Deriving the PRx and CPPopt from 0.2-Hz Data: Establishing Generalizability to Bedmaster Users.

OBJECTIVE: The objective was to explore the validity of industry-parameterized vital signs in the generation of pressure reactivity index (PRx) and optimal cerebral perfusion pressure (CPPopt) values. MATERIALS AND METHODS: Ten patients with intracranial pressure (ICP) monitors from 2008 to 2013 in a tertiary care hospital were included. Arterial blood pressure (ABP) and ICP were sampled at 240 Hz (of waveform data) and 0.2 Hz (of parameterized data produced by heuristic industry proprietary algorithms). 240-Hz ABP were filtered for pulse pressure and diastolic ABP within the limits of 20-150 mmHg. The PRx was calculated as Pearson's correlation coefficient using 10-s averages of ICP and ABP over a 5-min moving window with 80% overlap. For ease of comparison, we used the naming convention of BMx for PRx values derived from 0.2-Hz data. A 5-min median cerebral perfusion pressure (CPP) trend was calculated, PRx or BMx values divided and averaged into CPP bins spanning 5 mmHg. The minimum Y value (PRx or BMx) of the parabolic function fit to the resulting XY plot of 4 h of data was obtained, and updated every 1 min. Pearson's R correlations were calculated for each patient. Linear mixed-effects models were used with a random intercept to assess the overall correlation between the PRx (outcome) and the BMx (fixed effect) or the CPPopt-PRx (outcome) and the CPPopt-BMx (fixed effect). RESULTS: The overall correlation between the PRx and BMx was 0.78 based on the linear mixed effects models (p < 0.0001), and the overall correlation for the CPPopt-PRx and CPPopt-BMx based on the linear mixed effects models was 0.76 (p < 0.0001). One patient had low correlation of CPPopts derived from the PRx vs the BMx; this patient had the least number of hours of CPPopt data to compare. CONCLUSIONS: The BMx shows promise in CPPopt derivation against the validated PRx measure. If further developed, it could expand the capability of centers to derive CPPopt goals for use in clinical trials.

Bedside quantitative electroencephalography improves assessment of consciousness in comatose subarachnoid hemorrhage patients.

OBJECTIVE: Accurate behavioral assessments of consciousness carry tremendous significance in guiding management, but are extremely challenging in acutely brain-injured patients. We evaluated whether electroencephalography (EEG) and multimodality monitoring parameters may facilitate assessment of consciousness in patients with subarachnoid hemorrhage. METHODS: A retrospective analysis was performed of 83 consecutively treated adults with subarachnoid hemorrhage. All patients were initially comatose and had invasive brain monitoring placed. Behavioral assessments were performed during daily interruption of sedation and categorized into 3 groups based on their best examination as (1) comatose, (2) arousable (eye opening or attending toward a stimulus), and (3) aware (command following). EEG features included spectral power and complexity measures. Comparisons were made using bootstrapping methods and partial least squares regression. RESULTS: We identified 389 artifact-free EEG clips following behavioral assessments. Increasing central gamma, posterior alpha, and diffuse theta-delta oscillations differentiated patients who were arousable from those in coma. Command following was characterized by a further increase in central gamma and posterior alpha, as well as an increase in alpha permutation entropy. These EEG features together with basic neurological examinations (eg, pupillary light reflex) contributed heavily to a linear model predicting behavioral state, whereas brain physiology measures (eg, brain oxygenation), structural injury, and clinical course added less. INTERPRETATION: EEG measures of behavioral states provide distinctive signatures that complement behavioral assessments of patients with subarachnoid hemorrhage shortly after the injury. Our data support the hypothesis that impaired connectivity of cortex with both central thalamus and basal forebrain underlies decreasing levels of consciousness. Ann Neurol 2016;80:541-553.

Acute ischemic injury on diffusion-weighted magnetic resonance imaging after poor grade subarachnoid hemorrhage.

BACKGROUND: Poor clinical condition is the most important predictor of neurological outcome and mortality after subarachnoid hemorrhage (SAH). Rupture of an intracranial aneurysm was shown to be associated with acute ischemic brain injury in poor grade patients in autopsy studies and small magnetic resonance imaging series. METHODS: We performed diffusion-weighted magnetic resonance imaging (DWI) within 96 h of onset in 21 SAH patients with Hunt-Hess grade 4 or 5 enrolled in the Columbia University SAH Outcomes Project between July 2004 and February 2007. We analyzed demographic, radiological, clinical data, and 3 months outcome. RESULTS: Of the 21 patients 13 were Hunt-Hess grade 5, and eight were grade 4. Eighteen patients (86%) displayed bilateral and symmetric abnormalities on DWI, but not on computed tomography (CT). Involved regions included both anterior cerebral artery territories (16 patients), and less often the thalamus and basal ganglia (4 patients), middle (6 patients) or posterior cerebral artery territories (2 patients), or cerebellum (2 patients). At 1-year, 15 patients were dead (life support had been withdrawn in 6), 2 were moderately to severely disabled (modified Rankin Scale [mRS] = 4-5), and 4 had moderate-to-no disability (mRS = 1-3). CONCLUSIONS: Admission DWI demonstrates multifocal areas of acute ischemic injury in poor grade SAH patients. These ischemic lesions may be related to transient intracranial circulatory arrest, acute vasoconstriction, microcirculatory disturbances, or decreased cerebral perfusion from neurogenic cardiac dysfunction. Ischemic brain injury in poor grade SAH may be a feasible target for acute resuscitation strategies.

Evaluation of a revised Glasgow Coma Score scale in predicting long-term outcome of poor grade aneurysmal subarachnoid hemorrhage patients.

Although many scales attempt to predict outcome following aneurysmal subarachnoid hemorrhage (aSAH), none have achieved universal acceptance, and most scales in common use are not statistically derived. We propose a statistically validated scale for poor grade aSAH patients that combines the Hunt and Hess grades and the Glasgow Coma Scale (GCS) scores; we refer to this as the Poor Grade GCS (PGS). The GCS scores of 160 poor grade aSAH patients (Hunt and Hess Grades 4 and 5) were recorded throughout their hospital stay. Outcomes were assessed by the modified Rankin scale (mRS). Analysis of variance and the Chi-square test were used to guide an analysis of GCS breakpoints according to outcomes. Multivariable logistic regression analysis was used to assess the ability of the Hunt and Hess, GCS, World Federation of Neurological Surgeons Grading Scale, and the PGS to predict long-term outcome. Outcome analysis revealed significant breakpoints in admission GCS scores: PGS-A (GCS 10-12); PGS-B (GCS 8-9); PGS-C (GCS 5-7); PGS-D (GCS 3-4) (p<0.001). In surgical patients, 95.2% of PGS-A, 58.1% of PGS-B, 35.4% of PGS-C, and 28.6% of PGS-D had a favorable one-year outcome. When controlling for age, sex, and operation status, PGS was the only scale predictive of long-term outcome. The odds ratios (OR) for unfavorable outcome according to PGS admission scores (with PGS-A as the reference) were: PGS-B, OR=14.2 (95% CI 1.5-140.5); PGS-C, OR=38.5 (95% CI 4.2-340.0); and PGS-D, OR=63.4 (95% CI 5.6-707.1). In addition to PGS admission scores, an age of 70 or greater was a significant predictor of poor outcome with an OR of 7.5 (95% CI 1.8-30.7). No patients with a PGS-C or PGS-D over the age of 70 had a favorable long-term outcome. Therefore, elements of the Hunt and Hess and GCS can be combined into the PGS to predict long-term outcome in poor grade aSAH patients. However, patients with PGS-C and PGS-D over the age of 70 should be assessed carefully prior to definitive treatment.