Hyperglycemia in patients undergoing cerebral aneurysm surgery: its association with long-term gross neurologic and neuropsychological function

2023 Guideline for the Management of Patients With Aneurysmal Subarachnoid Hemorrhage: A Guideline From the American Heart Association/American Stroke Association

AIM

The "2023 Guideline for the Management of Patients With Aneurysmal Subarachnoid Hemorrhage" replaces the 2012 "Guidelines for the Management of Aneurysmal Subarachnoid Hemorrhage." The 2023 guideline is intended to provide patient-centric recommendations for clinicians to prevent, diagnose, and manage patients with aneurysmal subarachnoid hemorrhage.

METHODS

A comprehensive search for literature published since the 2012 guideline, derived from research principally involving human subjects, published in English, and indexed in MEDLINE, PubMed, Cochrane Library, and other selected databases relevant to this guideline, was conducted between March 2022 and June 2022. In addition, the guideline writing group reviewed documents on related subject matter previously published by the American Heart Association. Newer studies published between July 2022 and November 2022 that affected recommendation content, Class of Recommendation, or Level of Evidence were included if appropriate. Structure: Aneurysmal subarachnoid hemorrhage is a significant global public health threat and a severely morbid and often deadly condition. The 2023 aneurysmal subarachnoid hemorrhage guideline provides recommendations based on current evidence for the treatment of these patients. The recommendations present an evidence-based approach to preventing, diagnosing, and managing patients with aneurysmal subarachnoid hemorrhage, with the intent to improve quality of care and align with patients' and their families' and caregivers' interests. Many recommendations from the previous aneurysmal subarachnoid hemorrhage guidelines have been updated with new evidence, and new recommendations have been created when supported by published data.

Relationship between the mean of 24-h venous blood glucose and in-hospital mortality among patients with subarachnoid hemorrhage: A matched cohort study

Objective

The aim of this study was to explore the correlation between the mean of 24-h venous blood glucose (BG) and in-hospital mortality and all-cause mortality (ACM) in patients with subarachnoid hemorrhage (SAH).

Methods

Detailed clinical information was acquired from the Medical Information Mart for Intensive IV (MIMIC-IV) database. The best cutoff value of mean BG was calculated using the X-tile program. Univariate and multivariate logistic regressive analyses were utilized to analyze the prognosis significance of mean BG, and survival curves were drawn using the Kaplan-Meier (K-M) approach. To improve the reliability of results and balance the impact of underlying confounders, the 1:1 propensity score matching (PSM) approach was utilized.

Results

An overall of 1,230 subjects were selected herein. The optimal cutoff value of the mean BG for in-hospital mortality was 152.25. In addition, 367 pairs of score-matched subjects were acquired after PSM analysis, and nearly all variables' differences were balanced. K-M analysis showed that patients with mean BG ≥ 152.25 mg/dl had significantly higher in-hospital, 3-month, and 6-month mortalities compared with patients with mean BG < 152.25 mg/dl (p < 0.001). The multivariable logistic regressive analyses revealed that patients with mean BG ≥ 152.25 mg/dl had significantly increased in-hospital mortality compared with patients with mean BG < 152.25 mg/dl after the adjustment for possible confounders (OR = 1.994, 95% CI: 1.321–3.012, p = 0.001). Similar outcomes were discovered in the PSM cohort.

Conclusion

Our data suggested that mean BG was related to ACM of patients with SAH. More studies are needed to further analyze the role of the mean of 24-h venous BG in patients with SAH.

Perioperative Management of Aneurysmal Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage is an acute neurologic emergency. Prompt definitive treatment of the aneurysm by craniotomy and clipping or endovascular intervention with coils and/or stents is needed to prevent rebleeding. Extracranial manifestations of aneurysmal subarachnoid hemorrhage include cardiac dysfunction, neurogenic pulmonary edema, fluid and electrolyte imbalances, and hyperglycemia. Data on the impact of anesthesia on long-term neurologic outcomes of aneurysmal subarachnoid hemorrhage do not exist. Perioperative management should therefore focus on optimizing systemic physiology, facilitating timely definitive treatment, and selecting an anesthetic technique based on patient characteristics, severity of aneurysmal subarachnoid hemorrhage, and the planned intervention and monitoring. Anesthesiologists should be familiar with evoked potential monitoring, electroencephalographic burst suppression, temporary clipping, management of external ventricular drains, adenosine-induced cardiac standstill, and rapid ventricular pacing to effectively care for these patients.

Challenges in conducting long-term outcomes studies in critical care

PURPOSE OF REVIEW

Evaluating longer term mortality, morbidity, and quality of life in survivors of critical illness is a research priority. This review details the challenges of long-term follow-up studies of critically ill patients and highlights recently proposed methodological solutions.

RECENT FINDINGS

Barriers to long-term follow-up studies of critical care survivors include high rates of study attrition because of death or loss to follow-up, data missingness from experienced morbidity, and lack of standardized outcome as well as reporting of key covariates. A number of recent methods have been proposed to reduce study patients attrition, including minimum data set selection and visits to transitional care or home settings, yet these have significant downsides as well. Conducting long-term follow-up even in the absence of such models carries a high expense, as personnel are very costly, and patients/families require reimbursement for their time and inconvenience.

SUMMARY

There is a reason why many research groups do not conduct long-term outcomes in critical care: it is very difficult. Challenges of long-term follow-up require careful consideration by study investigators to ensure our collective success in data integration and a better understanding of underlying mechanisms of mortality and morbidity seen in critical care survivorship.

Intraoperative hyperglycemia increases the incidence of postoperative delirium

BACKGROUND

Hyperglycemia frequently occurs during major surgery and is associated with adverse postoperative outcomes. This study aimed to investigate the influence of intraoperative hyperglycemia on incidences of postoperative delirium (POD) and postoperative cognitive dysfunction (POCD).

METHODS

Eighty-seven patients aged ≥65 years undergoing elective surgery were included in this prospective observational subproject of the BioCog study. Blood glucose (BG) levels were measured every 20 minutes intraoperatively. Hyperglycemia was defined as BG levels ≥150 mg·dL-1. Patients were assessed for POD twice daily until postoperative day 7. The occurrence of POCD was determined three months after surgery. Multivariable logistic regression was used to identify associations between hyperglycemia and POD as well as POCD. Secondary endpoints comprised duration of hyperglycemia, maximum glucose level (Glucosemax) and differences between diabetic and non-diabetic patients.

RESULTS

POD occurred in 41 (47.1%), POCD in five (15.2%) patients. In two separate multivariable logistic regression models, hyperglycemia was significantly associated with POD (OR 3.86 [CI 95% 1.13, 39.49], P=0.044) but not POCD (3.59 [NaN, NaN], P=0.157). Relative duration of hyperglycemia was higher in POD patients compared to patients without POD (20 [0; 71] % versus 0 [0; 55] %, P=0.075), whereas the maximum glucose levels during surgery were similar between the two groups. Considering only non-diabetic patients, relative duration of hyperglycemia (P=0.003) and Glucosemax (P=0.015) were significantly higher in patients with POD.

CONCLUSIONS

Intraoperative hyperglycemia was independently associated with POD but not POCD. Relative duration of hyperglycemia appeared thereby to also play a role. Especially hyperglycemic non-diabetic patients might be at high risk for POD.

Risk Factors of Intraoperative Dysglycemia in Elderly Surgical Patients

BACKGROUNDː Dysglycemia is associated with adverse outcome including increased morbidity and mortality in surgical patients. Acute insulin resistance due to the surgical stress response is seen as a major cause of so-called stress hyperglycemia. However, understanding of factors determining blood glucose (BG) during surgery is limited. Therefore, we investigated risk factors contributing to intraoperative dysglycemia. METHODSː In this subgroup investigation of the BIOCOG study, we analyzed 87 patients of ≥ 65 years with tight intraoperative BG measurement every 20 min during elective surgery. Dysglycemia was defined as at least one intraoperative BG measurement outside the recommended target range of 80-150 mg/dL. Additionally, all postoperative BG measurements in the ICU were obtained. Multivariable logistic regression analysis adjusted for age, sex, American Society of Anesthesiologists (ASA) status, diabetes, type and duration of surgery, minimum Hemoglobin (Hb) and mean intraoperative norepinephrine use was performed to identify risk factors of intraoperative dysglycemia. RESULTSː 46 (52.9%) out of 87 patients developed intraoperative dysglycemia. 31.8% of all intraoperative BG measurements were detected outside the target range. Diabetes [OR 9.263 (95% CI 2.492, 34.433); p=0.001] and duration of surgery [OR 1.005 (1.000, 1.010); p=0.036] were independently associated with the development of intraoperative dysglycemia. Patients who experienced intraoperative dysglycemia had significantly elevated postoperative mean (p<0.001) and maximum BG levels (p=0.001). Length of ICU (p=0.007) as well as hospital stay (p=0.012) were longer in patients with dysglycemia. CONCLUSIONSː Diabetes and duration of surgery were confirmed as independent risk factors for intraoperative dysglycemia, which was associated with adverse outcome. These patients, therefore, might require intensified glycemic control. Increased awareness and management of intraoperative dysglycemia is warranted.

RS1 (Rsc1A1) deficiency limits cerebral SGLT1 expression and delays brain damage after experimental traumatic brain injury

Acute cerebral lesions are associated with dysregulation of brain glucose homeostasis. Previous studies showed that knockdown of Na⁺ -D-glucose cotransporter SGLT1 impaired outcome after middle cerebral artery occlusion and that widely expressed intracellular RS1 (RSC1A1) is involved in transcriptional and post-translational down-regulation of SGLT1. In the present study, we investigated whether SGLT1 is up-regulated during traumatic brain injury (TBI) and whether removal of RS1 in mice (RS1-KO) influences SGLT1 expression and outcome. Unexpectedly, brain SGLT1 mRNA in RS1-KO was similar to wild-type whereas it was increased in small intestine and decreased in kidney. One day after TBI, SGLT1 mRNA in the ipsilateral cortex was increased 160% in wild-type and 40% in RS1-KO. After RS1 removal lesion volume 1 day after TBI was reduced by 12%, brain edema was reduced by 28%, and motoric disability determined by a beam walking test was improved. In contrast, RS1 removal did neither influence glucose and glycogen accumulation 1 day after TBI nor up-regulation of inflammatory cytokines TNF-α, IL-1β and IL-6 or microglia activation 1 or 5 days after TBI. The data provide proof of principle that inhibition or down-regulation of SGLT1 by targeting RS1 in brain could be beneficial for early treatment of TBI.

Neuroanesthesiology Update

We provide a synopsis of innovative research, recurring themes, and novel experimental findings pertinent to the care of neurosurgical patients and critically ill patients with neurological diseases. We cover the following broad topics: general neurosurgery, spine surgery, stroke, traumatic brain injury, monitoring, and anesthetic neurotoxicity.

Korean Clinical Practice Guidelines for Aneurysmal Subarachnoid Hemorrhage

Despite advancements in treating ruptured cerebral aneurysms, an aneurysmal subarachnoid hemorrhage (aSAH) is still a grave cerebrovascular disease associated with a high rate of morbidity and mortality. Based on the literature published to date, worldwide academic and governmental committees have developed clinical practice guidelines (CPGs) to propose standards for disease management in order to achieve the best treatment outcomes for aSAHs. In 2013, the Korean Society of Cerebrovascular Surgeons issued a Korean version of the CPGs for aSAHs. The group researched all articles and major foreign CPGs published in English until December 2015 using several search engines. Based on these articles, levels of evidence and grades of recommendations were determined by our society as well as by other related Quality Control Committees from neurointervention, neurology and rehabilitation medicine. The Korean version of the CPGs for aSAHs includes risk factors, diagnosis, initial management, medical and surgical management to prevent rebleeding, management of delayed cerebral ischemia and vasospasm, treatment of hydrocephalus, treatment of medical complications and early rehabilitation. The CPGs are not the absolute standard but are the present reference as the evidence is still incomplete, each environment of clinical practice is different, and there is a high probability of variation in the current recommendations. The CPGs will be useful in the fields of clinical practice and research.

Management of hyperglycemia in the neurosurgery patient

Hyperglycemia is associated with adverse outcomes in patients who are candidates for or underwent neurosurgical procedures. Specific concerns and settings that relate to these patients are preoperative glycemic control, intraoperative control, management in the neurological intensive care unit (NICU), and postoperative control. In each of these settings, physicians have to ensure appropriate glycemic control to prevent or minimize adverse events. The glycemic control is usually managed by a neurohospitalist in co-management with the neurosurgery team pre- and post-operatively, and by the neurocritical care team in the setting of NICU. In this review article, we outline current standards of care for neurosurgery patients with diabetes mellitus and/or and hyperglycemia and discuss results of most recent clinical trials. We highlight specific concerns with regards to glycemic controls in these patients including enteral tube feeding and parenteral nutrition, the issues of the transition to the outpatient care, and management of steroid-induced hyperglycemia. We also note lack of evidence in some important areas, and the need for more research addressing these gaps. Where possible, we provide suggestions how to manage these patients when there is no underlying guideline.

Blood Glucose Variability: A Strong Independent Predictor of Neurological Outcomes in Aneurysmal Subarachnoid Hemorrhage

PURPOSE

In patients with aneurysmal subarachnoid hemorrhage (SAH), increased glucose variability (GV) is associated with increased mortality and cerebral infarction; however, there are no reports demonstrating an association between GV and neurological outcome. This study investigated whether GV had an independent effect on neurological outcomes in patients with SAH in the intensive care unit.

MATERIALS AND METHODS

Consecutive adult patients hospitalized with SAH between January 1, 2009, and May 31, 2015 (N = 122) were retrospectively reviewed. Univariate/multivariate analyses were performed to identify independent predictors of poor neurological outcome. Patients were divided according to the mean glucose level (80-139 vs 140-200 mg/dL) and further subdivided using quartiles (Q) of the standard deviation (SD, representing variability) of the glucose level (Q1, Q2 + 3, and Q4).

RESULTS

Unfavorable neurological outcomes occurred in 44.2% of the patients. On multiple regression analysis, age, Hunt and Kosnik grade, SD of glucose (odds ratio [OR], 1.09; 95% confidence interval [CI], 1.02-1.17; P < .01), and minimum blood glucose level (OR, 0.95; 95% CI, 0.91-0.99; P < .01) were significantly associated with unfavorable neurological outcomes. Both groups (mean glucose levels: 80-139 and 140-200 mg/dL groups) had increasing unfavorable neurological outcomes with increasing SD of glucose (Q1, 15.0%; Q2 + 3, 40.0%; Q4, 52.4% and Q1, 44.4%; Q2 + 3, 50%; Q4, 88.9% in the 80-139 and 140-200 mg/dL groups, respectively). Patients with minimum glucose of <90 mg/dL comprised >50% of unfavorable neurological outcome.

CONCLUSION

Increased GV was an independent predictor of unfavorable neurological outcomes in patients with SAH.

A minimum blood glucose value less than or equal to 120 mg/dL under glycemic control is associated with increased 14-day mortality in nondiabetic intensive care unit patients with sepsis and stress hyperglycemia

PURPOSE

Hyperglycemia is common in critically ill patients, but results of previous trials on glycemic control have been controversial. This study aimed to investigate whether the minimum blood glucose value during the first 72 hours after admission (72-min-BGV) was associated with mortality in patients with severe sepsis.

MATERIALS AND METHODS

This is a retrospective analysis of prospectively acquired clinical data from an intensive care unit of a tertiary referral hospital in central Taiwan. Patients were included if they were admitted due to severe sepsis from July 2010 to June 2011.

RESULTS

A total of 127 patients (100 males and 27 females) were included for analysis. A 72-min-BGV less than or equal to 120 mg/dL was associated with increased 14-day mortality. Further subgroup analysis revealed that this association existed only in the patients without diabetes. In multivariate logistic regression analysis, a 72-min-BGV less than or equal to 120 mg/dL was an independent risk factor for 14-day mortality (adjusted odds ratio, 5.09; 95% confidence interval, 1.26-23.33; P= .024) in the patients without diabetes.

CONCLUSIONS

A 72-min-BGV less than or equal to 120 mg/dL was an independent risk factor for 14-day mortality in nondiabetic patients with hyperglycemia admitted to our intensive care unit due to severe sepsis, but not in diabetic patients under the same setting.

Aneurysmal Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage (SAH) is a worldwide health burden with high fatality and permanent disability rates. The overall prognosis depends on the volume of the initial bleed, rebleeding, and degree of delayed cerebral ischemia (DCI). Cardiac manifestations and neurogenic pulmonary edema indicate the severity of SAH. The International Subarachnoid Aneurysm Trial (ISAT) reported a favorable neurological outcome with the endovascular coiling procedure compared with surgical clipping at the end of 1 year. The ISAT trial recruits were primarily neurologically good grade patients with smaller anterior circulation aneurysms, and therefore the results cannot be reliably extrapolated to larger aneurysms, posterior circulation aneurysms, patients presenting with complex aneurysm morphology, and poor neurological grades. The role of hypothermia is not proven to be neuroprotective according to a large randomized controlled trial, Intraoperative Hypothermia for Aneurysms Surgery Trial (IHAST II), which recruited patients with good neurological grades. Patients in this trial were subjected to slow cooling and inadequate cooling time and were rewarmed rapidly. This methodology would have reduced the beneficial effects of hypothermia. Adenosine is found to be beneficial for transient induced hypotension in 2 retrospective analyses, without increasing the risk for cardiac and neurological morbidity. The neurological benefit of pharmacological neuroprotection and neuromonitoring is not proven in patients undergoing clipping of aneurysms. DCI is an important cause of morbidity and mortality following SAH, and the pathophysiology is likely multifactorial and not yet understood. At present, oral nimodipine has an established role in the management of DCI, along with maintenance of euvolemia and induced hypertension. Following SAH, hypernatremia, although less common than hyponatremia, is a predictor of poor neurological outcome.

Prospective factors of temporary arterial occlusion during anterior communicating artery aneurysm repair

INTRODUCTION

This study was undertaken to determine variables that could predict, in the perioperative period of anterior communicating artery (ACom) aneurysms surgeries, the likelihood of postoperative sequelae and complications, after temporary arterial occlusion (TAO).

PATIENTS AND METHODS

In a universe of 32 patients submitted to ACom aneurysm repair in the last 7 years, 21 needed TAO intraoperatively, and had their data examined retrospectively.

RESULTS

Aneurysms larger than 7 mm were more likely to be treated with longer TAO time than small aneurysms, (p < 0.0001). There was no statistical correlation between time of occlusion and outcome. Age, Glasgow Coma Scale at initial evaluation, and Fisher scale at first CT scanning were independent factors of unfavorable outcome (p < 0.001). Meanwhile gender, tobacco addiction, obesity, arterial hypertension, dyslipidemia, location of TAO (A1 or A2), intraoperative rupture (IR) and the aneurysm size were not identified as independent prognostic factors.During follow-up period, two thirds of the patients had a favorable outcome, accomplishing normal daily life activities without major complications. Most patients developed clinical vasospasm (66.6 %), with 19 % of the patients harboring a severe disease. Delayed ischemic neurological deficit was observed in 28.5 %, without any statistical correlation to time of TAO or IR.

CONCLUSION

TAO during ACom aneurysm repair does not seem to add more morbidities to the procedure, and is not an independent prognostic factor.

General aspects of diabetes mellitus

Diabetes mellitus is a heterogeneous group of disorders characterized by hyperglycemia due to an absolute or relative deficit in insulin production or action. The chronic hyperglycemia of diabetes mellitus is associated with end organ damage, dysfunction, and failure, including the retina, kidney, nervous system, heart, and blood vessels. The International Diabetes Federation (IDF) estimated an overall prevalence of diabetes mellitus to be 366 million in 2011, and predicted a rise to 552 million by 2030. The treatment of diabetes mellitus is determined by the etiopathology and is most commonly subdivided in type 1 and type 2 diabetes mellitus. There is a greater propensity towards hyperglycemia in individuals with coexisting genetic predisposition or concomitant drug therapy such as corticosteroids. The screening for diabetes mellitus may either be in the form of a 2hour oral glucose tolerance test, or via HbA1c testing, as recently recommended by the American Diabetes Association (ADA). Strong associations have been shown in observational studies suggesting poor clinical outcomes both with chronic hyperglycemia and acutely in intensive care settings. However, tight glycemic control in this setting is a contentious issue with an increased incidence of hypoglycemia and possible increase in morbidity and mortality. In a critically ill patient a glucose range of 140-180mg/dL (7.8-10.0mmol/L) should be maintained via continuous intravenous insulin infusion.

Association of dysglycemia and all-cause mortality across the spectrum of coronary artery disease

OBJECTIVE

To assess the association between fasting plasma glucose (FPG) and all-cause mortality across the spectrum of coronary artery disease (CAD).

PATIENTS AND METHODS

The study included 18,999 patients during a study period of April 1, 2004, through October 31, 2010. The primary end points were in-hospital and follow-up all-cause mortality. According to the quartiles of FPG levels, patients were categorized into 4 groups: quartile 1, less than 5.1 mmol/L; quartile 2, 5.1 to less than 5.9 mmol/L; quartile 3, 5.9 to less than 7.5 mmol/L; and quartile 4, 7.5 mmol/L or greater. The conversion factor for units of plasma glucose is 1.00 mmol/L equals 18 mg/dL. Presented as mg/dL, the 4 quartile ranges of plasma glucose concentrations used in our data analysis are ≤90.0 mg/dL, 90.1-106.0 mg/dL, 106.1 mg/dL-135.0 mg/dL and ≥135.1 mg/dL. Quartile 1 was recognized as the lower glycemic group, quartiles 2 and 3 as the normoglycemic groups, and quartile 4 as the higher glycemic group.

RESULTS

In patients with acute myocardial infarction, all-cause mortality for the dysglycemic groups was higher than for the normoglycemic groups: in-hospital mortality for quartiles 1, 2, 3, and 4 was 1.0%, 0.9%, 0.2%, and 1.5%, respectively (P=.001); follow-up mortality for quartiles 1, 2, 3, and 4 was 1.7%, 0.9%, 0.3%, and 1.8%, respectively (P<.001). In patients with stable CAD, no significant differences in mortality were found among groups. However, in patients with unstable angina pectoris, the normoglycemic groups had lower follow-up mortality and roughly equal in-hospital mortality compared with the dysglycemic groups. After adjusting for confounding factors, this observation persisted.

CONCLUSION

The association between lower FPG level and mortality differed across the spectrum of CAD. In patients with acute myocardial infarction, there was a U-shaped relationship. In patients with stable CAD or unstable angina pectoris, mildly to moderately decreasing FPG level was associated with neither higher nor lower all-cause mortality.

Research studies that have influenced practice of neuroanesthesiology in recent years: A literature review

Through evolving research, recent years have witnessed remarkable achievements in neuromonitoring and neuroanesthetic techniques, with a huge body of literature consisting of excellent studies in neuroanaesthesiology. However, little of this work appears to be directly important to clinical practice. Many controversies still exist in care of patients with neurologic injury. This review discusses studies of great clinical importance carried out in the last five years, which have the potential of influencing our current clinical practice and also attempts to define areas in need of further research. Relevant literature was obtained through multiple sources that included professional websites, medical journals and textbooks using key words “neuroanaesthesiology,” “traumatic brain injury,” “aneurysmal subarachnoid haemorrhage,” “carotid artery disease,” “brain protection,” “glycemic management” and “neurocritical care.” In head injured patients, administration of colloid and pre-hospital hypertonic saline resuscitation have not been found beneficial while use of multimodality monitoring, individualized optimal cerebral perfusion pressure therapy, tranexamic acid and decompressive craniectomy needs further evaluation. Studies are underway for establishing cerebroprotective potential of therapeutic hypothermia. Local anaesthesia provides better neurocognitive outcome in patients undergoing carotid endarterectomy compared with general anaesthesia. In patients with aneurysmal subarachnoid haemorrhage, induced hypertension alone is currently recommended for treating suspected cerebral vasospasm in place of triple H therapy. Till date, nimodipine is the only drug with proven efficacy in preventing cerebral vasospasm. In neurocritically ill patients, intensive insulin therapy results in substantial increase in hypoglycemic episodes and mortality rate, with current emphasis on minimizing glucose variability. Results of ongoing multicentric trials are likely to further improvise our practice.

Patterns in neurosurgical adverse events: open cerebrovascular neurosurgery

OBJECT

As part of a project to devise evidence-based safety interventions for specialty surgery, we sought to review current evidence concerning the frequency of adverse events in open cerebrovascular neurosurgery and the state of knowledge regarding methods for their reduction. This review represents part of a series of papers written to consolidate information about these events and preventive measures as part of an ongoing effort to ascertain the utility of devising system-wide policies and safety tools to improve neurosurgical practice.

METHODS

The authors performed a PubMed search using search terms "cerebral aneurysm", "cerebral arteriovenous malformation", "intracerebral hemorrhage", "intracranial hemorrhage", "subarachnoid hemorrhage", and "complications" or "adverse events." Only papers that specifically discussed the relevant complication rates were included. Papers were chosen to be included to maximize the range of rates of occurrence for the reported adverse events.

RESULTS

The review revealed hemorrhage-related hyperglycemia (incidence rates ranging from 27% to 71%) and cerebral salt-wasting syndromes (34%-57%) to be the most common perioperative adverse events related to subarachnoid hemorrhage (SAH). Next in terms of frequency was new cerebral infarction associated with SAH, with a rate estimated at 40%. Many techniques are advocated for use during surgery to minimize risk of this development, including intraoperative neurophysiological monitoring, but are not universally used due to surgeon preference and variable availability of appropriate staffing and equipment. The comparative effectiveness of using or omitting monitoring technologies has not been evaluated. The incidence of perioperative seizure related to vascular neurosurgery is unknown, but reported seizure rates from observational studies range from 4% to 42%. There are no standard guidelines for the use of seizure prophylaxis in these patients, and there remains a need for prospective studies to support such guidelines. Intraoperative rupture occurs at a rate of 7% to 35% and depends on aneurysm location and morphology, history of rupture, surgical technique, and surgeon experience. Preventive strategies include temporary vascular clipping. Technical adverse events directly involving application of the aneurysm clip include incomplete aneurysm obliteration and parent vessel occlusion. The rates of these events range from 5% to 18% for incomplete obliteration and 3% to 12% for major vessel occlusion. Intraoperative angiography is widely used to confirm clip placement; adjuncts include indocyanine green video angiography and microvascular Doppler ultrasonography. Use of these technologies varies by institution.

DISCUSSION

A significant proportion of these complications may be avoidable through development and testing of standardized protocols to incorporate monitoring technologies and specific technical practices, teamwork and communication, and concentrated volume and specialization. Collaborative monitoring and evaluation of such protocols are likely necessary for the advancement of open cerebrovascular neurosurgical quality.

Guidelines for the use of an insulin infusion for the management of hyperglycemia in critically ill patients

OBJECTIVE

To evaluate the literature and identify important aspects of insulin therapy that facilitate safe and effective infusion therapy for a defined glycemic end point.

METHODS

Where available, the literature was evaluated using Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) methodology to assess the impact of insulin infusions on outcome for general intensive care unit patients and those in specific subsets of neurologic injury, traumatic injury, and cardiovascular surgery. Elements that contribute to safe and effective insulin infusion therapy were determined through literature review and expert opinion. The majority of the literature supporting the use of insulin infusion therapy for critically ill patients lacks adequate strength to support more than weak recommendations, termed suggestions, such that the difference between desirable and undesirable effect of a given intervention is not always clear.

RECOMMENDATIONS

The article is focused on a suggested glycemic control end point such that a blood glucose ≥ 150 mg/dL triggers interventions to maintain blood glucose below that level and absolutely <180 mg/dL. There is a slight reduction in mortality with this treatment end point for general intensive care unit patients and reductions in morbidity for perioperative patients, postoperative cardiac surgery patients, post-traumatic injury patients, and neurologic injury patients. We suggest that the insulin regimen and monitoring system be designed to avoid and detect hypoglycemia (blood glucose ≤ 70 mg/dL) and to minimize glycemic variability.Important processes of care for insulin therapy include use of a reliable insulin infusion protocol, frequent blood glucose monitoring, and avoidance of finger-stick glucose testing through the use of arterial or venous glucose samples. The essential components of an insulin infusion system include use of a validated insulin titration program, availability of appropriate staffing resources, accurate monitoring technology, and standardized approaches to infusion preparation, provision of consistent carbohydrate calories and nutritional support, and dextrose replacement for hypoglycemia prevention and treatment. Quality improvement of glycemic management programs should include analysis of hypoglycemia rates, run charts of glucose values <150 and 180 mg/dL. The literature is inadequate to support recommendations regarding glycemic control in pediatric patients.

CONCLUSIONS

While the benefits of tight glycemic control have not been definitive, there are patients who will receive insulin infusion therapy, and the suggestions in this article provide the structure for safe and effective use of this therapy.

Protecting the brain during neurosurgical procedures: strategies that can work

PURPOSE OF REVIEW

The quest for neuroprotection strategies during periods of neuronal vulnerability persists despite decades of basic and clinical research. This review will focus on the latest developments in the area of clinical brain protection with the major emphasis on strategies that can be beneficial during neurosurgical procedures.

RECENT FINDINGS

Brain protection in neurosurgical patients may be achieved by nonpharmacological and pharmacological strategies. Pharmacological neuroprotection including anaesthetic administration have not been recently shown to be successful. Alternatively, nonpharmacological strategies including maintenance of cerebral perfusion by adequate control of mean arterial pressure (≥80 mmHg), liberal normoglycaemia (7.8-10 mmol/l), adequate haemoglobin levels (preoperative ≥120 g/l and intraoperative ≥90 g/l) and induction of hypertension (20-40% of preoperative values) in certain neurosurgical situations can be beneficial as neuroprotectants during neurosurgery. Mild hypothermia (32-35°C) failed to achieve neuroprotective effects in several situations of brain injury.

SUMMARY

The findings of this review suggest that the anaesthesiologist is compelled to use nonpharmacological strategies sometimes based on empiric evidence to protect the brain during neurosurgical procedures. These strategies are simple, have high benefit/risk ratios and are inexpensive. Rigorous controlled clinical studies are needed to investigate the neuroprotective efficacy of these commonly used nonpharmacological methods.

Guidelines for the management of aneurysmal subarachnoid hemorrhage: a guideline for healthcare professionals from the American Heart Association/american Stroke Association

PURPOSE

The aim of this guideline is to present current and comprehensive recommendations for the diagnosis and treatment of aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

A formal literature search of MEDLINE (November 1, 2006, through May 1, 2010) was performed. Data were synthesized with the use of evidence tables. Writing group members met by teleconference to discuss data-derived recommendations. The American Heart Association Stroke Council's Levels of Evidence grading algorithm was used to grade each recommendation. The guideline draft was reviewed by 7 expert peer reviewers and by the members of the Stroke Council Leadership and Manuscript Oversight Committees. It is intended that this guideline be fully updated every 3 years.

RESULTS

Evidence-based guidelines are presented for the care of patients presenting with aSAH. The focus of the guideline was subdivided into incidence, risk factors, prevention, natural history and outcome, diagnosis, prevention of rebleeding, surgical and endovascular repair of ruptured aneurysms, systems of care, anesthetic management during repair, management of vasospasm and delayed cerebral ischemia, management of hydrocephalus, management of seizures, and management of medical complications.

CONCLUSIONS

aSAH is a serious medical condition in which outcome can be dramatically impacted by early, aggressive, expert care. The guidelines offer a framework for goal-directed treatment of the patient with aSAH.

Spontaneous subarachnoid hemorrhage and glucose management

Although metabolic abnormalities have been linked with poor outcome after subarachnoid hemorrhage, there are limited data addressing the impact of glycemic control or benefits of glucose management after aneurysmal subarachnoid hemorrhage. A systematic literature search was conducted of English-language articles describing original research on glycemic control in patients with subarachnoid hemorrhage. Case reports and case series were excluded. A total of 22 publications were selected for this review. Among the 17 studies investigating glucose as an outcome predictor, glucose levels during hospitalization were more likely to predict outcome than admission glucose. In general, hyperglycemia was linked to worse outcome. While insulin therapy in subarachnoid hemorrhage patients was shown to effectively control plasma glucose levels, plasma glucose control was not necessarily reflective of cerebral glucose such that very tight glucose control may lead to neuroglycopenia. Furthermore, tight glycemic control was associated with an increased risk for hypoglycemia which was linked to worse outcome.

Natural history and medical treatment of cognitive dysfunction after spontaneous subarachnoid haemorrhage: review of current literature with respect to aneurysm treatment

Aneurysmal subarachnoid haemorrhage (aSAH) has the highest mortality and morbidity among all types of stroke. Unfortunately, cognitive dysfunction remains a major problem to those who survive the acute crisis. Most studies focused on patients after microsurgical clipping, which turned out to be different from the modern patient cohorts. With the widespread introduction of endovascular surgery as the first choice of treatment, there was a hope that post-aSAH cognitive dysfunction could be markedly reduced. However, data showed that post-aSAH cognitive dysfunction remained a major burden to the survivors of our modern patient cohort that returned to the community more than nine months after the initial haemorrhage. There is, therefore, a need to further understand its pathophysiology and natural history, and to develop effective treatment strategy. The results are encouraging and further clinical studies are indicated. Collaborations between cognitive scientists, neurologists and neurosurgeons are essential to advance the understanding of the problem.

Perioperative hypothermia (33 degrees C) does not increase the occurrence of cardiovascular events in patients undergoing cerebral aneurysm surgery: findings from the Intraoperative Hypothermia for Aneurysm Surgery Trial

BACKGROUND

Perioperative hypothermia has been reported to increase the occurrence of cardiovascular complications. By increasing the activity of sympathetic nervous system, perioperative hypothermia also has the potential to increase cardiac injury and dysfunction associated with subarachnoid hemorrhage.

METHODS

The Intraoperative Hypothermia for Aneurysm Surgery Trial randomized patients undergoing cerebral aneurysm surgery to intraoperative hypothermia (n = 499, 33.3 degrees +/- 0.8 degrees C) or normothermia (n = 501, 36.7 degrees +/- 0.5 degrees C). Cardiovascular events (hypotension, arrhythmias, vasopressor use, myocardial infarction, and others) were prospectively followed until 3-month follow-up and were compared in hypothermic and normothermic patients. A subset of 62 patients (hypothermia, n = 33; normothermia, n = 29) also had preoperative and postoperative (within 24 h) measurement of cardiac troponin-I and echocardiography to explore the association between perioperative hypothermia and subarachnoid hemorrhage-associated myocardial injury and left ventricular function.

RESULTS

There was no difference between hypothermic and normothermic patients in the occurrence of any single cardiovascular event or in composite cardiovascular events. There was no difference in mortality (6%) between groups, and there was only a single primary cardiovascular death (normothermia). There was no difference between hypothermic and normothermic patients in postoperative versus preoperative left ventricular regional wall motion or ejection fraction. Compared with preoperative values, hypothermic patients had no postoperative increase in cardiac troponin-I (median change 0.00 microg/l), whereas normothermic patients had a small postoperative increase (median change + 0.01 microg/l, P = 0.038).

CONCLUSION

In patients undergoing cerebral aneurysm surgery, perioperative hypothermia was not associated with an increased occurrence of cardiovascular events.

Medical complications after subarachnoid hemorrhage

The prevention and management of medical complications are important for improving outcomes after subarachnoid hemorrhage (SAH). Fever, anemia requiring transfusion, hyperglycemia, hyponatremia, pneumonia, hypertension, and neurogenic cardiopulmonary dysfunction occur frequently after SAH. There is increasing evidence that acute hypoxia and extremes of blood pressure can exacerbate brain injury during the acute phase of bleeding. There are promising strategies to minimize these complications. Randomized controlled trials are needed to evaluate the risks and benefits of these and other medical management strategies after SAH.

Scientific principles and clinical implications of perioperative glucose regulation and control

Development of hyperglycemia after major operations is very common and is modulated by many factors. These factors include perioperative metabolic state, intraoperative management of the patient, and neuroendocrine stress response to surgery. Acute insulin resistance also develops perioperatively and contributes significantly to hyperglycemia. Hyperglycemia is associated with poor outcomes in critically ill and postsurgical patients. A majority of the investigations use the term "hyperglycemia" very loosely and use varying thresholds for initiating treatment. Initial studies demonstrated improved outcomes in critically ill, postsurgical patients who received intensive glycemic control (IGC) (target serum glucose <110 mg/dL). These results were quickly extrapolated to other clinical areas, and IGC was enthusiastically recommended in the perioperative period. However, there are few studies investigating the value of intraoperative glycemic control. Moreover, recent prospective trials have not been able to show the benefit of IGC; neither an appropriate therapeutic glycemic target nor the true efficacy of perioperative glycemic control has been fully determined. Practitioners should also appreciate technical nuances of various glucose measurement techniques. IGC increases the risk of hypoglycemia significantly, which is not inconsequential in critically ill patients. Until further specific data are accumulated, it is prudent to maintain glucose levels <180 mg/dL in the perioperative period, and glycemic control should always be accompanied by close glucose monitoring.