Brain interstitial fluid TNF-alpha after subarachnoid hemorrhage

OBJECTIVE

TNF-alpha is an inflammatory cytokine that plays a central role in promoting the cascade of events leading to an inflammatory response. Recent studies have suggested that TNF-alpha may play a key role in the formation and rupture of cerebral aneurysms, and that the underlying cerebral inflammatory response is a major determinate of outcome following subrarachnoid hemorrhage (SAH).

METHODS

We studied 14 comatose SAH patients who underwent multimodality neuromonitoring with intracranial pressure (ICP) and cerebral microdialysis as part of their clinical care. Continuous physiological variables were time-locked every 8h and recorded at the same point that brain interstitial fluid TNF-alpha was measured in brain microdialysis samples. Significant associations were determined using generalized estimation equations.

RESULTS

Each patient had a mean of 9 brain tissue TNF-alpha measurements obtained over an average of 72h of monitoring. TNF-alpha levels rose progressively over time. Predictors of elevated brain interstitial TNF-alpha included higher brain interstitial fluid glucose levels (beta=0.066, p<0.02), intraventricular hemorrhage (beta=0.085, p<0.021), and aneurysm size >6mm (beta=0.14, p<0.001). There was no relationship between TNF-alpha levels and the burden of cisternal SAH; concurrent measurements of serum glucose, or lactate-pyruvate ratio.

INTERPRETATION

Brain interstitial TNF-alpha levels are elevated after SAH, and are associated with large aneurysm size, the burden of intraventricular blood, and elevation brain interstitial glucose levels.

Cerebral inflammatory response and predictors of admission clinical grade after aneurysmal subarachnoid hemorrhage

Poor admission clinical grade is the most important determinant of outcome after aneurysmal subarachnoid hemorrhage (aSAH); however, little attention has been focused on independent predictors of poor admission clinical grade. We hypothesized that the cerebral inflammatory response initiated at the time of aneurysm rupture contributes to ultra-early brain injury and poor admission clinical grade. We sought to identify factors known to contribute to cerebral inflammation as well as markers of cerebral dysfunction that were associated with poor admission clinical grade. Between 1997 and 2008, 850 consecutive SAH patients were enrolled in our prospective database. Demographic data, physiological parameters, and location and volume of blood were recorded. After univariate analysis, significant variables were entered into a logistic regression model to identify significant associations with poor admission clinical grade (Hunt-Hess grade 4-5). Independent predictors of poor admission grade included a SAH sum score >15/30 (odds ratio [OR] 2.3, 95% confidence interval [CI] 1.5-3.6), an intraventricular hemorrhage sum score >1/12 (OR 3.1, 95% CI 2.1-4.8), aneurysm size >10mm (OR 1.7, 95% CI 1.1-2.6), body temperature 38.3 degrees C (OR 2.5, 95% CI 1.1-5.4), and hyperglycemia >200mg/dL (OR 2.7, 95% CI 1.6-4.5). In a large, consecutive series of prospectively enrolled patients with SAH, the inflammatory response at the time of aneurysm rupture, as reflected by the volume and location of the hemoglobin burden, hyperthermia, and perturbed glucose metabolism, independently predicts poor admission Hunt-Hess grade. Strategies for mitigating the inflammatory response to aneurysmal rupture in the hyper-acute setting may improve the admission clinical grade, which may in turn improve outcomes.

PREDICTORS OF GLOBAL COGNITIVE IMPAIRMENT 1 YEAR AFTER SUBARACHNOID HEMORRHAGE

OBJECTIVE

We sought to determine the frequency, risk factors, and impact on functional outcome and quality of life (QOL) of global cognitive impairment 1 year after subarachnoid hemorrhage.

METHODS

We prospectively evaluated global cognitive status 3 and 12 months after hospitalization with the Telephone Interview for Cognitive Status in 232 subarachnoid hemorrhage survivors. Cognitive impairment was defined as a score of 30 or less (scaled 0 = worst, 51 = best). Logistic regression was performed to calculate adjusted odds ratios (AORs) for impairment at 1 year. Basic activities of daily living were evaluated with the Barthel Index, instrumental activities of daily living were assessed with the Lawton scale, and QOL was evaluated with the Sickness Impact Profile.

RESULTS

The frequency of cognitive impairment was 27% at 3 months and 21% at 12 months. After the effects of age, education, and race/ethnicity were controlled for, risk factors for cognitive impairment at 12 months included anemia treated with transfusion (AOR, 3.4; P = 0.006), any temperature level higher than 38.6°C (AOR, 2.7; P = 0.016), and delayed cerebral ischemia (AOR, 3.6; P = 0.01). Among cognitively impaired patients at 3 months, improvement at 1 year occurred in 34% and was associated with more than 12 years of education and the absence of fever higher than 38.6°C during hospitalization (P = 0.015). Patients with cognitive impairment at 1 year had worse concurrent QOL and less ability to perform instrumental and basic activities of daily living (all P &lt; 0.001).

CONCLUSION

Global cognitive impairment affects more than 20% of subarachnoid hemorrhage survivors at 1 year, is predicted by fever, anemia treated with transfusion, and delayed cerebral ischemia, and adversely affects functional recovery and QOL.

Relationship between energy balance and complications after subarachnoid hemorrhage

BACKGROUND

Subarachnoid hemorrhage patients are hypermetabolic and at risk for developing medical complications. A relationship was hypothesized between energy balance and complications following subarachnoid hemorrhage.

METHODS

Fifty-eight consecutive poor-grade subarachnoid hemorrhage patients (mean age, 58; range, 26-86; 66% women) were studied between 2005 and 2007. Caloric intake and energy expenditure were assessed. In-hospital complications over the first 14 days posthemorrhage were defined as renal failure, fever (>38.3 degrees C), any infection, anemia, hyperglycemia (>11 mmol/L), and myocardial infarction. Energy balance was calculated by subtracting energy expenditure from caloric intake.

RESULTS

Enteral nutrition was begun 1 day posthemorrhage (range, 0-5 days). Recommended (mean +/- SD) caloric intake was 28 +/- 3 kcal/kg/d, and the actual was 14 +/- 5 kcal/kg/d. Enteral nutrition accounted for 67% of caloric intake; propofol and dextrose infusions accounted for 33% of caloric intake. Cumulative energy balance over the first 7 days was -117 +/- 53 kcal/kg. The average energy balance during the first 7 days after subarachnoid hemorrhage significantly correlated with the total number of infectious complications (r = -0.5, P < .001) but not medical complications (r = -0.2, P = .1). After adjustment for Hunt-Hess grade, fever, hyperglycemia, and anemia, negative energy balance during the first 7 days after subarachnoid hemorrhage correlated with the number of infectious complications (P = .01).

CONCLUSIONS

Infectious complications after subarachnoid hemorrhage are associated with negative energy balance. Studies are needed to better understand the impact of negative energy balance on outcome after subarachnoid hemorrhage.

Transcranial Doppler for predicting delayed cerebral ischemia after subarachnoid hemorrhage

OBJECTIVE

Transcranial Doppler (TCD) is widely used to monitor the temporal course of vasospasm after subarachnoid hemorrhage (SAH), but its ability to predict clinical deterioration or infarction from delayed cerebral ischemia (DCI) remains controversial. We sought to determine the prognostic utility of serial TCD examination after SAH.

METHODS

We analyzed 1877 TCD examinations in 441 aneurysmal SAH patients within 14 days of onset. The highest mean blood flow velocity (mBFV) value in any vessel before DCI onset was recorded. DCI was defined as clinical deterioration or computed tomographic evidence of infarction caused by vasospasm, with adjudication by consensus of the study team. Logistic regression was used to calculate adjusted odds ratios for DCI risk after controlling for other risk factors.

RESULTS

DCI occurred in 21% of patients (n = 92). Multivariate predictors of DCI included modified Fisher computed tomographic score (P = 0.001), poor clinical grade (P = 0.04), and female sex (P = 0.008). After controlling for these variables, all TCD mBFV thresholds between 120 and 180 cm/s added a modest degree of incremental predictive value for DCI at nearly all time points, with maximal sensitivity by SAH day 8. However, the sensitivity of any mBFV more than 120 cm/s for subsequent DCI was only 63%, with a positive predictive value of 22% among patients with Hunt and Hess grades I to III and 36% in patients with Hunt and Hess grades IV and V. Positive predictive value was only slightly higher if mBFV exceeded 180 cm/s.

CONCLUSION

Increased TCD flow velocities imply only a mild incremental risk of DCI after SAH, with maximal sensitivity by day 8. Nearly 40% of patients with DCI never attained an mBFV more than 120 cm/s during the course of monitoring. Given the poor overall sensitivity of TCD, improved methods for identifying patients at high risk for DCI after SAH are needed.

Defining vasospasm after subarachnoid hemorrhage: what is the most clinically relevant definition?

BACKGROUND AND PURPOSE

Vasospasm is an important complication of subarachnoid hemorrhage, but is variably defined in the literature.

METHODS

We studied 580 patients with subarachnoid hemorrhage and identified those with: (1) symptomatic vasospasm, defined as clinical deterioration deemed secondary to vasospasm after other causes were eliminated; (2) delayed cerebral ischemia (DCI), defined as symptomatic vasospasm, or infarction on CT attributable to vasospasm; (3) angiographic spasm, as seen on digital subtraction angiography; and (4) transcranial Doppler (TCD) spasm, defined as any mean flow velocity >120 cm/sec. Logistic regression analysis was performed to test the association of each definition of vasospasm with various hospital complications, and 3-month quality of life (sickness impact profile), cognitive status (telephone interview of cognitive status), instrumental activities of daily living (Lawton score), and death or severe disability at 3 months (modified Rankin scale score 4-6), after adjustment for covariates.

RESULTS

Symptomatic vasospasm occurred in 16%, DCI in 21%, angiographic vasospasm in 31%, and TCD spasm in 45% of patients. DCI was statistically associated with more hospital complications (N=7; all P<0.05) than symptomatic spasm (N=4), angiographic spasm (N=1), or TCD vasospasm (N=1). Angiographic and TCD vasospasm were not related to any aspect of clinical outcome. Both symptomatic vasospasm and DCI were related to reduced instrumental activities of daily living, cognitive impairment, and poor quality of life (all P<0.05). However, only DCI was associated with death or severe disability at 3 months (adjusted OR, 2.2; 95% CI, 1.2-3.9; P=0.007).

CONCLUSIONS

DCI is a more clinically meaningful definition than either symptomatic deterioration alone or the presence of arterial spasm by angiography or TCD.

RESUSCITATION AND CRITICAL CARE OF POOR-GRADE SUBARACHNOID HEMORRHAGE

AS OUTCOMES HAVE improved for patients with aneurysmal subarachnoid hemorrhage, most mortality and morbidity that occur today are the result of severe diffuse brain injury in poor-grade patients. The premise of this review is that aggressive emergency cardiopulmonary and neurological resuscitation, coupled with early aneurysm repair and advanced multimodality monitoring in a specialized neurocritical care unit, offers the best approach for achieving further improvements in subarachnoid hemorrhage outcomes. Emergency care should focus on control of elevated intracranial pressure, optimization of cerebral perfusion and oxygenation, and medical and surgical therapy to prevent rebleeding. In the postoperative period, advanced monitoring techniques such as continuous electroencephalography, brain tissue oxygen monitoring, and microdialysis can detect harmful secondary insults, and may eventually be used as end points for goal-directed therapy, with the aim of creating an optimal physiological environment for the comatose injured brain. As part of this paradigm shift, it is essential that aggressive surgical and medical support be linked to compassionate end-of-life care. As neurosurgeons become confident that comfort care can be implemented in a straightforward fashion after a failed trial of early maximal intervention, the usual justification for withholding treatment (survival with neurological devastation) becomes less relevant, and lives may be saved as more patients recover beyond expectations.

Frequency and clinical impact of asymptomatic cerebral infarction due to vasospasm after subarachnoid hemorrhage

OBJECT

The authors sought to determine frequency, risk factors, and impact on outcome of asymptomatic cerebral infarction due to vasospasm after subarachnoid hemorrhage (SAH).

METHODS

The authors prospectively studied 580 patients with SAH admitted to their center between July 1996 and May 2002. Delayed cerebral ischemia (DCI) from vasospasm was defined as 1) a new focal neurological deficit or decrease in level of consciousness, 2) a new infarct revealed by follow-up CT imaging, or both, after excluding causes other than vasospasm. Outcome at 3 months was assessed using the modified Rankin Scale.

RESULTS

Delayed cerebral ischemia occurred in 121 (21%) of 580 patients. Of those with DCI, 36% (44 patients) experienced neurological deterioration without a corresponding infarct, 42% (51 patients) developed an infarct in conjunction with neurological deterioration, and 21% (26 patients) had a new infarct on CT without concurrent neurological deterioration. In a multivariate analysis, risk factors for asymptomatic DCI included coma on admission, placement of an external ventricular drain, and smaller volumes of SAH (all p < or = 0.03). Patients with asymptomatic DCI were less likely to be treated with vasopressor agents than those with symptomatic DCI (64 vs 86%, p = 0.01). After adjusting for clinical grade, age, and aneurysm size, the authors found that there was a higher frequency of death or moderate-to-severe disability at 3 months (modified Rankin Scale Score 4-6) in patients with asymptomatic DCI than in patients with symptomatic DCI (73 vs 40%, adjusted odds ratio 3.9, 95% confidence interval 1.3-12.0, p = 0.017).

CONCLUSIONS

Approximately 20% of episodes of DCI after SAH are characterized by cerebral infarction in the absence of clinical symptoms. Asymptomatic DCI is particularly common in comatose patients and is associated with poor outcome. Strategies directed at diagnosing and preventing asymptomatic infarction from vasospasm in patients with poor-grade SAH are needed.

Safety and feasibility of percutaneous tracheostomy performed by neurointensivists

INTRODUCTION

We evaluated the effects of a change from routine surgical tracheostomy (ST), performed primarily by ENT surgeons, to bedside percutaneous tracheostomy (PT) performed by neurointensivists.

METHODS

The first 67 PT procedures performed by neurointensivists were retrospectively reviewed, and compared with 68 consecutive ST procedures performed during the previous year. Demographics, severity of illness, procedural complications, incidence of ventilator-associated pneumonia (VAP), duration of mechanical ventilation (DMV), length of stay (LOS), and hospital charges were evaluated.

RESULTS

Age, race, gender, neurological diagnoses, comorbid illnesses, and Glasgow coma scale on admission and the day of tracheostomy were similar. Procedural complications occurred in 8% of PT patients and 9% of ST patients, including clinically significant bleeding, transient loss of the airway, ICP rise requiring treatment, or acute lung injury (P = 0.3). PT was performed earlier than ST (median [interquartile range] ventilator day 8 [4-11] vs. 12 [8-18], P = 0.001). Median DMV was shorter in the PT cohort (19 [10-27] vs. 24 [16-33] days, P = 0.02), as was median ICU LOS (15 [9-21] vs. 19 [12-27] days, P = 0.01). ICU charges (US dollars) were lower in the PT cohort (median $123,404 vs. $156,311, P = 0.01). Trends toward less VAP, shorter hospital LOS, and lower total hospital charges among patients receiving PT did not achieve significance.

CONCLUSIONS

PT performed by neurointensivists was safe compared to ST. Timely PT by neurointensivists may offer significant advantages in terms of ventilator weaning, ICU LOS, and the cost of care.

A Randomized, Double-Blind, Placebo-Controlled Pilot Study of Simvastatin in Aneurysmal Subarachnoid Hemorrhage

Background and Purpose— Studies suggest statins ameliorate aneurysmal subarachnoid hemorrhage (SAH)-induced cerebral vasospasm and ischemic complications. We tested safety and feasibility of simvastatin 80 mg/d for vasospasm prevention in SAH patients.

Methods— Thirty-nine statin-naïve Fisher grade 3 SAH subjects were double-blind randomized to receive simvastatin 80 mg/d (n=19) or placebo (n=20), stratified by Hunt and Hess grade. Primary end points were death and drug morbidity.

Results— Mortality was 3/20 in the placebo and 0/19 in the simvastatin group. Study drug was withdrawn in 1 subject in each treatment group for reversible liver enzyme or creatine phosphokinase elevation. Angiographically-confirmed vasospasm occurred in 8/20 placebo and 5/19 simvastatin-treated subjects. Vasospasm-related ischemic infarcts developed in 5/20 placebo and 2/19 simvastatin-treated subjects.

Conclusion— Simvastatin for the prevention of delayed cerebral ischemia is safe and feasible after SAH. A larger study is needed to test its efficacy.

Cardiac arrhythmias after subarachnoid hemorrhage: risk factors and impact on outcome

OBJECTIVE

Serious cardiac arrhythmias have been described in approximately 5% of patients after subarachnoid hemorrhage (SAH). The aim of this study was to identify the frequency, risk factors and clinical impact of cardiac arrhythmia after SAH.

METHODS

We prospectively studied 580 spontaneous SAH patients and identified risk factors and complications associated with the development of clinically significant arrhythmia. Multiple logistic regression analysis was used to calculate adjusted odds ratios for the effect of arrhythmia on hospital complications and 3-month outcome, as measured by the modified Rankin Scale, after controlling for age, neurological grade, APACHE-2 physiologic subscore, brain herniation and aneurysm size.

RESULTS

Arrhythmia occurred in 4.3% (n = 25) of patients. Atrial fibrillation and flutter were the most common arrhythmias, occurring in 76% (n = 19) of these patients. Admission predictors of cardiac arrhythmia included older age, history of arrhythmia and abnormal admission electrocardiogram (all p < 0.05). After adjusting for length of stay, hospital complications associated with arrhythmia included myocardial ischemia, hyperglycemia, and herniation (all p < 0.05). Arrhythmia was associated with an excess ICU stay of 5 days (p = 0.002). After adjusting for other predictors of outcome, arrhythmia was associated with an increased risk of death (adjusted OR 8.0, 95% confidence interval 1.9-34.0, p = 0.005), and death or severe disability (adjusted OR 6.9, 95% confidence interval 1.5-32.0, p = 0.014).

CONCLUSIONS

Clinically important arrhythmias, most often atrial fibrillation or flutter, occurred in 4% of SAH patients. Arrhythmias are associated with an increased risk of cardiovascular comorbidity, prolonged hospital stay and poor outcome or death after SAH, after adjusting for other predictors of poor outcome.