Noeleen Ostapkovich

Impact of medical complications on outcome after subarachnoid hemorrhage.

Objective:Medical complications occur frequently after subarachnoid hemorrhage (SAH). Their impact on outcome remains poorly defined. Design:Inception cohort study. Patients:Five-hundred eighty patients enrolled in the Columbia University SAH Outcomes Project between July 1996 and May 2002. Setting:Neurologic intensive care unit. Interventions:Patients were treated according to standard management protocols. Measurements and Main Results:Poor outcome was defined as death or severe disability (modified Rankin score, 4–6) at 3 months. We calculated the frequency of medical complications according to prespecified criteria and evaluated their impact on outcome, using forward stepwise multiple logistic regression after adjusting for known predictors of poor outcome. Thirty-eight% had a poor outcome; mortality was 21%. The most frequent complications were temperature >38.3°C (54%), followed by anemia treated with transfusion (36%), hyperglycemia >11.1 mmol/L (30%), treated hypertension (>160 mm Hg systolic; 27%), hypernatremia >150 mmol/L (22%), pneumonia (20%), hypotension (<90 mm Hg systolic) treated with vasopressors (18%), pulmonary edema (14%), and hyponatremia <130 mmol/L (14%). Fever (odds ratio [OR], 2.0; 95% confidence interval [CI], 1.1–3.4; p = .02), anemia (OR, 1.8; 95% CI, 1.1–2.9; p = .02), and hyperglycemia (OR, 1.8; 95% CI, 1.1–3.0; p = .02) significantly predicted poor outcome after adjustment for age, Hunt-Hess grade, aneurysm size, rebleeding, and cerebral infarction due to vasospasm. Conclusions:Fever, anemia, and hyperglycemia affect 30% to 54% of patients with SAH and are significantly associated with mortality and poor functional outcome. Critical care strategies directed at maintaining normothermia, normoglycemia, and prevention of anemia may improve outcome after SAH. LEARNING OBJECTIVESOn completion of this article, the reader should be able to: Identify common medical complications after subarachnoid hemorrhage. Describe complications that influence outcome. Use this inofrmation in a clinical setting. Dr. Connolly has disclosed that he is/was the recipient of direct grant/research funds from the National Institutes of Health. The remaining authors have disclosed that they have no financial relationships with or interests in any commercial companies pertaining to the educational activity. Wolters Kluwer has identified and resolved all faculty conflicts of interest regarding the educational activity. Visit the Critical Care Medicine Web site (www.ccmjournal.org) for information on obtaining continuing medical education credit.

Impact of tight glycemic control on cerebral glucose metabolism after severe brain injury: A microdialysis study*

Objectives:To analyze the effect of tight glycemic control with the use of intensive insulin therapy on cerebral glucose metabolism in patients with severe brain injury. Design:Retrospective analysis of a prospective observational cohort. Setting:University hospital neurologic intensive care unit. Patients:Twenty patients (median age 59 yrs) monitored with cerebral microdialysis as part of their clinical care. Interventions:Intensive insulin therapy (systemic glucose target: 4.4–6.7 mmol/L [80–120 mg/dL]). Measurements and Main Results:Brain tissue markers of glucose metabolism (cerebral microdialysis glucose and lactate/pyruvate ratio) and systemic glucose were collected hourly. Systemic glucose levels were categorized as within the target “tight” (4.4–6.7 mmol/L [80–120 mg/dL]) vs. “intermediate” (6.8–10.0 mmol/L [121–180 mg/dL]) range. Brain energy crisis was defined as a cerebral microdialysis glucose <0.7 mmol/L with a lactate/pyruvate ratio >40. We analyzed 2131 cerebral microdialysis samples: tight systemic glucose levels were associated with a greater prevalence of low cerebral microdialysis glucose (65% vs. 36%, p < 0.01) and brain energy crisis (25% vs.17%, p < 0.01) than intermediate levels. Using multivariable analysis, and adjusting for intracranial pressure and cerebral perfusion pressure, systemic glucose concentration (adjusted odds ratio 1.23, 95% confidence interval [CI] 1.10–1.37, for each 1 mmol/L decrease, p < 0.001) and insulin dose (adjusted odds ratio 1.10, 95% CI 1.04–1.17, for each 1 U/hr increase, p = 0.02) independently predicted brain energy crisis. Cerebral microdialysis glucose was lower in nonsurvivors than in survivors (0.46 ± 0.23 vs. 1.04 ± 0.56 mmol/L, p < 0.05). Brain energy crisis was associated with increased mortality at hospital discharge (adjusted odds ratio 7.36, 95% CI 1.37–39.51, p = 0.02). Conclusions:In patients with severe brain injury, tight systemic glucose control is associated with reduced cerebral extracellular glucose availability and increased prevalence of brain energy crisis, which in turn correlates with increased mortality. Intensive insulin therapy may impair cerebral glucose metabolism after severe brain injury.

Do Standard Monitoring Sites Reflect True Brain Temperature When Profound Hypothermia Is Rapidly Induced and Reversed

Background Brain temperature is closely approximated by most body temperature measurements under normal anesthetic conditions. However, when thermal autoregulation is overridden, large temperature gradients may prevail. This study sought to determine which of the standard temperature monitoring sites best approximates brain temperature when deep hypothermia is rapidly induced and reversed during cardiopulmonary bypass. Methods Twenty-seven patients underwent cardiopulmonary bypass and deep hypothermic circulatory arrest in order for each to have a giant cerebral aneurysm surgically clipped. Brain temperatures were measured directly with a thermocouple embedded in the cerebral cortex. Eight other body temperatures were monitored simultaneously with less invasive sensors at standard sites. Results Brain temperature decreased from 32.6 + 1.4 degrees Celsius (mean plus/minus SD) to 16.7 plus/minus 1.7 degrees Celsius in 28 plus/minus 7 min, for an average cerebral cooling rate of 0.59 + 0.15 degree Celsius/min. Circulatory arrest lasted 24 plus/minus 15 min and was followed by 63 + 17 min of rewarming at 0.31 plus/minus 0.09 degree Celsius/min. None of the monitored sites tracked cerebral temperature well throughout the entire hypothermic period. During rapid temperature change, nasopharyngeal, esophageal, and pulmonary artery temperatures corresponded to brain temperature with smaller mean differences than did those of the tympanic membrane, bladder, rectum, axilla, and sole of the foot. At circulatory arrest, nasopharyngeal, esophageal, and pulmonary artery mean temperatures were within 1 degree Celsius of brain temperature, even though individual patients frequently exhibited disparate values at those sites. Conclusions When profound hypothermia is rapidly induced and reversed, temperature measurements made at standard monitoring sites may not reflect cerebral temperature. Measurements from the nasopharynx, esophagus, and pulmonary artery tend to match brain temperature best but only with an array of data can one feel comfortable disregarding discordant readings.

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.

Comparison of Remifentanil and Fentanyl in Patients Undergoing Craniotomy for Supratentorial Space-occupying Lesions

BackgroundRemifentanil hydrochloride is an ultra-short-acting, esterase-metabolized micro-opioid receptor agonist. This study compared the use of remifentanil or fentanyl during elective supratentorial craniotomy for space-occupying lesions.MethodsSixty-three adults gave written informed consent for

Fever after subarachnoid hemorrhage. Risk factors and impact on outcome

Objective: To identify risk factors for refractory fever after subarachnoid hemorrhage (SAH), and to determine the impact of temperature elevation on outcome. Methods: We studied a consecutive cohort of 353 patients with SAH with a maximum daily temperature (Tmax) recorded on at least 7 days between SAH days 0 and 10. Fever (>38.3 °C) was routinely treated with acetaminophen and conventional water-circulating cooling blankets. We calculated daily Tmax above 37.0 °C, and defined extreme Tmax as daily excess above 38.3 °C. Global outcome at 90 days was evaluated with the modified Rankin Scale (mRS), instrumental activities of daily living (IADLs) with the Lawton scale, and cognitive functioning with the Telephone Interview of Cognitive Status. Mixed-effects models were used to identify predictors of Tmax, and logistic regression models to evaluate the impact of Tmax on outcome. Results: Average daily Tmax was 1.15 °C (range 0.04 to 2.74 °C). The strongest predictors of fever were poor Hunt-Hess grade and intraventricular hemorrhage (IVH) (both p < 0.001). After controlling for baseline outcome predictors, daily Tmax was associated with an increased risk of death or severe disability (mRS ≥ 4, adjusted OR 3.0 per °C, 95% CI 1.6 to 5.8), loss of independence in IADLs (OR 2.6, 95% CI 1.2 to 5.6), and cognitive impairment (OR 2.5, 95% CI 1.2 to 5.1, all p ≤ 0.02). These associations were even stronger when extreme Tmax was analyzed. Conclusion: Treatment-refractory fever during the first 10 days after subarachnoid hemorrhage (SAH) is predicted by poor clinical grade and intraventricular hemorrhage, and is associated with increased mortality and more functional disability and cognitive impairment among survivors. Clinical trials are needed to evaluate the impact of prophylactic fever control on outcome after SAH.

Metabolic Impact of Shivering During Therapeutic Temperature Modulation The Bedside Shivering Assessment Scale

Background and Purpose— Therapeutic temperature modulation is widely used in neurocritical care but commonly causes shivering, which can hamper the cooling process and result in increases in systemic metabolism. We sought to validate a grading scale to assist in the monitoring and control of shivering. Methods— A simple 4-point Bedside Shivering Assessment Scale was validated against continuous assessments of resting energy expenditure, oxygen consumption, and carbon dioxide production as measured by indirect calorimetry. Therapeutic temperature modulation for fever control or the induction of hypothermia was achieved with the use of a surface or endovascular device. Expected energy expenditure was calculated using the Harris–Benedict equation. A hypermetabolic index was calculated from the ratio of resting of energy expenditure to energy expenditure. Results— Fifty consecutive cerebrovascular patients underwent indirect calorimetry between January 2006 and June 2007. Fifty-six percent were women, and mean age 63±16 years. The majority underwent fever control (n=40 [80%]) with a surface cooling device (n=44 [87%]) and had signs of shivering (Bedside Shivering Assessment Scale >0, 64% [n=34 of 50]). Low serum magnesium was independently associated with the presence of shivering (Bedside Shivering Assessment Scale >0; OR, 6.8; 95% CI, 1.7 to 28.0; P=0.01). The Bedside Shivering Assessment Scale was independently associated with the hypermetabolic index (W=16.3, P<0.001), oxygen consumption (W=26.3, P<0.001), resting energy expenditure (W=27.2, P<0.001), and carbon dioxide production (W=18.2, P<0.001) with a high level of interobserver reliability (&kgr;w=0.84, 95% CI, 0.81 to 0.86). Conclusion— The Bedside Shivering Assessment Scale is a simple and reliable tool for evaluating the metabolic stress of shivering.

Hyperglycemia After SAH: Predictors, Associated Complications, and Impact on Outcome

Background and Purpose— Hyperglycemia is common after subarachnoid hemorrhage (SAH). The extent to which prolonged hyperglycemia contributes to in-hospital complications and poor outcome after SAH is unknown. Methods— We studied an inception cohort of 281 SAH patients with an initial serum glucose level obtained within 3 days of SAH onset and who had at least 7 daily glucose measurements between SAH days 0 and 10. We defined mean glucose burden (GB) as the average peak daily glucose level >5.8 mmol/L (105 mg/dL). Hospital complications were recorded prospectively, and 3-month outcome was assessed with the modified Rankin scale. Results— The median GB was 1.8 mmol/L (33 mg/dL). Predictors of high-GB included age ≥54 years, Hunt and Hess grade III–V, poor Acute Physiology and Chronic Health Evaluation (APACHE)-2 physiological subscores, and a history of diabetes mellitus (all P≤0.001). In a multivariate analysis, GB was associated with increased intensive care unit length of stay (P=0.003) and the following complications: congestive heart failure, respiratory failure, pneumonia, and brain stem compression from herniation (all P<0.05). After adjusting for Hunt-Hess grade, aneurysm size, and age, GB was an independent predictor of death (odds ratio, 1.10 per mmol/L; 95% CI, 1.01 to 1.21; P=0.027) and death or severe disability (modified Rankin scale score of 4 to 6; odds ratio, 1.17 per mmol/L; 95% CI 1.07 to 1.28, P<0.001). Conclusions— Hyperglycemia after SAH is associated with serious hospital complications, increased intensive care unit length of stay, and an increased risk of death or severe disability.

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.