mortality at 3 months, after adjusting for brain herniation, admission Glasgow Coma Scale, duration on vasopressors and midline shift at septum.
Comatose neurocritically ill adults with an absolute difference between clinically observed mean arterial blood pressure and optimal mean arterial blood pressure greater than 10 mm Hg and duration outside optimal mean arterial blood pressure greater than 80% had increased mortality at 3 months. Noninvasive near-infrared spectroscopy-based bedside calculation of optimal mean arterial blood pressure is feasible and might be a promising tool for cerebral autoregulation oriented-therapy in neurocritical care patients.
1Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD.
2Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine. Baltimore, MD.
3Department of Anesthesiology, Universidad del Valle, School of Medicine, Cali, Colombia.
4Department of Anesthesiology, Northwestern University Feinberg, School of Medicine, Chicago, IL.
*See also p.1472.
Drs. Hogue and Ziai are senior authors.
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Supported, in part, by grant from the American Academy of Neurology/American Brain Foundation.
Dr. Rivera-Lara’s institution received funding from American Academy of Neurology/American Brain Foundation and equipment from a Covidien/Medtronic grant. Dr. Brown’s institution received funding from National Institutes of Health (NIH)/National Institute on Aging and Medtronic. Drs. Brown and Hogue received support for article research from the NIH. Dr. Hogue is the PI on an NIH-sponsored clinical study (R01 HL 92259); he received funding from Medtronic/Covidien, Dublin, IR (advisor and lecturer), Merck (Data Safety and Monitoring Board for unrelated drug trial); he serves as a consultant to Medtronic/Covidien and Ornim Medical, Foxborough, MA; he received other support from Medtronic in the form of a near-infrared spectroscopy sensor; and he disclosed off-label product use of autoregulation monitoring. Dr. Ziai received funding form HeadSense. The remaining authors have disclosed that they do not have any potential conflicts of interest.
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