Christopher Commichau

Cardiac Troponin Elevation, Cardiovascular Morbidity, and Outcome After Subarachnoid Hemorrhage

Background— Cardiac troponin I (cTI) release occurs frequently after subarachnoid hemorrhage (SAH) and has been associated with a neurogenic form of myocardial injury. The prognostic significance and clinical impact of these elevations remain poorly defined. Methods and Results— We studied 253 SAH patients who underwent serial cTI measurements for clinical or ECG signs of potential cardiac injury. These patients were drawn from an inception cohort of 441 subjects enrolled in the Columbia University SAH Outcomes Project between November 1998 and August 2002. Peak cTI levels were divided into quartiles or classified as undetectable. Adverse in-hospital events were prospectively recorded, and outcome at 3 months was assessed with the modified Rankin Scale. Admission predictors of cTI elevation included poor clinical grade, intraventricular hemorrhage, loss of consciousness at ictus, global cerebral edema, and a composite score of physiological derangement (all P≤0.01). Peak cTI level was associated with an increased risk of echocardiographic left ventricular dysfunction (odds ratio [OR], 1.3 per quintile; 95% CI, 1.0 to 1.7; P=0.03), pulmonary edema (OR, 2.1 per quintile; 95% CI, 1.6 to 2.7; P<0.001), hypotension requiring pressors (OR, 1.9 per quintile; 95% CI, 1.5 to 2.3; P<0.001), and delayed cerebral ischemia from vasospasm (OR, 1.3 per quintile; 95% CI, 1.07 to 1.7; P=0.01). Peak cTI levels were predictive of death or severe disability at discharge after controlling for age, clinical grade, and aneurysm size (adjusted OR, 1.4 per quintile; 95% CI, 1.1 to 1.9; P=0.02), but this association was no longer significant at 3 months. Conclusions— cTI elevation after SAH is associated with an increased risk of cardiopulmonary complications, delayed cerebral ischemia, and death or poor functional outcome at discharge.

Phenytoin Exposure Is Associated With Functional and Cognitive Disability After Subarachnoid Hemorrhage

Background and Purpose— Phenytoin (PHT) is routinely used for seizure prophylaxis after subarachnoid hemorrhage (SAH), but may adversely affect neurologic and cognitive recovery. Methods— We studied 527 SAH patients and calculated a “PHT burden” for each by multiplying the average serum level of PHT by the time in days between the first and last measurements, up to a maximum of 14 days from ictus. Functional outcome at 14 days and 3 months was measured with the modified Rankin scale, with poor functional outcome defined as dependence or worse (modified Rankin Scale ≥4). We assessed cognitive outcomes at 14 days and 3 months with the telephone interview for cognitive status. Results— PHT burden was associated with poor functional outcome at 14 days (OR, 1.5 per quartile; 95% CI, 1.3 to 1.8; P<0.001), although not at 3 months (P=0.09); the effect remained (OR, 1.6 per quartile; 95% CI, 1.2 to 2.1; P<0.001) after correction for admission Glasgow Coma Scale, fever, stroke, age, National Institutes of Health Stroke Scale ≥10, hydrocephalus, clinical vasospasm, and aneurysm rebleeding. Seizure in hospital (OR, 4.1; 95% CI, 1.5 to 11.1; P=0.002) was associated with functional disability in a univariate model only. Higher quartiles of PHT burden were associated with worse telephone interview for cognitive status scores at hospital discharge (P<0.001) and at 3 months (P=0.003). Conclusions— Among patients treated with PHT, burden of exposure to PHT predicts poor neurologic and cognitive outcome after SAH.

Clinical trial of a novel surface cooling system for fever control in neurocritical care patients

Objective:To compare the efficacy of a novel water-circulating surface cooling system with conventional measures for treating fever in neuro-intensive care unit patients. Design:Prospective, unblinded, randomized controlled trial. Setting:Neurologic intensive care unit in an urban teaching hospital. Patients:Forty-seven patients, the majority of whom were mechanically ventilated and sedated, with fever ≥38.3°C for >2 consecutive hours after receiving 650 mg of acetaminophen. Interventions:Subjects were randomly assigned to 24 hrs of treatment with a conventional water-circulating cooling blanket placed over the patient (Cincinnati SubZero, Cincinnati OH) or the Arctic Sun Temperature Management System (Medivance, Louisville CO), which employs hydrogel-coated water-circulating energy transfer pads applied directly to the trunk and thighs. Measurements and Main Results:Diagnoses included subarachnoid hemorrhage (60%), cerebral infarction (23%), intracerebral hemorrhage (11%), and traumatic brain injury (4%). The groups were matched in terms of baseline variables, although mean temperature was slightly higher at baseline in the Arctic Sun group (38.8 vs. 38.3°C, p = .046). Compared with patients treated with the SubZero blanket (n = 24), Arctic Sun-treated patients (n = 23) experienced a 75% reduction in fever burden (median 4.1 vs. 16.1 C°-hrs, p = .001). Arctic Sun-treated patients also spent less percent time febrile (T ≥38.3°C, 8% vs. 42%, p < .001), spent more percent time normothermic (T ≤37.2°C, 59% vs. 3%, p < .001), and attained normothermia faster than the SubZero group median (2.4 vs. 8.9 hrs, p = .008). Shivering occurred more frequently in the Arctic Sun group (39% vs. 8%, p = .013). Conclusion:The Arctic Sun Temperature Management System is superior to conventional cooling-blanket therapy for controlling fever in critically ill neurologic patients.

Risk factors for fever in the neurologic intensive care unit

Objective: To identify risk factors for fever among patients treated in a neurologic intensive care unit (NICU). Methods: The authors prospectively studied the frequency and causes of fever, defined as a patient’s first temperature ≥101 °F (38.3 °C), among 387 patients consecutively admitted to their NICU. After identifying risk factors for 1) any fever, 2) infectious fever, and 3) unexplained fever using logistic regression, they calculated disease-specific adjusted odds ratios for developing these types of fever among 12 diagnostic groups. Results: Fever occurred in 23% (87/387) of patients. Fifty-two percent of fevers were explained by infection (predominantly pneumonia or bronchitis), and 28% were unexplained despite a complete diagnostic evaluation. NICU length of stay was a risk factor for all three types of fever (all p < 0.004); other risk factors included depressed level of consciousness for any fever (p = 0.005) and infectious fever (p = 0.048), endotracheal intubation for infectious fever (p = 0.01), and intraventricular catheterization for unexplained fever (p = 0.004). Subarachnoid hemorrhage increased the risk of both infectious and unexplained fever, even after adjusting for these risk factors (p = 0.006). Conclusion: Fever occurs in nearly 25% of NICU patients, and is associated with increased length of stay and depressed level of consciousness. Endotracheal intubation is a risk factor for infectious fever, whereas intraventricular catheterization is a risk factor for unexplained fever, which suggests a role for ventricular hemorrhage in the pathogenesis of “central” fever. Subarachnoid hemorrhage increases the risk of developing fever of all types.

Higher hemoglobin is associated with improved outcome after subarachnoid hemorrhage

Objective:There are few data regarding anemia and transfusion after subarachnoid hemorrhage (SAH). We addressed the hypothesis that higher hemoglobin (HGB) levels are associated with less death and disability after SAH. Design:Prospective registry with automated data retrieval. Patients:Six hundred eleven patients enrolled in the Columbia University SAH Outcomes Project between August 1996 and June 2002. Setting:Neurologic intensive care unit. Interventions:Patients were treated according to standard management protocols. Measurements and Main Results:We electronically retrieved all HGB readings during the acute hospital stay for 611 consecutively admitted SAH patients. Outcomes were measured with the modified Rankin Scale at 14 days or discharge, and at 3 months. Patients who were independent (modified Rankin Scale, 0–3) at discharge or 14 days had higher mean (11.7 ± 1.5 vs. 10.9 ± 1.2, p < .001) and nadir (9.9 ± 2.1 vs. 8.6 ± 1.8, p < .001) HGB, and had higher HGB values every day in the hospital. There were similar results when patients were stratified by mortality. Higher HGB was associated with reduced risk of poor outcome (modified Rankin Scale, 4–6) at 14 days/discharge and 3 months after correcting for Hunt and Hess grade, age, history of diabetes, and cerebral infarction. Length of stay and HGB interacted such that lower HGB has a more pronounced effect with length of stay > 14 days. Conclusions:Higher HGB values are associated with improved outcomes after SAH at 14 days/discharge and 3 months. In contrast to general critical care patients, SAH patients may benefit from higher HGB. Determination of the optimal goal HGB after SAH will require separate prospective research.

Effect of prior statin use on functional outcome and delayed vasospasm after acute aneurysmal subarachnoid hemorrhage: a matched controlled cohort study.

OBJECTIVE:Hydroxymethylglutaryl coenzyme A reductase inhibitors (statins), which exhibit beneficial cerebrovascular effects by modulating inflammation and nitric oxide production, have not been evaluated in acute aneurysmal subarachnoid hemorrhage (SAH) patients. The effect of prior statin use on 14-day functional outcome and on prevention of vasospasm-induced delayed cerebral ischemia (DCI) or stroke during hospitalization was analyzed. METHODS:We conducted a 1:2 matched (age, admission Hunt and Hess grade, vascular disease/risk history) cohort study of 20 SAH patients on statins and 40 SAH controls. The primary outcome was functional outcome at 14 days (Modified Lawton Physical Self-Maintenance Scale and Barthel Index scale scores). Secondary outcomes were 14-day mortality, Modified Rankin Scale score, DCI, DCI supported by angiography/transcranial Doppler [TCD], cerebral infarctions of any type, and TCD highest mean velocity elevation. RESULTS:Statin users demonstrated a significant protective effect on 14-day Barthel Index scale and Modified Lawton Physical Self-Maintenance Scale scores (77 ± 10 versus 39 ± 8, P = 0.003; 12 ± 7 versus 19 ± 9, P = 0.03, respectively). Moreover, statin users demonstrated a significantly lower incidence of DCI and DCI supported by angiography/TCD (10% versus 43%, P = 0.02; 5% versus 35%, P = 0.01, respectively), cerebral infarctions of any type (25% versus 63%, P = 0.01), and baseline-to-final TCD highest mean velocity change of 50 cm/s or greater (18% versus 51%, P = 0.03). CONCLUSION:SAH statin users demonstrated significant improvement in 14-day functional outcome, a significantly lower incidence of DCI and cerebral infarctions of any type, as well as prevention of TCD highest mean velocity elevation. However, we did not find a significant statin impact on mortality or global outcome (Modified Rankin Scale) in this small sample. This study provides clinical evidence for the potential therapeutic benefit of statins after acute SAH.

Clinical trial of an air-circulating cooling blanket for fever control in critically ill neurologic patients

Objective: To evaluate the efficacy of an air-circulating cooling blanket for reducing body temperature in febrile neuro-ICU patients treated with acetaminophen. Methods: Two-hundred twenty consecutively admitted neuro-ICU patients whose tympanic membrane temperature reached or exceeded 101 °F (38.3 °C) were randomly assigned to receive acetaminophen (650 mg every 4 hours) alone (n = 107) or acetaminophen plus air blanket therapy (n = 113). After 24 hours of treatment, the authors compared the proportion of subjects who attained treatment success (T ≤ 99 °F) or treatment failure (T ≥ 101 °F for 2 consecutive hours) using the χ2 test and the time to reach these endpoints using Kaplan-Meier survival analysis. Main Results: Air blanket therapy resulted in a small increase in the proportion of subjects with treatment success (44% versus 36%, χ2 p = 0.19, log rank p = 0.10) and a similar small reduction in the proportion of patients with treatment failure (42% versus 53%, χ2 p = 0.11, log-rank p = 0.21), compared with treatment with acetaminophen alone. Approximately one third of patients in both groups remained febrile after randomization and “failed” after the first 2 hours of treatment. Twelve percent of patients assigned to air blanket therapy refused or were unable to tolerate treatment, compared with 2% of patients treated with acetaminophen alone (p = 0.005). Conclusions: Treatment with an air-circulating cooling blanket did not effectively reduce body temperature in febrile neuro-ICU patients treated with acetaminophen. More effective interventions are needed to maintain normothermia in patients at risk for fever-related brain damage.

Dobutamine versus milrinone after subarachnoid hemorrhage.

OBJECTIVE:Neurogenic stunned myocardium is a well-recognized complication of subarachnoid hemorrhage. Dobutamine and milrinone are both used for neurogenic stunned myocardium, but there are few data comparing them after subarachnoid hemorrhage. METHODS:We compared the physiological dose response of dobutamine and milrinone in patients with subarachnoid hemorrhage requiring a pulmonary artery catheter. We located 11 patients who received either inotrope. Physiological data were fitted to a mixed model accounting for drug, dose, and between-patient variation. RESULTS:There were 11 patients who had 152 pulmonary artery catheter measurements. Two received both inotropes (but not within 4 h of each other), 2 only milrinone, and 7 only dobutamine. The groups had similar clinical and physiological characteristics. After adjustment for vasopressin, milrinone was significantly more potent in increasing cardiac output (P < 0.0001) and stroke volume (P = 0.03), while decreasing vascular resistance (P < 0.0001) and systolic blood pressure (P = 0.008), than dobutamine. CONCLUSION:These data suggest that milrinone and dobutamine should be used in different clinical situations. Milrinone may be more effective in patients with severely depressed systolic function but who have at least normal vascular resistance and blood pressure and in whom raising cardiac output is the primary goal. Dobutamine may be superior when vascular resistance or blood pressure is low.

Spine Disorders: Medical and Surgical Management

The authors of this work set out to produce a text that is clinically oriented, focusing on the evaluation and management of spine disorders that are frequently seen by primary practitioners. This project stems from a popular course given for many years at the annual American Academy of Neurology meetings. It is a text with clear organization covering basic anatomy and pathophysiology; the authors then focus on each region of the spine (cervical, thoracic, and lumbar). The chapters that follow cover the specifics of diagnostic testing, imaging, and indications for surgical referral, as well as the basics of surgical intervention. There is a clear focus on mechanical disorders, and expanding on vascular, inflammatory, and neoplastic conditions should be considered for future editions. This is not so much a weakness because this is not meant to be a subspecialty text. The final appendix is a very nice inventory of clinical pearls drawn from the years of clinical experience shared by the authors.

Critical care of subarachnoid and intracerebral hemorrhage

Intensive care plays an important role in the management of subarachnoid and intracerebral hemorrhage. Aggressive intensive care unit-based management protocols for stuporous or comatose patients with subarachnoid hemorrhage, including early aneurysm obliteration and hemodynamic augmentation to treat ischemia from vasospasm, have been shown to increase survival dramatically. Endovascular occlusion of acutely ruptured aneurysms has been shown to prevent early rebleeding and is a promising option for patients who cannot undergo early surgical clipping due to the complexity of their aneurysm or medical comorbidity. Early neurologic deterioration in patients with hypertensive intracerebral hemorrhage has been shown to result from progressive hematoma expansion, which occurs in 30% of patients presenting within 3 hours of onset. Studies of the effects of standard critical care interventions such as blood pressure reduction on early intracerebral hemorrhage growth are needed.