Mild hypothermia: an alternative to deep hypothermia for achieving neuroprotection.

The role of excitotoxins in the ischemic cascade that results in ischemic neuronal death has been clearly defined and has brought about attempts to halt the progression of neurologic damage. Improved understanding of this process has allowed for the development of interventions to optimize neurologic outcome following periods of ischemia. Deep hypothermia (15-22 degrees C) has long been recognized as one method of achieving neuroprotection, but is not without serious implications and risks to the patient. Mild hypothermia (32-34 degrees C) is evolving as an alternative neuroprotective measure that has been shown to improve neurologic outcome in experimental models of ischemia and head injury, as well as in recent head injury clinical trials. It has been safely used intraoperatively in a large series of patients undergoing craniotomy. Mild hypothermia is a technique that may soon be commonly employed alone or in conjunction with other methods of neuroprotection. Nurses caring for patients undergoing this technique must be aware of the practice implications associated with this procedure and adapt their care accordingly.

Cigarette smoking as a cause of aneurysmal subarachnoid hemorrhage and risk for vasospasm: a report of the Cooperative Aneurysm Study.

OBJECT: Cigarette smoking is associated with aneurysmal subarachnoid hemorrhage (SAH) and subsequent vasospasm. The purpose of this study was to quantify this association. METHODS: Nearly 3500 patients with SAH from North America and Europe have been enrolled in five different multicenter, controlled studies coordinated at the Neuroclinical Trials Center of the Virginia Neurological Institute at the University of Virginia. Among the prospective data gathered were whether the patient smoked at the time of their most recent SAH and the evolution of angiographic vasospasm. The rate of smoking in the patients enrolled in the studies was compared with the expected rate by using a chi-square statistic adjusted for age and gender, in the general population in the United States (U.S.) and Europe. In virtually all age and gender subgroups, and for the combined populations in the five clinical trials, patients with SAH reported current smoking rates 2.5 times higher than expected based on U.S. and European national surveys (p < 0.0001). Cigarette smoking was also associated with younger age at onset of SAH (5-10 years, p < 0.0001) and increased incidence of clinically confirmed vasospasm (p < 0.005). CONCLUSIONS: The findings of a significantly increased representation of current cigarette smokers in the study populations and significant association with younger age at the time of SAH and increased incidence of vasospasm concur with recent reports of smoking as a significant risk factor for ruptured aneurysms and subsequent vasospasm.

Risk classification after aneurysmal subarachnoid hemorrhage.

BACKGROUND: Prediction of patient outcome is an important aspect of the management and study of aneurysmal subarachnoid hemorrhage (SAH). In the present study, we evaluated the prognostic value of two multivariate approaches to risk classification, Classification and Regression Trees (CART) and multiple logistic regression, and compared them with the best single predictor of outcome, level of consciousness. METHODS: Data prospectively collected in the first Cooperative Aneurysm Study of intravenous nicardipine after aneurysmal SAH (NICSAH I, n = 885) were used to develop the prediction models. Low-, medium-, and high-risk groups for unfavorable outcome were devised using CART and a stepwise logistic regression analysis. Admission factors incorporated into both classification schemes were: level of consciousness, age, location of aneurysm (basilar versus other), and the Glasgow Coma Score. The CART prediction tree also branched on a dichotomy of admission glucose level. The two multivariate classifications were then compared with a prediction scheme based on the single best performing prognostic factor, level of consciousness in an independent series, NICSAH II (n = 353), and also in the original training dataset. RESULTS: A similar discrimination of risk was achieved by the three classification systems in the testing sample (NICSAH II). The 8%, 19%, and 52% rates of unfavorable outcome obtained from low-, medium-, and high-risk groups defined by LOC approximated those obtained using the more complex multivariate systems. CONCLUSION: Although multivariate classification systems are useful to characterize the relationship of multiple risk factors to outcome, the simple clinical measure LOC is favored as a concise and practical classification for predicting the probability of unfavorable outcome after aneurysmal SAH.

Long-term outcome after surgical excision of parenchymal arteriovenous malformations in patients over 60 years of age.

BACKGROUND: Age is considered an important limiting factor for surgical excision of parenchymal arteriovenous malformations (AVMs) and a more conservative therapeutic approach has been advocated in the elderly. There are no studies available investigating the long-term outcome after surgical excision of parenchymal AVMs in patients over 60 years of age. METHODS: We report the surgical outcome after excision of an AVM in a series of 13 consecutive patients older than 60 years. Medical records were analyzed retrospectively. RESULTS: Hemorrhage was the mode of presentation in all patients. Three patients were admitted in a comatose state. Surgery was performed within 1 week from the initial bleeding in seven cases and within 2 weeks in five cases. There were no deaths directly related to surgery in this series. However, one patient died as a result of an intracranial hemorrhage complicating preoperative embolization and another patient died 3 months after surgery from intervening medical complications. During the follow-up period (mean 46 months), three more patients had died 8, 19, and 48 months after surgery, respectively. Of the remaining eight patients, six are doing well and are independent in the activities of daily living. One patient is independent but requires supervision, and the remaining one was lost to follow-up. CONCLUSIONS: Age alone should no longer be considered a contraindication to treatment. In selected cases, surgery can be performed safely even in the elderly patient with an AVM. After surgical excision, elderly patients have the potential for several years of active life.

Overview: hyperacute rt-PA stroke treatment. The NINDS rt-PA Stroke Study Group.

Ischemic stroke remains a significant problem in the United States. Complex intracellular metabolic events occur leading to cell death. A search for treatments to prevent this ischemic process continues. Thrombolytic agents, recently developed and tested, may lessen the disabling effects of stroke.

Pathophysiology and mechanisms of acute ischemic stroke. The NINDS rt-PA Stroke Study Group.

Stroke is a leading cause of death and disability among Americans. The recent US Food and Drug Administration approval of recombinant tissue plasminogen activator (rt-PA, Activase) for the treatment of acute ischemic stroke offers the first proven therapy to reverse or ameliorate stroke symptoms. rt-PA is thought to restore circulation in the patient with acute ischemic stroke by dissolving an occluding thrombus or embolus. A basic understanding of cerebral circulation and the mechanism by which stroke compromises brain tissue is fundamental to appreciating this new therapy. The importance of prompt stroke diagnosis and treatment cannot be underestimated.

Code Stroke: rapid transport, triage and treatment using rt-PA therapy. The NINDS rt-PA Stroke Study Group.

With the approval of rt-PA therapy for ischemic stroke, stroke care has acutely transitioned from focusing on rehabilitative services to emergency services. This treatment, which must be initiated within the first three hours after the onset of stroke symptoms, requires reorganization of current management approaches. Developing a Code Stroke Team facilitates this process and helps to identify potential thrombolysis candidates. A pathway to deliver rapid care begins with 911 notification and transport, emergency department triage and procedures, and moves through the initiation of thrombolytic therapy. We call this pathway "Code Stroke".

Nursing care of acute stroke patients after receiving rt-PA therapy. The NINDS rt-PA Stroke Study Group.

Treatment with tissue plasminogen activator (rt-PA) for acute stroke requires intensive care of the patient. The risk of thrombolytic therapy and the need for rapid interventions make it clear that the nursing role during this time is crucial. Nurses should be familiar with safe dosage and administration of rt-PA for stroke, which is clearly different than administration of rt-PA for myocardial infarction. Furthermore, thrombolytic stroke treatment must be accompanied by intensive neurological monitoring to observe for complications. Intracerebral hemorrhage is usually accompanied by an acute change in neurological status and vital sign instability. Intensive monitoring of neurologic condition, vital signs, cardiac status and other standard critical care practices must be initiated immediately to optimize patient outcome.

Nursing management of acute complications following rt-PA in acute ischemic stroke. The NINDS rt-PA Stroke Study Group.

In the National Institutes of Neurologic Disorders and Stroke (NINDS) recombinant tissue plasminogen activator (rt-PA) stroke trial, the primary adverse events monitored were intracranial hemorrhage (ICH), systemic bleeding, death and new stroke. Nurses caring for the study patients noted these adverse events and other complications. In addition to what is known about acute ischemic stroke (AIS), the NINDS trial provides further information for optimal care of this specific group of patients. The complications found in this trial require expert nursing care to monitor, prevent and intervene, making clinical decisions relevant to the patients needs. The critical decision-making process must be grounded in knowledge of acute stroke physiology and thrombolysis.

Using the NIH Stroke Scale to assess stroke patients. The NINDS rt-PA Stroke Study Group.

The stroke patient is acutely ill within minutes of symptom onset. Typically, he or she is awake and thus requires a focal neurologic exam to evaluate vision, movement, sensation and language. With the advent of acute stroke treatments that need to be rapidly implemented, it is critical that the nurse be able to assess patients and relay the information accurately and efficiently to other members of the health care team. Performing and documenting the awake stroke exam in the most efficient and useful manner is key to the nursing care of the stroke patient. The National Institutes of Health Stroke Scale (NIHSS) is a systematic assessment tool designed to measure the neurologic deficits most often seen with acute stroke patients. Originally designed as a research tool, it is a nonlinear ordinal scale, with possible scores ranging form 0-42. Exam performance has been timed to take 5-8 minutes. Use of the NIHSS includes documentation of neurologic status and outcome, data collection for planning safe nursing care and standardization of information exchanges between nurse caregivers and other health care professionals.

Education to improve stroke awareness and emergent response. The NINDS rt-PA Stroke Study Group.

Patients delay in responding to stroke as an emergency in part because they have deficient information about the disease and treatment. Healthcare providers may also have a lack of information about stroke assessment and management, which could attribute to delays in patient care. In order to provide early, rapid stroke treatment in eligible persons, the public and the healthcare community must be informed. Information on stroke risk, symptoms and treatment should be provided to those likely to experience stroke, the general public and the emergency and medical communities who may witness and intervene when stroke occurs. Programs developed at the eight centers of the National Institute of Neurological Disorders and Stroke (NINDS) rt-PA stroke trial provide a sampling of approaches that increase awareness in these groups. Lessons learned include: 1. Program planning should start with a community needs assessment. 2. A variety of strategies can be applied to meet the community needs and resources. 3. Educational principles and models should be utilized in planning effective programs. 4. The message must be simple: "Stroke is an emergency. Time is brain".

Age and outcome after aneurysmal subarachnoid hemorrhage: why do older patients fare worse?

Advanced age is a recognized prognostic indicator of poor outcome after subarachnoid hemorrhage (SAH). The relationship of age to other prognostic factors and outcome was evaluated using data from the multicenter randomized trial of nicardipine in SAH conducted in 21 neurosurgical centers in North America. Among the 906 patients who were studied, five different age groups were considered: 40 years or less, 41 to 50, 51 to 60, 61 to 70, and more than 71 years. Twenty-three percent of the individuals enrolled were older than 60 years of age. Women outnumbered men in all age groups. Level of consciousness (p = 0.0002) and World Federation of Neurological Surgeons grade (p = 0.0001) at admission worsened with advancing age. Age was also related to the presence of a thick subarachnoid clot (p = 0.0001), intraventricular hemorrhage (p = 0.0003), and hydrocephalus (p = 0.0001) on an admission computerized tomography scan. The rebleeding rate increased from 4.5% in the youngest age group to 16.4% in patients more than 70 years of age (p = 0.002). As expected, preexisting medical conditions, such as diabetes (p = 0.028), hypertension (p = 0.0001), and pulmonary (p = 0.0084), myocardial (p = 0.0001), and cerebrovascular diseases (p = 0.0001), were positively associated with age. There were no age-related differences in the day of admission following SAH, timing of the surgery and/or location, and size (small vs. large) of the ruptured aneurysm. During the treatment period, the incidence of severe complications (that is, those complications considered life threatening by the reporting investigator) increased with advancing age, occurring in 28%, 33%, 36%, 40%, and 46% of the patients in each advancing age group, respectively (p = 0.0002). No differences were observed in the reported frequency of surgical complications. No age-related differences were found in the overall incidence of angiographic vasospasm; however, symptomatic vasospasm was more frequently reported in the older age groups (p = 0.01). Overall outcome, assessed using the Glasgow Outcome Scale at 3 months post-SAH, was poorer with advancing age (p < 0.001). Multivariate analysis of overall outcome, adjusting for the different prognostic factors, did not remove the age effect, which suggests that the aging brain has a less optimal response to the initial bleeding. Age as a risk factor is a continuum; however, there seems to be a significant increased risk of poor outcome after the age of 60 years.

Innovations in aneurysmal subarachnoid hemorrhage: intracisternal t-PA for the prevention of vasospasm.

Aneurysmal subarachnoid hemorrhage (SAH) affects approximately 30,000 people each year in North America. At least 30% of these patients will develop vasospasm as a result of the initial hemorrhage, and two thirds of these develop permanent disabilities or die. Blood deposited into the basal cisterns from the ruptured aneurysm can form thick clots around the major cerebral vessels. The by-products of the hemolyzed clots are believed to be responsible for the subsequent development of vasospasm. Hypervolemic, hypertensive, hemodilution therapy (HHHT) and nimodipine may improve outcome in some cases but there is no therapy known to prevent vasospasm in all patients. One potential therapeutic agent under investigation is tissue plasminogen activator (t-PA), a fibrinolytic enzyme. Instilled into the basal cisterns at time of aneurysm clipping, t-PA dissolves the clot so spasmogenic substances may be removed, thus preventing or reducing the severity of vasospasm.

Gender-related differences in aneurysmal subarachnoid hemorrhage.

Female gender is a recognized risk factor for the occurrence of aneurysmal subarachnoid hemorrhage. In the present study the authors analyzed differences in admission characteristics and outcome between 578 women (64%) and 328 men (36%) who were enrolled in a recently completed clinical trial. The female-to-male ratio was nearly 2:1. The women in the study were older than the men (mean age 51.4 years vs 47.3 years, respectively, p<0.001). Female patients harbored aneurysms of the internal carotid artery more frequently than male patients (36.8% vs. 18.0%, p<0.001) and more often had multiple aneurysms (32.4% vs. 17.6%, p<0.001). On the other hand, anterior cerebral artery aneurysms were more commonly encountered in men (46.1% in men vs. 26.6% in women, p<0.001). Other baseline prognostic factors were balanced between the gender groups. Surgery was performed equally in both sexes (98%), although the time to operation was shorter for women (mean 3.6 days for women vs. 5.3 days for men, p = 0.0002). In the placebo group, the occurrence of vasospasm was not statistically different between the two groups. Primary causes of death and disability were the same, and favorable outcome rates at 3 months were not statistically different between the genders (69.7% for women vs. 73.4% for men, p = 0.243). The odds of a favorable outcome in women versus one in men were not statistically significant either before of after adjustment for age. These observations lead the authors to suggest that although women are older and harbor more aneurysms, the 3-month outcome for women and men who experience aneurysmal subarachnoid hemorrhage is the same.

A randomized trial of intraoperative, intracisternal tissue plasminogen activator for the prevention of vasospasm.

A multicenter, randomized, blinded, placebo-controlled trial was conducted to study the possible role of intracisternally administered fibrinolytic agent recombinant tissue plasminogen activator (rt-PA) in preventing delayed onset cerebral vasospasm following aneurysmal subarachnoid hemorrhage (SAH). The target population was patients with ruptured saccular aneurysms causing severe SAH, placing them at high risk for vasospasm. Treatment consisted of a single 10 ml intraoperative injection of either vehicle buffer solution or rt-PA (1 mg/ml) into the opened basal subarachnoid cisterns immediately following aneurysm clipping. The major efficacy endpoint in this trial was angiographic vasospasm, and the major safety concern was intracranial hemorrhage. One hundred patients were randomized, 49 to placebo and 51 to rt-PA treatment. Baseline population characteristics were similar between the two groups. Severity of intracranial hemorrhage on computed tomographic scans was also similar between groups: 87.2% of both placebo and rt-PA treated patients had thick subarachnoid clots, and the rates for intracerebral and intraventricular hemorrhage were, respectively, 16.3% and 22.5% for placebo and 23.5% and 21.6% for rt-PA. Nine randomized patients did not receive treatment in the operating room, and in 8 this was due to conditions felt unsafe for the administration of a fibrinolytic agent. The overall incidence of angiographic vasospasm measured between the seventh and eleventh day following SAH was similar between the two groups, with arterial narrowing detected in 74.4% of dosed placebo patients and 64.6% of rt-PA treated patients. However, there was a trend toward lesser degrees of vasospasm in the rt-PA treated group. The rates for no or mild, moderate, and severe vasospasm were 69%, 16% and 15% in the rt-PA treated group, versus 42%, 35% and 23% in the placebo group (P = 0.07). When only those patients with thick subarachnoid clots were considered at the treating centers, there was a 56% relative risk reduction of severe vasospasm in the rt-PA treated group, which was significant (P = 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Medical complications of aneurysmal subarachnoid hemorrhage: a report of the multicenter, cooperative aneurysm study. Participants of the Multicenter Cooperative Aneurysm Study.

OBJECTIVES: This report examines the frequency, type, and prognostic factors of medical (nonneurologic) complications after subarachnoid hemorrhage in a large, prospective study. The influences of contemporary neurosurgical, neurological, and critical care practice on mortality and morbidity rates after aneurysmal subarachnoid hemorrhage are evaluated. DESIGN: A study of medical complications observed in the placebo limb of a large, randomized, controlled trial of the calcium antagonist, nicardipine, after subarachnoid hemorrhage. SETTING: Patients were recruited from 50 hospitals in 41 neurosurgical centers in the United States and Canada. PATIENTS: A total of 457 patients with subarachnoid hemorrhage, > or = 18 yrs of age, were randomly assigned to the placebo group. All patients arrived at the participating center within 7 days (mean 1.0 +/- 1.8 [SD] days) of rupture of an angiographically documented saccular aneurysm. MEASUREMENTS AND MAIN RESULTS: The frequency rates of symptomatic vasospasm, rebleeding, and total mortality rate after subarachnoid hemorrhage at 3-month follow-up were 46%, 7%, and 19%, respectively. The frequency of having at least one severe (life-threatening) medical complication was 40%. The proportion of deaths from medical complications was 23%. This value was comparable with the proportion of deaths attributed to the direct effects of the initial hemorrhage (19%), rebleeding (22%), and vasospasm (23%) after aneurysmal rupture. The frequency of life-threatening cardiac arrhythmias was 5%; less ominous rhythm disturbances occurred in 30% of the patients. There was an increased frequency of cardiac arrhythmias on the day of, or day after, aneurysm surgery. Pulmonary edema occurred in 23% of the patients, with a 6% occurrence rate incidence of severe pulmonary edema. There was a wide variation from center to center, with the greatest frequency on days 3 through 7. There was a nonsignificant association of pulmonary edema with the use of hypertensive hypervolemic therapy (p = .10), and a significant association with the timing of surgery (p < .05). Some degree of hepatic dysfunction was noted in 24% of patients, the majority with only mild abnormalities of hepatic enzymes with no clinical accompaniment (4% frequency of severe hepatic dysfunction). Thrombocytopenia occurred in 4% of patients, usually in the setting of sepsis. Renal dysfunction was reported in 7% of the patients, with 15% of that figure deemed to be of life-threatening severity. There was an association (p = .001) with antibiotic therapy. CONCLUSIONS: Potentially preventable medical complications after ruptured cerebral aneurysm add to the total mortality rate of patients, and may increase length of hospital stay in the critical care setting. The proportion of deaths after subarachnoid hemorrhage from medical complications equals those deaths from either direct effects, rebleeding, or vasospasm individually. Pulmonary complications are the most common nonneurologic cause of death. Cardiac arrhythmia, although frequent, was not associated with significant mortality. The frequency of cardiac arrhythmia and pulmonary edema increased on the day of, or day after, aneurysm surgery. Renal and hepatic dysfunction, and blood dyscrasias, were also observed, underscoring the need for meticulous monitoring for metabolic and hematologic derangements.

Electrocardiographic abnormalities after nontraumatic subarachnoid hemorrhage.

Electrocardiographic (ECG) abnormalities and rhythm disorders are frequently observed in the acute phase after spontaneous subarachnoid hemorrhage (SAH). These abnormalities are benign and transient in most cases; however, in some patients they can take the form of life-threatening arrhythmias such as ventricular flutter/fibrillation and torsade de pointe. Among the ECG abnormalities observed, prolongation of the Q-T interval, especially if associated with hypokalemia, deserves particular attention because it is frequently present in those patients who will develop life-threatening ventricular arrhythmias. In some cases, the ECG abnormalities mimic those observed in the setting of acute myocardial infarction. Elevated creatine phosphokinase-myocardial fraction isoenzyme, suggesting underlying cardiac damage, has also been reported. The pathophysiology of these abnormalities is related to an imbalance of autonomic cardiovascular control. Because some electrical and morphological heart abnormalities are experimentally induced by catecholamine injection, the role of circulating catecholamines has been investigated in depth. Pathologically, the hearts of patients who die after SAH can show a peculiar morphological lesion defined as "myocytolysis." Intramyocardial hemorrhages have also been described. These observations confirm the utility of continuous cardiac monitoring in patients with SAH.

Angiographic characteristics of dural arteriovenous malformations that present with intracranial hemorrhage.

Dural arteriovenous malformations (dAVMs) are uncommon lesions that constitute about 12% of all the arteriovenous malformations. Depending on the location and the hemodynamics of the lesion, bruit, focal neurological deficit, and visual symptoms represent the more common presentation modalities. Although uncommon, intracranial hemorrhage can occur. In the present study, we report six patients with dural arteriovenous malformation that presented with intracranial hemorrhage. In five cases the hemorrhage was intraparenchymal (localized to the parietooccipital area in three), while it was confined to the subarachnoid space in the remaining one. The dAVM involved the transverse sinus in three cases, was based along the tentorial incisura in two, and was at the level of the torcular Herophili in one. Leptomeningeal drainage was present in all the cases. Aneurysmal dilatation of the draining vein(s) was identified in three. Sinus stenosis/occlusion was identified in two of the four patients with a dAVM draining into a major dural sinus. Four patients underwent pre-operative embolization, and all patients had surgical resection of their lesions. Anatomical cure, as defined by absence of any residual dAVM on postoperative angiogram, was achieved in all six patients. We conclude that several findings such as leptomeningeal drainage, location outside a major venous sinus, variceal dilatation, sinus stenosis/occlusion increase the risk of bleeding and are frequently observed in those dAVMs that present with intracranial hemorrhage. Recognition of these angiographic features is critical in planning a therapeutic approach tailored to the characteristics of the individual case. When these angiographic findings are present, prompt and definitive treatment is mandatory.(ABSTRACT TRUNCATED AT 250 WORDS)