Hector Lantigua

NONCONVULSIVE SEIZURES AFTER SUBARACHNOID HEMORRHAGE: MULTIMODAL DETECTION AND OUTCOMES

Seizures have been implicated as a cause of secondary brain injury, but the systemic and cerebral physiologic effects of seizures after acute brain injury are poorly understood.

High-dose midazolam infusion for refractory status epilepticus

Objective: This study compares 2 treatment protocols allowing low vs high continuous IV midazolam (cIV-MDZ) doses. Methods: We compared adults with refractory status epilepticus treated with a protocol allowing for high-dose cIV-MDZ (n = 100; 2002–2011) with those treated with the previous lower-dose cIV-MDZ (n = 29; 1996–2000). We collected data on baseline characteristics, cIV-MDZ doses, seizure control, hospital course, and outcome. Results: Median maximum cIV-MDZ dose was 0.4 mg/kg/h (interquartile range [IQR] 0.2, 1.0) for the high-dose group and 0.2 mg/kg/h (IQR 0.1, 0.3) for the low-dose group (p < 0.001) with similar duration of infusion. Median time from status epilepticus onset to cIV-MDZ start was 1 day (IQR 1, 3) for the high-dose group and 2 days (IQR 1, 5) for the low-dose group (p = 0.016). “Withdrawal seizures” (occurring within 48 hours of discontinuation of cIV-MDZ) were less frequent in the high-dose group (15% vs 64%, odds ratio 0.10, 95% confidence interval 0.03–0.27). “Ultimate cIV-MDZ failure” (patients requiring change to a different cIV antiepileptic medication) and hospital complications were not different between groups. Hypotension was more frequent with higher cIV-MDZ doses but was not associated with worse outcome. Discharge mortality was lower in the high-dose group (40% vs 62%, odds ratio 0.34, 95% confidence interval 0.13–0.92 in multivariate analysis). Conclusions: High-dose cIV-MDZ treatment of refractory status epilepticus can be performed safely, is associated with a lower seizure rate after cIV-MDZ discontinuation, and may be associated with lower mortality than traditional lower-dose protocols. Classification of evidence: This study provides Class III evidence that midazolam at higher infusion rates is associated with a reduction in seizure recurrence within 48 hours after discontinuation and may be associated with lower mortality.

Subarachnoid Hemorrhage International Trialists Data Repository (SAHIT)

The outcome of patients with aneurysmal subarachnoid hemorrhage (SAH) has improved slowly over the past 25 years. This improvement may be due to early aneurysm repair by endovascular or open means, use of nimodipine, and better critical care management. Despite this improvement, mortality remains at about 40%, and many survivors have permanent neurologic, cognitive, and neuropsychologic deficits. Randomized clinical trials have tested pharmacologic therapies, but few have been successful. There are numerous explanations for the failure of these trials, including ineffective interventions, inadequate sample size, treatment side effects, and insensitive or inappropriate outcome measures. Outcome often is evaluated on a good-bad dichotomous scale that was developed for traumatic brain injury 40 years ago. To address these issues, we established the Subarachnoid Hemorrhage International Trialists (SAHIT) data repository. The primary aim of the SAHIT data repository is to provide a unique resource for prognostic analysis and for studies aimed at optimizing the design and analysis of phase III trials in aneurysmal SAH. With this aim in mind, we convened a multinational investigator meeting to explore merging individual patient data from multiple clinical trials and observational databases of patients with SAH and to create an agreement under which such a group of investigators could submit data and collaborate. We welcome collaboration with other investigators.

Early neurological deterioration after subarachnoid haemorrhage: risk factors and impact on outcome

Background Early neurological deterioration occurs frequently after subarachnoid haemorrhage (SAH). The impact on hospital course and outcome remains poorly defined. Methods We identified risk factors for worsening on the Hunt–Hess grading scale within the first 24 h after admission in 609 consecutively admitted aneurysmal SAH patients. Admission risk factors and the impact of early worsening on outcome was evaluated using multivariable analysis adjusting for age, gender, admission clinical grade, admission year and procedure type. Outcome was evaluated at 12 months using the modified Rankin Scale (mRS). Results 211 patients worsened within the first 24 h of admission (35%). In a multivariate adjusted model, early worsening was associated with older age (OR 1.02, 95% CI 1.001 to 1.03; p=0.04), the presence of intracerebral haematoma on initial CT scan (OR 2.0, 95% CI 1.2 to 3.5; p=0.01) and higher SAH and intraventricular haemorrhage sum scores (OR 1.05, 95% CI 1.03 to 1.08 and 1.1, 95% CI 1.01 to 1.2; p<0.001 and 0.03, respectively). Early worsening was associated with more hospital complications and prolonged length of hospital stay and was an independent predictor of death (OR 12.1, 95% CI 5.7 to 26.1; p<0.001) and death or moderate to severe disability (mRS 4–6, OR 8.4, 95% CI 4.9 to 14.5; p=0.01) at 1 year. Conclusions Early worsening after SAH occurs in 35% of patients, is predicted by clot burden and is associated with mortality and poor functional outcome at 1 year.

Hyperoxia may be related to delayed cerebral ischemia and poor outcome after subarachnoid haemorrhage.

Objective To determine the association between exposure to hyperoxia and the risk of delayed cerebral ischaemia (DCI) after subarachnoid haemorrhage (SAH). Methods We analysed data from a single centre, prospective, observational cohort database. Patient inclusion criteria were age ≥18 years, aneurysmal SAH, endotracheal intubation with mechanical ventilation, and arterial partial pressure of oxygen (PaO2) measurements. Hyperoxia was defined as the highest quartile of an area under the curve of PaO2, until the development of DCI (PaO2≥173 mm Hg). Poor outcome was defined as modified Rankin Scale 4–6 at 3 months after SAH. Results Of 252 patients, there were no differences in baseline characteristics between the hyperoxia and control group. Ninety-seven (38.5%) patients developed DCI. The hyperoxia group had a higher incidence of DCI (p<0.001) and poor outcome (p=0.087). After adjusting for modified Fisher scale, rebleeding, global cerebral oedema, intracranial pressure crisis, pneumonia and sepsis, hyperoxia was independently associated with DCI (OR, 3.16; 95% CI 1.69 to 5.92; p<0.001). After adjusting for age, Hunt–Hess grade, aneurysm size, Acute Physiology and Chronic Health Evaluation II score, rebleeding, pneumonia and sepsis, hyperoxia was independently associated with poor outcome (OR, 2.30; 95% CI 1.03 to 5.12; p=0.042). Conclusions In SAH patients, exposure to hyperoxia was associated with DCI. Our findings suggest that exposure to excess oxygen after SAH may represent a modifiable factor for morbidity and mortality in this population.

Tonic-Clonic Activity at Subarachnoid Hemorrhage Onset: Impact on Complications and Outcome

Objective Tonic-clonic activity (TCA) at onset complicates 3% to 21% of cases of subarachnoid hemorrhage (SAH). The impact of onset TCA on in-hospital complications, including seizures, remains unclear. One study associated onset TCA with poor clinical outcome at 6 weeks after SAH, but to our knowledge no other studies have confirmed this relationship. This study aims to assess the impact of onset TCA on in-hospital complications, poor functional outcome, mortality, and epilepsy at 3 months. Methods Analysis of a prospective study cohort of 1479 SAH patients admitted to Columbia University Medical Center between 1996 and 2012. TCA within 6 hours of hemorrhage onset was identified based on accounts of emergency care providers or family witnesses. Results TCA at onset was described in 170 patients (11%). Patients with onset TCA were younger (P = 0.002), presented more often with poor clinical grade (55% vs. 26%, P<0.001) and had larger amounts of cisternal, intraventricular, and intracerebral blood than those without onset TCA (all, P<0.001). After adjusting for known confounders, onset TCA was significantly associated with in-hospital seizures (OR 3.80, 95%-CI: 2.43–5.96, P<0.001), in-hospital pneumonia (OR 1.56, 95%-CI: 1.06–2.31, p = 0.02), and delayed cerebral ischemia (OR 1.77, 95%-CI: 1.21–2.58, P = 0.003). At 3 months, however, onset TCA was not associated with poor functional outcome, mortality, and epilepsy after adjusting for age, admission clinical grade, and cisternal blood volume. Conclusions Onset TCA is not a rare event as it complicates 11% of cases of SAH. New and clinically relevant findings are the association of onset TCA with in-hospital seizures, pneumonia and delayed cerebral ischemia. Despite the increased risk of in-hospital complications, onset TCA is not associated with disability, mortality, and epilepsy at 3 months.

Impact of premorbid hypertension on haemorrhage severity and aneurysm rebleeding risk after subarachnoid haemorrhage

Objective Arterial hypertension (HTN) is a risk factor for subarachnoid haemorrhage (SAH). We aimed to assess the impact of premorbid HTN on the severity of initial bleeding and the risk of aneurysm rebleeding after SAH. Design Retrospective analysis of a prospective cohort study of all SAH patients admitted to Columbia University Medical Center between 1996 and 2012. Results We enrolled 1312 consecutive patients with SAH; 643 (49%) had premorbid HTN. Patients with premorbid HTN presented more frequently as Hunt–Hess Grade IV or V (36% vs 25%, p<0.001) and World Federation of Neurosurgical Societies (WFNS) Grade 4 or 5 (42.6% vs 28.2%, p<0.001), with larger amounts of subarachnoid (Hijdra Sum Score 17 vs 14, p<0.001) and intraventricular blood (median IVH sum score 2 vs 1, p<0.001), and more often with intracerebral haemorrhage (20% vs 13%, p=0.002). In multivariate analysis, patients with premorbid HTN had a higher risk of in-hospital aneurysm rebleeding (11.8% vs 5.5%, adjusted OR 1.67, 95% CI 1.02 to 2.74, p=0.04) after adjusting for age, admission, Hunt–Hess grade, size and site of the ruptured aneurysm. Conclusions Premorbid HTN is associated with increased severity of the initial bleeding event and represents a significant risk factor for aneurysm rebleeding. Given that aneurysm rebleeding is a potentially fatal—but preventable—complication, these findings are of clinical relevance.

Nutritional support and brain tissue glucose metabolism in poor-grade SAH: a retrospective observational study

IntroductionWe sought to determine the effect of nutritional support and insulin infusion therapy on serum and brain glucose levels and cerebral metabolic crisis after aneurysmal subarachnoid hemorrhage (SAH).MethodsWe used a retrospective observational cohort study of 50 mechanically ventilated poor-grade (Hunt-Hess 4 or 5) aneurysmal SAH patients who underwent brain microdialysis monitoring for an average of 109 hours. Enteral nutrition was started within 72 hours of admission whenever feasible. Intensive insulin therapy was used to maintain serum glucose levels between 5.5 and 7.8 mmol/l. Serum glucose, insulin and caloric intake from enteral tube feeds, dextrose and propofol were recorded hourly. Cerebral metabolic distress was defined as a lactate to pyruvate ratio (LPR) > 40. Time-series data were analyzed using a general linear model extended by generalized estimation equations (GEE).ResultsDaily mean caloric intake received was 13.8 ± 6.9 cal/kg and mean serum glucose was 7.9 ± 1 mmol/l. A total of 32% of hourly recordings indicated a state of metabolic distress and < 1% indicated a state of critical brain hypoglycemia (< 0.2 mmol/l). Calories received from enteral tube feeds were associated with higher serum glucose concentrations (Wald = 6.07, P = 0.048), more insulin administered (Wald = 108, P < 0.001), higher body mass index (Wald = 213.47, P < 0.001), and lower body temperature (Wald = 4.1, P = 0.043). Enteral feeding (Wald = 1.743, P = 0.418) was not related to brain glucose concentrations after accounting for serum glucose concentrations (Wald = 67.41, P < 0.001). In the presence of metabolic distress, increased insulin administration was associated with a relative reduction of interstitial brain glucose concentrations (Wald = 8.26, P = 0.017), independent of serum glucose levels.ConclusionsIn the presence of metabolic distress, insulin administration is associated with reductions in brain glucose concentration that are independent of serum glucose levels. Further study is needed to understand how nutritional support and insulin administration can be optimized to minimize secondary injury after subarachnoid hemorrhage.

Cerebral microbleeds in patients with acute subarachnoid hemorrhage.

BACKGROUND Cerebral microbleeds (CMBs) are commonly found after stroke but have not previously been studied in patients with subarachnoid hemorrhage (SAH). OBJECTIVE To study the prevalence, radiographic patterns, predictors, and impact on outcome of CMBs in patients with SAH. METHODS We analyzed retrospectively 39 consecutive patients who underwent T2*-weighted gradient-echo imaging within 7 days after onset of spontaneous SAH. We report the frequency and location of CMBs and show their association with demographics, vascular risk factors, the Hunt-Hess grade, the modified Fisher Scale, the Acute Physiological and Chronic Health Evaluation II, magnetic resonance imaging findings including diffusion-weighted imaging lesions, and laboratory data, as well as data on rebleeding, global cerebral edema, delayed cerebral ischemia, seizures, the Telephone Interview for Cognitive Status, and the modified Rankin Scale. RESULTS Eighteen patients (46%) had CMBs. Of these patients, 9 had multiple CMBs, and overall a total of 50 CMBs were identified. The most common locations of CMBs were lobar (n = 23), followed by deep (n = 15) and infratentorial (n = 12). After adjustment for age and history of hypertension, CMBs were related to the presence of diffusion-weighted imaging lesions (odds ratio, 5.24; 95% confidence interval, 1.14-24.00; P = .03). Three months after SAH, patients with CMBs had nonsignificantly higher modified Rankin Scale scores (odds ratio, 2.50; 95% confidence interval, 0.67-9.39; P = .18). CONCLUSION This study suggests that CMBs are commonly observed and associated with diffusion-weighted imaging lesions in patients with SAH. Our findings may represent a new mechanism of tissue injury in SAH. Further studies are needed to investigate the clinical implications of CMBs.

The SAFARI Score to Assess the Risk of Convulsive Seizure During Admission for Aneurysmal Subarachnoid Hemorrhage

BACKGROUND Seizure is a significant complication in patients under acute admission for aneurysmal SAH and could result in poor outcomes. Treatment strategies to optimize management will benefit from methods to better identify at‐risk patients. OBJECTIVE To develop and validate a risk score for convulsive seizure during acute admission for SAH. METHODS A risk score was developed in 1500 patients from a single tertiary hospital and externally validated in 852 patients. Candidate predictors were identified by systematic review of the literature and were included in a backward stepwise logistic regression model with in‐hospital seizure as a dependent variable. The risk score was assessed for discrimination using the area under the receiver operator characteristics curve (AUC) and for calibration using a goodness‐of‐fit test. RESULTS The SAFARI score, based on 4 items (age ≥ 60 yr, seizure occurrence before hospitalization, ruptured aneurysm in the anterior circulation, and hydrocephalus requiring cerebrospinal fluid diversion) had AUC = 0.77, 95% confidence interval (CI): 0.73‐0.82 in the development cohort. The validation cohort had AUC = 0.65, 95% CI 0.56‐0.73. A calibrated increase in the risk of seizure was noted with increasing SAFARI score points. CONCLUSION The SAFARI score is a simple tool that adequately stratified SAH patients according to their risk for seizure using a few readily derived predictor items. It may contribute to a more individualized management of seizure following SAH.