Aneurysmal subarachnoid haemorrhage and the anaesthetist

Prognostic value of platelet levels in patients with aneurysmal Subarachnoid Hemorrhage

Pathophysiological processes following aneurysmal subarachnoid hemorrhage (aSAH) include upregulated underlying systemic inflammation, which is reflected by changes in different peripheral blood cells and their sub-populations. As inflammation is a crucial process that contributes to post-aSAH complications and clincal outcome, blood cell numbers and ratios in systemic circulation may predict the outcome and provide rapid and easy to quantify point of care biomarkers for these critically ill patients. To identify blood-derived cellular inflammatory parameters which allow a precise prediction of patient outcome after aSAH. In this single-center retrospective study, 19 whole blood-derived cellular inflammatory markers and clinical and demographic parameters for 101 aSAH patients were recorded within 24 h after aSAH. Clinical outcome was quantified with modified Rankin scale (mRS) on discharge. Proportional odds logistic regression (POLR) was used to model the patient outcome as the function of clinical parameters and inflammatory markers. The results were validated on a separate hold-out dataset (220 patients). The on-admission platelet count, mean platelet volume (MPV) and mean platelet volume to platelet ratio (MPR) were found to be significant and predictive of patient outcome on discharge. Mean platelet volume (MPV) and mean platelet volume to platelet ratio (MPR) predicted clinical outcome and may serve as easy to quantify point of care biomarker. The findings are potentially relevant for the management of aSAH.

Mortality After Microsurgical Treatment of Unruptured Intracranial Aneurysms in the Modern Era

BACKGROUND

The incidence of mortality after treatment of unruptured intracranial aneurysms (UIAs) has been described historically. However, many advances in microsurgical treatment have since emerged, and most available data are outdated. We analyzed the incidence of mortality after microsurgical treatment of patients with UIAs treated in the past decade.

METHODS

The medical records of all patients with UIAs who underwent elective treatment at our large quaternary center from January 1, 2014, to December 31, 2020, were reviewed retrospectively. We analyzed mortality at discharge and 1-year follow-up as the primary outcome using univariate to multivariable progression with P < 0.20 inclusion.

RESULTS

During the 7-year study period, 488 patients (mean [SD] age = 58 [12] years) had UIAs treated microsurgically. Of these patients, 61 (12.5%) had a prior subarachnoid hemorrhage. One patient (0.2%) with a dolichoectatic vertebrobasilar aneurysm died while hospitalized, and 7 other patients (8 total; 1.6%) were determined to have died at 1-year follow-up (1 trauma, 2 myocardial infarction, 2 cerebrovascular accident, 1 pulmonary embolism, and 1 subdural hematoma complicated by abscess). On univariate analysis, significant risk factors for mortality at follow-up included diabetes mellitus, preoperative anticoagulant or antiplatelet use, aneurysm calcification, nonsaccular aneurysm, and higher American Society of Anesthesiologists grades (all P < 0.03). On multivariable logistic regression analysis, only nonsaccular aneurysms and higher American Society of Anesthesiologists grades were predictors of mortality.

CONCLUSIONS

A low mortality rate is associated with recent microsurgical treatment of UIAs. However, nonsaccular aneurysms and higher American Society of Anesthesiologists grades appear to be predictors of mortality.

Cerebral Perfusion Pressure-Guided Therapy in Patients with Subarachnoid Haemorrhage-A Retrospective Analysis

BACKGROUND

Prevention and treatment of haemodynamic instability and increased intracranial pressure (ICP) in patients with subarachnoid haemorrhage (SAH) is vital. This study aimed to evaluate the effects of protocolised cerebral perfusion pressure (CPP)-guided treatment on morbidity and functional outcome in patients admitted to the intensive care unit (ICU) with SAH.

METHODS

We performed a retrospective study comparing 37 patients who received standard haemodynamic treatment (control group) with 17 individuals (CPP-guided group) who were on the CPP-guided treatment aimed at maintaining CPP > 70 mmHg using both optimisations of ICP and mean arterial pressure (MAP).

RESULTS

MAP, cumulative crystalloid doses and fluid balance were similar in both groups. However, the incidence of delayed cerebral ischaemia was significantly lower in the CPP-guided group (14% vs. 64%, p < 0.01), and functional outcome as assessed by the Glasgow Outcome Scale at 30 days after SAH was improved (29.0% vs. 5.5%, p = 0.03).

CONCLUSIONS

This preliminary analysis showed that implementing a CPP-guided treatment approach aimed at maintaining a CPP > 70 mmHg may reduce the occurrence of delayed cerebral ischaemia and improve functional outcomes in patients with SAH. This observation merits further prospective investigation of the use of CPP-guided treatment in patients with SAH.

Clustering of serum biomarkers involved in post-aneurysmal subarachnoid hemorrhage (aSAH) complications

Post-aSAH sequela is characterized by the onset of life-threatening complications along with the upregulated underlying inflammation. Cerebral vasospasm (CVS) is one of the most frequent complication after aSAH, which contributes majorly to delayed cerebral ischemia and poor clinical outcome. The objective of this study was to identify the clusters of serum biomarkers that are associated with cerebral vasospasm (CVS) after suffering from aneurysmal subarachnoid hemorrhage (aSAH). In this single-center study, serum concentrations of 10 potential biomarkers, together with clinical and demographic parameters, for 66 aSAH patients were recorded within 24 h after aSAH. The dataset was split into a training set (43 patients) and a validation set. Correlation heatmaps for both datasets were computed. Variables with inconsistent correlations on the two subsets were excluded. Clusters of relevant biomarkers were identified on the complete set, separately for patients who developed post-aSAH CVS and those who did not. Two clusters were found to be specific for patients who suffered from CVS: mitochondrial gene fragments (cytochrome B (Cyt-B), cytochrome C oxidase subunit-1 (Cox-1), displacement loop (D-loop), and IL-23, and the other one, containing IL-6, IL-10, age, and Hunt and Hess score. Clusters of serum biomarkers, analyzed within 24 h of the onset of aSAH, days before the CVS development, are expressed differently in patients suffering from post-aSAH CVS, compared to patients without CVS. This suggests that these biomarkers may be involved in the pathophysiological processes leading to CVS and may be used as its early predictors. These interesting findings are potentially highly relevant for the management of CVS and call for validation on a larger sample of patients.

Avoiding Complications in Aneurysm Ligation: Operative Tips and Tricks

Preventing possible complications during brain aneurysm surgery is mandatory to ensure a better outcome for patients. Currently, it is possible to rely on some technologic innovations such as motor evoked potential, endoscope-assisted surgery, dye with indocyanine green, and video angiography capable of supporting the surgeon's work. The innovation process has mainly assisted the endovascular technique compared with surgery. The latter, apart from some new technical expedients, always requires anatomic knowledge and optimal technical preparation. A careful patient selection, adequate surgical exposure, use of microsurgical techniques in expert hands, and meticulous postoperative management represent the key to success for the surgical treatment of cerebral aneurysms.

It.ÇÖs not always postdural puncture headache: a case report and note to the astute anesthesiologist

Dural puncture is either diagnosed by unexpectedly profound response to medication test dose or development of a postpartum postural headache. Epidural blood patch is the gold standard for treatment of PDPH when conservative management fails. However, postpartum headaches can be resistant to multiple epidural blood patches. In such cases, preexisting intracranial processes should be considered and ruled out. We report here the unique case of a pregnant patient who developed a resistant headache in the postpartum period related to an incidental intracranial aneurysm. Subsequent treatment with endovascular embolization adequately relieved her symptoms. Early surgical consultation and a multidisciplinary team approach involving neurology and neuroimaging is required for successful management of patients such as the one described here.

Comparison of Ketofol (Combination of Ketamine and Propofol) and Propofol Anesthesia in Aneurysmal Clipping Surgery: A Prospective Randomized Control Trial

Background:

The maintenance of hemodynamic stability is of pivotal importance in aneurysm surgeries. While administering anesthesia in these patients, the fluctuations in blood pressure may directly affect transmural pressure, thereby precipitating rupture of aneurysm and various other associated complications. We aimed to compare the effects of ketofol with propofol alone when used as an induction and maintenance anesthetic agent during surgical clipping of intracranial aneurysms.

Materials and Methods:

Forty adult, good-grade aneurysmal subarachnoid hemorrhage patients posted for aneurysm neck clipping were included in the study. The patients were randomized into two groups. One group received a combination of ketamine and propofol (1:5 ratio) and the other group received propofol for induction and maintenance of anesthesia. Intraoperative hemodynamic stability, intraventricular pressure, and quality of brain relaxation were studied in both the groups.

Results:

The patients were comparable with respect to demographic profile, Hunt and Hess grade, world federation of neurological surgeons (WFNS) grade, Fisher grade, duration of anesthesia, duration of surgery, optic nerve sheath diameter, and baseline hemoglobin. Intraoperative hemodynamics were better maintained in the ketofol group during induction, with only 15% of patients having >20% fall in mean arterial pressure (from baseline) intraoperatively, compared to 45% of patients receiving propofol alone (P = 0.038). The mean intraventricular pressure values in both the groups were in the normal range and the quality of brain relaxation was similar, with no significant difference (P > 0.05).

Conclusion:

Ketofol combination (1:5) as compared to propofol alone provides better hemodynamic stability on induction as well as maintenance anesthesia without causing an increase in intracranial pressure. Effect of ketofol on cerebral oxygenation and quality of emergence need to be evaluated further by larger multicentric, randomized control trials.

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.

Mycotic Aneurysm of the Extracranial Internal Carotid Artery Following Otitis Media

Mycotic aneurysm of the internal carotid artery following otomastoiditis can manifest as a nasopharyngeal mass. This is a very rarely described condition. The case of a patient diagnosed with a retropharyngeal mycotic aneurysm of the left internal carotid artery following otitis media, treated with exclusion of the mycotic aneurysm from the circulation and transnasal drainage. Infection of the mastoid can spread to the parapharyngeal space of the nasopharynx and damage the carotid artery wall, resulting in an infected aneurysm. There are no guidelines on how to surgically approach those aneurysms. An endoscopic transnasal approach can be beneficial.

The Nimodipine-Sparing Effect of Perioperative Dexmedetomidine Infusion During Aneurysmal Subarachnoid Hemorrhage: A Prospective, Randomized, Controlled Trial

Background: Nimodipine can block the influx of calcium into the vascular smooth muscle cell and prevent secondary ischemia in patients with aneurysmal subarachnoid hemorrhage. However, the reduction of blood pressure after long-term intravenous administration of nimodipine has been associated with neurological deterioration. Yet, no effective solutions have been suggested to address this phenomenon. The use of neuroprotective drug combinations may reduce the risk of sudden blood pressure loss. This prospective, randomized, controlled trial was performed to evaluate the nimodipine-sparing effect of perioperative dexmedetomidine infusion during aneurysmal subarachnoid hemorrhage.

Methods: One hundred nine patients who underwent aneurysm embolization were divided into three groups: group C (n = 35, infused with 0.9% sodium chloride at the same rate as other two groups), group D1 (n = 38, dexmedetomidine infusion at 0.5 µg·kg^–1 for 10 min, then adjusted to 0.2 µg·kg^–1·h^–1), and group D2 (n = 36, dexmedetomidine infusion at 0.5 µg·kg^–1 for 10 min, then adjusted to 0.4 µg·kg^–1·h^–1). Patient-controlled analgesia was given for 48 h after surgery. The primary outcome measure was the total consumption of nimodipine during the first 48 h after surgery. The secondary outcome measures were recovery time at post-anesthesia care unit (PACU), postoperative pain intensity scores, dexmedetomidine and sufentanil consumption, hemodynamic, satisfaction of patients and neurosurgeon, neurologic examination (Glasgow Coma Scale, GCS), Bruggemann comfort scale, and adverse effects. Intraoperative hemodynamics were recorded at the following time-points: arrival at the operating room (T1); before intubation (T2); intubation (T3); 5 min (T4), 10 min (T5), and 15 min (T6) after intubation; suturing of femoral artery (T7); end of surgery (T8); extubation (T9); and 5 min (T10), 10 min (T11), and 15 min (T12) after arrival at the PACU. The level of sedation was recorded at 15 min, 30 min, 1 h, and 2 h after extubation. We also recorded the incidence of symptomatic cerebral vasospasm during 7 days after surgery, Glasgow Outcome Score (GOS) at 3 months, and incidence of cerebral infarction 30 days after surgery.

Results: The consumption of nimodipine during the first 48 h after surgery was significantly lower in group D2 (P < 0.05). Compared with group C, HR and MAP were significantly decreased from T2 to T12 in group D1 and D2 (P < 0.05). Patients in group D2 showed a significantly decreased MAP from T5 to T9 compared with group D1 (P < 0.05). The consumption of sevoflurane, remifentanil, dexmedetomidine, and nimodipine were all significantly reduced in groups D1 and D2 during surgery (P < 0.05). Compared with group C, MAP was significantly decreased in groups D1 and D2 during the first 48 h after surgery (P < 0.05). Compared with group C, consumption of sufentanil and dexmedetomidine at 1 h, pain intensity at 1 h, and 8 h after surgery were significantly decreased in groups D1 and D2 (P < 0.05). FAS was significantly higher in group D2 at 8 h, 16 h, and 24 h after surgery. LOS was significantly lower only in group D2 at 0.5 h after surgery (P < 0.05). Compared with group C, BCS was significantly higher group D2 at 4 h and 8 h after surgery (P < 0.05). There were no significant differences among the three groups in consumption of propofol, cisatracurium, fentanyl, and vasoactive drugs during operation, recovery time at PACU, satisfaction of patients and neurosurgeon, and number of applied urapidil and GCS during the first 48 h after surgery. The incidence of symptomatic cerebral vasospasm during 7 days after surgery, GOS of 3 months, and cerebral infarction after 30 days were also comparable among the three groups.

Conclusions: Dexmedetomidine (infusion at 0.5 µg·kg^–1 for 10 min, then adjusted to 0.4 µg·kg^–1·h^–1 during the surgery) significantly reduced the total consumption of nimodipine during the first 48 h after surgery and promoted early rehabilitation of patients although the incidences of symptomatic cerebral vasospasm, GOS, and cerebral infarction were not reduced.

Haplotype analysis of SERPINE1 gene: Risk for aneurysmal subarachnoid hemorrhage and clinical outcomes

Background

Aneurysmal subarachnoid hemorrhage (aSAH) has high fatality and permanent disability rates due to the severe damage to brain cells and inflammation. The SERPINE1 gene that encodes PAI‐1 for the regulation of tissue plasminogen activator is considered an important therapeutic target for aSAH.

Methods

Six SNPs in the SERPINE1 gene (in order of rs2227631, rs1799889, rs6092, rs6090, rs2227684, rs7242) were investigated. Blood samples were genotyped with Taqman genotyping assays and pyrosequencing. The experiment‐wide statistically significant threshold for single marker analysis was set at p < 0.01 after evaluation of independent markers. Haplotype analysis was performed in Haplo.stats package with permutation tests. Bonferroni correction for multiple comparison in dominant, additive, and recessive model was applied.

Results

A total of 146 aSAH patients and 49 control subjects were involved in this study. The rs2227631 G allele is significant (p = 0.01) for aSAH compared to control. In aSAH group, haplotype analysis showed that G5GGGT homozygotes in recessive model were associated with delayed cerebral ischemia (p < 0.01, Odds Ratio = 5.14, 95% CI = 1.45–18.18), clinical vasospasm (p = 0.01, Odds Ratio = 4.58, 95% CI = 1.30–16.13), and longer intensive care unit stay (p = 0.01). By contrast, the G5GGAG carriers were associated with less incidence of cerebral edema (p < 0.01) and higher Glasgow Coma Scale (p < 0.01). The A4GGGT carriers were associated with less incidence of severe hypertension (>140/90) (p < 0.01).

Conclusion

The results suggested an important regulatory role of the SERPINE1 gene polymorphism in clinical outcomes of aSAH.

A Case Report of Thalamic Infarction after Lumbar Drain: A Unique Cause of Perioperative Stroke?

In the case presented, a patient has an unexplained episode of hypertension during aneurysm clipping. Following the procedure, the patient was discovered to have bilateral thalamic infarctions unrelated to the vascular location of the aneurysm. After a review of the case, it becomes apparent that intracranial hypotension caused by lumbar over drainage of cerebrospinal fluid (CSF) is the likely cause of both the episode of intraoperative hypertension and the thalamic infarcts. It is often presumed that having an open dura protects against intracranial hypotension and subsequent herniation. We present this case to suggest that opening the dura might not be protective in all cases and anesthesiologists must pay particular attention to the rate of CSF drainage. Lumbar CSF drainage is a technique frequently employed during neurological surgery and it is important for anesthesiologists to understand the signs, symptoms, and potential consequences of intracranial hypotension from rapid drainage.

Neuroanesthesia and pregnancy: Uncharted waters

An incidence of 30-40 deaths per triennium in pregnant patients is reported because of brain pathology. Over the last two decades, the obstetric cause of mortality in the pregnant patient has declined, but the trend is rising for non-obstetric cause of mortality. Pregnancy is associated with a host of anatomical and physiological alterations that complicate the conduct of anesthesia. The brain is one of the vital organs of the body, and physiological changes during pregnancy alter the anesthesia management if associated with brain pathology. Malignant brain tumors and trauma remain a leading cause of indirect maternal mortality. Review of literature revealed paucity of evidence-based neuroanesthesia management for such patients. Navigating these uncharted waters remains a challenging exercise. With the lack of guidelines, the management is based largely on few case reports or case series.

Management Strategies for Intracranial Pressure Crises in Subarachnoid Hemorrhage

Objectives: Standard management strategies for lowering intracranial pressure (ICP) in traumatic brain injury has been well-studied, but the use of lesser known interventions for ICP in subarachnoid hemorrhage (SAH) remains elusive. Searches were performed in PubMed and EBSCO Host to identify best available evidence for evaluation and management of medically refractory ICP in SAH. The role of standard management strategies such as head elevation, hyperventilation, mannitol and hypertonic saline as well as lesser known management such as sodium bicarbonate, indomethacin, tromethamine, decompressive craniectomy, decompressive laparotomy, hypothermia, and barbiturate coma are reviewed. We also included dose concentrations, dose frequency, infusion volume, and infusion rate for these lesser known strategies. Nonetheless, there is still a gap in the evidence to recommend optimal dosing, timing and its role in the improvement of outcomes but early diagnosis and appropriate management reduce adverse outcomes.

The effect of anesthetic agents on cerebral vasospasms after subarachnoid hemorrhage: A retrospective study

Cerebral vasospasm is the most important cause of morbidity after an aneurysm clipping in the early postoperative period. The aim of this retrospective study was to evaluate whether the incidence of vasospasms differs when using propofol or desflurane for an emergent aneurysm clipping.The data from 102 patients (50 in the propofol group, 52 in the desflurane group) were analyzed. The occurrence of vasospasm based on daily transcranial Doppler, angiography, and cerebral infarction during 14 days after surgery were compared by anesthetic agents. Postoperative data including Glasgow Coma Scale (GCS) score on day 14 after surgery, and the Glasgow Outcome Scale (GOS) score at 3 months were documented.Patients that intraoperatively received propofol for anesthesia maintenance, had higher incidence of transcranial Doppler (TCD)-evident vasospasm than those that received desflurane (54% vs 30.8%, P = .027). The occurrence of TCD-evident vasospasm was still higher (odds ratio: 2.84; 95% confidence interval: 1.12-7.20) in the propofol group than in the desflurane group after adjusting for confounding factors. However, the incidence of angiographic vasospasm, cerebral infarction, and interventions to treat cerebral vasospasms were similar between both groups. GCS score on day 14 after surgery and the GOS score at 3 months were similar between groups.No effect of anesthetic agents on angiographic vasospasm, cerebral infarction, or clinical outcome was observed, whereas desflurane anesthesia was associated with a lower incidence of TCD-evident vasospasms compared to propofol anesthesia. Our study provides a basis for further randomized controlled studies in a larger patient population to clarify the effects of anesthetic agents on the occurrence of cerebral vasospasms.

Intranasal Stem Cell Treatment as a Novel Therapy for Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) represents a major health problem in Western society due to high mortality and morbidity, and the relative young age of patients. Currently, efficacious therapeutic options are very limited. Mesenchymal stem cell (MSC) administration has been shown to improve functional outcome and lesion size in experimental models of stroke and neonatal hypoxic-ischemic brain injury. Here, we studied the therapeutic potential of intranasally administered bone marrow-derived MSCs relatively late postinsult using a rat endovascular puncture model for SAH. Six days after induction of SAH, rats were treated with MSCs or vehicle through nasal administration. Intranasal MSC treatment significantly improved sensorimotor and mechanosensory function at 21 days after SAH. Gray and white matter loss was significantly reduced by MSC treatment and the number of NeuN⁺ neurons around the lesion increased due to MSC treatment. Moreover, intranasal MSC administration led to a sharp decrease in SAH-induced activation of astrocytes and microglia/macrophages in the lesioned hemisphere, especially of M2-like (CD206⁺) microglia/macrophages. Interestingly, MSC administration also decreased SAH-induced depression-like behavior in association with a restoration of tyrosine hydroxylase expression in the substantia nigra and striatum. We show here for the first time that intranasal MSC administration reverses the devastating consequences of SAH, including regeneration of the cerebral lesion, functional recovery, and treatment of comorbid depression-like behavior.

Perioperative Management of Subarachnoid Hemorrhage in a Patient with Alagille Syndrome and Unrepaired Tetralogy of Fallot: Case Report

Alagille syndrome (ALGS) is a genetic disorder associated with multisystem dysfunction involving the hepatic, cardiovascular, and neurologic systems. Tetralogy of Fallot (TOF), a congenital cardiac anomaly, is commonly found in these patients. Patients with ALGS may also have an increased risk of cerebrovascular abnormalities and bleeding. Ruptured cerebral aneurysm and subarachnoid hemorrhage (SAH) may be developed, increasing the incidence of morbidity and mortality. Advances in neuroimaging and neurosurgery have allowed early identification and treatment of such vascular abnormalities, improving patients’ outcomes and reducing life-threatening complications such as intracranial bleeding. Authors describe the perioperative management of a patient with ALGS and TOF who was admitted to the emergency department due a ruptured intracranial aneurysm with concomitant SAH. Surgical treatment included diagnostic cerebral arteriography with coil embolization of a left posterior communicating artery aneurysm, and placement of right external ventricular drain (EVD). The combination of neuroprotective anesthetic techniques, fast emergence from anesthesia, and maintenance of intraoperative hemodynamic stability led to a successful perioperative management. A multidisciplinary approach in specialized centers is essential for the treatment of patients with SAH, especially in patients with ALGS and complex congenital heart disease such as TOF.

Genetic Risk Assessment of Elastin Gene Polymorphisms with Intracranial Aneurysm in Koreans

Elastin encoded by elastin gene (ELN) is a crucial extracellular matrix protein responsible for arterial resilience. The objective of this study was to identify single nucleotide polymorphisms (SNPs) of ELN gene susceptible to intracranial aneurysm (IA) in Korean population. Two SNPs of ELN gene, rs2071307 (Gly422Ser) and rs2856728 (intron), were genotyped in 90 patients with IA and 90 age and frequency matched controls. Fisher’s exact test was conducted to evaluate allelic association with IA. Of the two SNPs in ELN gene, T allele of rs2856728 (intron) showed statistically significant association with increased development of IA (odds ratio [OR]: 2.34, 95% confidence interval [CI]: 1.44–3.81, P = 7.6 × 10⁻⁴). However, G allele of rs2071307 (Gly422Ser) had no significant association with the development of IA (OR: 1.27, 95% CI: 1.44–3.81, P = 0.607). Interestingly, the odds of having rs2856728 variant was approximately 2-fold higher in males than that in females (OR: 3.46 vs. 1.88, P < 0.05). However, none of SNPs showed difference between single and multiple IA in this study. This preliminary study implies that the rs2856728 variant in ELN gene polymorphisms might play crucial roles in the development and pathogenesis of IA in Korean population.

Use of a Minimally Invasive Cardiac Output Monitor to Optimise Haemodynamics in a Patient with Mitral Valve Disease Undergoing Cerebrovascular Surgery

Patients with mitral valve disease undergoing cerebrovascular surgery face increased inherent risks due to their associated cardiac comorbidities. As such, the anaesthetic management of such patients is distinctly challenging. Simultaneous consideration of both the cerebrovascular and underlying cardiac conditions determines key anaesthetic issues, as fluids and vasopressors or inotropes need to be titrated according to haemodynamic variables in order to optimise cerebral blood flow without compromising cardiac function. We report a 45-year-old female patient with mild mitral stenosis and moderate-to-severe mitral regurgitation who presented to the Khoula Hospital, Muscat, Oman, in 2016 following a ruptured anterior communicating artery aneurysm requiring urgent surgical intervention. As highlighted in this case, the VolumeView EV1000™ (Edwards Lifesciences, Irvine, California, USA) system is a minimially invasive haemodynamic monitor that can help immensely in the perioperative management of such patients.

Propofol inhibits invasion and proliferation of C6 glioma cells by regulating the Ca2+ permeable AMPA receptor-system xc- pathway

Anesthetics are documented to affect tumors; therefore, we studied the antiglioma effect of propofol on proliferation and invasiveness of glioma cells and explored the underlying mechanism. C6 glioma cells were cultured and treated with propofol, and cell viability, invasiveness, and migration were measured. Glutamate release was measured using an enzyme-catalyzed kinetic reaction. xCT protein and α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor GluR2 subunit protein expression was assessed with Western blot analysis and immunofluorescent staining. We observed that propofol significantly inhibited C6 glioma cell viability, invasiveness, and migration and decreased glutamate release. An agonist of the cystine/glutamate antiporter system (system x_c^-), N-acetylcysteine (NAC), reversed propofol's effects, and propofol could inhibit C6 glioma cell proliferation by adding excess exogenous glutamate (100μM). Finally, propofol increased the surface expression of GluR2, but decreased surface expression of xCT. The effects of propofol on surface expression of GluR2 and xCT could be rescued by (R, S)-AMPA, an agonist of Ca²⁺ permeable AMPA receptor (CPAR). Thus, propofol can inhibit cell viability, invasiveness, and migration of C6 glioma cells, and the CPAR-system x_c^- pathway contributes to these events.

Lidocaine as an Induction Agent for Intracranial Aneurysm Surgery: A Case Series

Introduction:

Induction of anaesthesia and its associated spikes in blood pressure can cause rupture of an aneurysm during intracranial surgery. Lidocaine can reportedly provide hemodynamic stability when applied before endotracheal intubation. Rapid injection of large doses of lidocaine can cause unconsciousness.

Case Presentation:

Lidocaine was applied as the sole anaesthetic for induction and maintenance during aneurysm surgery in four patients undergoing intracranial aneurysm surgery. Blood pressure alteration after induction and during surgery, bleeding, brain laxity, intracranial pressure and extubation time were acceptable.

Conclusions:

Although propofol remains a standard agent for such types of surgeries, lidocaine proved equally effective and coupled with its low cost, minimal side effects and omission of other hypnotic agents was a plausible induction agent and a maintenance drug in the selected cases.

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.

Principles of neuroanesthesia in aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage is associated with high mortality. Understanding of the underlying pathophysiology is important as early intervention can improve outcome. Increasing age, altered sensorium and poor Hunt and Hess grade are independent predictors of adverse outcome. Early operative interventions imposes an onus on anesthesiologists to provide brain relaxation. Coiling and clipping are the two treatment options with increasing trends toward coiling. Intraoperatively, tight control of blood pressure and adequate brain relaxation is desirable, so that accidental aneurysm rupture can be averted. Patients with poor grades tolerate higher blood pressures, but are prone to ischemia whereas patients with lower grades tolerate lower blood pressure, but are prone to aneurysm rupture if blood pressure increases. Patients with Hunt and Hess Grade I or II with uneventful intraoperative course are extubated in operation theater, whereas, higher grades are kept electively ventilated. Postoperative management includes attention toward fluid status and early management of vasospasm.

Ventricular pacing for induced hypotension in a toddler

Cerebral aneurysm clipping may require periods of hypotension to facilitate dissection and clip application. We describe the use of rapid ventricular pacing to facilitate establishment of controlled hypotension for an 18-month-old child during clipping for giant basilar artery aneurysm. This technique is an alternative to pharmacologic means of inducing hypotension for neurosurgical procedures and has not been previously described in children.

The harmful effects of subarachnoid hemorrhage on extracerebral organs

Subarachnoid hemorrhage (SAH) is a devastating neurological disorder. Patients with aneurysmal SAH develop secondary complications that are important causes of morbidity and mortality. Aside from secondary neurological injuries, SAH has been associated with nonneurologic medical complications, such as neurocardiogenic injury, neurogenic pulmonary edema, hyperglycemia, and electrolyte imbalance, of which cardiac and pulmonary complications are most common. The related mechanisms include activation of the sympathetic nervous system, release of catecholamines and other hormones, and inflammatory responses. Extracerebral complications are directly related to the severity of SAH-induced brain injury and indicate the clinical outcome in patients. This review provides an overview of the extracerebral complications after SAH. We also aim to describe the manifestations, underlying mechanisms, and the effects of those extracerebral complications on outcome following SAH.

Controversies in the anesthetic management of intraoperative rupture of intracranial aneurysm

Despite great advancements in the management of aneurysmal subarachnoid hemorrhage (SAH), outcomes following SAH rupture have remained relatively unchanged. In addition, little data exists to guide the anesthetic management of intraoperative aneurysm rupture (IAR), though intraoperative management may have a significant effect on overall neurological outcomes. This review highlights the various controversies related to different anesthetic management related to aneurysm rupture. The first controversy relates to management of preexisting factors that affect risk of IAR. The second controversy relates to diagnostic techniques, particularly neurophysiological monitoring. The third controversy pertains to hemodynamic goals. The neuroprotective effects of various factors, including hypothermia, various anesthetic/pharmacologic agents, and burst suppression, remain poorly understood and have yet to be further elucidated. Different management strategies for IAR during aneurysmal clipping versus coiling also need further attention.

The rodent endovascular puncture model of subarachnoid hemorrhage: mechanisms of brain damage and therapeutic strategies

Subarachnoid hemorrhage (SAH) represents a considerable health problem. To date, limited therapeutic options are available. In order to develop effective therapeutic strategies for SAH, the mechanisms involved in SAH brain damage should be fully explored. Here we review the mechanisms of SAH brain damage induced by the experimental endovascular puncture model. We have included a description of similarities and distinctions between experimental SAH in animals and human SAH pathology. Moreover, several novel treatment options to diminish SAH brain damage are discussed.SAH is accompanied by cerebral inflammation as demonstrated by an influx of inflammatory cells into the cerebral parenchyma, upregulation of inflammatory transcriptional pathways and increased expression of cytokines and chemokines. Additionally, various cell death pathways including cerebral apoptosis, necrosis, necroptosis and autophagy are involved in neuronal damage caused by SAH.Treatment strategies aiming at inhibition of inflammatory or cell death pathways demonstrate the importance of these mechanisms for survival after experimental SAH. Moreover, neuroregenerative therapies using stem cells are discussed as a possible strategy to repair the brain after SAH since this therapy may extend the window of treatment considerably. We propose the endovascular puncture model as a suitable animal model which resembles the human pathology of SAH and which could be applied to investigate novel therapeutic therapies to combat this debilitating insult.

[Aneurysmal subarachnoid hemorrhage]

Acute subarachnoid hemorrhage (SAH) is a severe and acute life-threatening cerebrovascular disease. Approximately 80% of all acute non-traumatic SAHs are the result of a ruptured cerebrovascular aneurysm. Despite advances in diagnosis and treatment a high morbidity and mortality still exists. Apart from the primary cerebral damage there are also secondary complications, such as vasospasm, rebleeding, hydrocephalus, cerebral edema or hydrocephalus. For an appropriate therapy an understanding of the extensive pathophysiology, the options in diagnostics and therapy and the complications of the disease are essential. Anesthesiologists are decisively involved in the therapy of the primary and secondary damages and subsequently in the outcome as well. This article provides an overview of the perioperative and intensive care management of patients with SAH.

Systematic silencing of benzylisoquinoline alkaloid biosynthetic genes reveals the major route to papaverine in opium poppy

Papaverine, a major benzylisoquinoline alkaloid in opium poppy (Papaver somniferum), is used as a vasodilator and antispasmodic. Conversion of the initial intermediate (S)-norcoclaurine to papaverine involves 3'-hydroxylation, four O-methylations and dehydrogenation. However, our understanding of papaverine biosynthesis remains controversial more than a century after an initial scheme was proposed. In vitro assays and in vivo labeling studies have been insufficient to establish the sequence of conversions, the potential role of the intermediate (S)-reticuline, and the enzymes involved. We used virus-induced gene silencing in opium poppy to individually suppress the expression of six genes with putative roles in papaverine biosynthesis. Suppression of the gene encoding coclaurine N-methyltransferase dramatically increased papaverine levels at the expense of N-methylated alkaloids, indicating that the main biosynthetic route to papaverine proceeds via N-desmethylated compounds rather than through (S)-reticuline. Suppression of genes encoding (S)-3'-hydroxy-N-methylcoclaurine 4-O-methyltransferase and norreticuline 7-O-methyltransferase, which accept certain N-desmethylated alkaloids, reduced papaverine content. In contrast, suppression of genes encoding N-methylcoclaurine 3'-hydroxylase or reticuline 7-O-methyltransferase, which are specific for N-methylated alkaloids, did not affect papaverine levels. Suppression of norcoclaurine 6-O-methyltransferase transcript levels significantly suppressed total alkaloid accumulation, implicating (S)-coclaurine as a key branch-point intermediate. The differential detection of N-desmethylated compounds in response to suppression of specific genes highlights the primary route to papaverine.

Assaying embryotoxicity in the test tube: current limitations of the embryonic stem cell test (EST) challenging its applicability domain

Testing for embryotoxicity in vitro is an attractive alternative to animal experimentation. The embryonic stem cell test (EST) is such a method, and it has been formally validated by the European Centre for the Validation of Alternative Methods. A number of recent studies have underscored the potential of this method. However, the EST performed well below the 78% accuracy expected from the validation study using a new set of chemicals and pharmaceutical compounds, and also of toxicity criteria, tested to enlarge the database of the validated EST as part of the Work Package III of the ReProTect Project funded within the 6th Framework Programme of the European Union. To assess the performance and applicability domain of the EST we present a detailed review of the substances and their effects in the EST being nitrofen, ochratoxin A, D-penicillamine, methylazoxymethanol, lovastatin, papaverine, warfarin, β-aminopropionitrile, dinoseb, furosemide, doxylamine, pravastatin, and metoclopramide. By delineation of the molecular mechanisms of the substances we identify six categories of reasons for misclassifications. Some of these limitations might also affect other in vitro methods assessing embryotoxicity. Substances that fall into these categories need to be included in future validation sets and in validation guidelines for embryotoxicity testing. Most importantly, we suggest conceivable improvements and additions to the EST which will resolve most of the limitations.

Propofol post-conditioning induced long-term neuroprotection and reduced internalization of AMPAR GluR2 subunit in a rat model of focal cerebral ischemia/reperfusion

We previously reported that propofol (20 mg/kg/h) post-conditioning provided acute (up to 24 h) neuroprotection in rats with transient middle cerebral artery occlusion. In this study, we extend these data by examining long-term protection and exploring underlying mechanisms involving AMPA receptor GluR2 subunit internalization. Rats were treated with propofol 20 mg/kg/h after 60 min of occlusion (beginning of reperfusion for 4 h). Propofol post-conditioning reduced infarct volume and improved spatial memory deficiencies (up to 28 days) induced by ischemia/reperfusion injury. Additionally, Propofol post-conditioning promoted neurogenesis in the dentate gyrus of hippocampus, as measured by bromodeoxyuridine and neuron-specific nuclear protein immunofluorescence-double staining at day 28 after reperfusion. Finally, propofol post-conditioning increased the surface expression of AMPA receptor GluR2 subunit, thus inhibited the internalization of this part until 28 days after stroke. In conclusion, our data suggest that propofol post-conditioning provides long-term protection against focal cerebral ischemia/reperfusion injury in rats. Furthermore, we found that the inhibition of AMPA receptor GluR2 subunit internalization may contributed to this long-term neuroprotection.

[Protective measures against cerebral ischemia following subarachnoid hemorrhage: Part 1]

BACKGROUND AND OBJECTIVES

Cerebral vasospasm following aneurysmal subarachnoid hemorrhage contributes significantly to morbidity and mortality. Many studies on the various treatments aimed at preventing cerebral vasospasm have been carried out, but evidence of efficacy is limited. Our aim was to review the literature on the various therapies for which there is scientific evidence of protection against cerebral vasospasm following aneurysmal subarachnoid hemorrhage.

METHODS

MEDLINE search (1950 to the october 2009) and review of articles found on the prevention of cerebral vasospasm following aneurysmal subarachnoid hemorrhage. The search was restricted to articles in English, French, and Spanish. The keywords were cerebral vasospasm, subarachnoid hemorrhage, therapy, nimodipine, triple H, clazosentan, statins, and magnesium in addition to the word forms derived from them. We also searched manually for references cited in the selected articles. A title was included if it was a randomized controlled trial, meta-analysis, nonrandomized clinical trial, descriptive study, observational study with statistical analysis, opinion article, or expert review.

RESULTS

Part 1 analyzed treatment with calcium antagonists and triple-H therapy (hypertension, hemodilution, and hypervolemia). Part 2 analyzed new therapies such as clazosentan, magnesium, and statins. A total of 597 titles were located; 283 were initially selected. The 61 articles finally selected for review were of the following types: 2 opinion articles, 21 randomized controlled trials, 22 expert review articles, 3 meta-analyses, 4 nonrandomized clinical trials, 1 descriptive study, and 5 observational studies with statistical analysis. Three studies (2 meta-analyses and 1 randomized controlled trial) demonstrated that nimodipine use confers benefits (reduced morbidity and mortality) for patients with aneurysmatic subarachnoid hemorrhage. Statistically significant clinical benefits could not be demonstrated for the other drugs (clazosentan, statins, and magnesium).

CONCLUSIONS

Insufficient evidence is available to support the use of the triple-H therapy, clazosentan, statins, or magnesium sulfate for the prevention of cerebral vasospasm following subarachnoid hemorrhage. Nimodipine is the only preventative treatment that can be recommended.

Performance of cardiac output measurement derived from arterial pressure waveform analysis in patients requiring high-dose vasopressor therapy

BACKGROUND

Arterial pressure waveform analysis of cardiac output (APCO) without external calibration (FloTrac/Vigileo™) is critically dependent upon computation of vascular tone that has necessitated several refinements of the underlying software algorithms. We hypothesized that changes in vascular tone induced by high-dose vasopressor therapy affect the accuracy of APCO measurements independently of the FloTrac software version.

METHODS

In this prospective observational study, we assessed the validity of uncalibrated APCO measurements compared with transpulmonary thermodilution cardiac output (TPCO) measurements in 24 patients undergoing vasopressor therapy for the treatment of cerebral vasospasm after subarachnoid haemorrhage.

RESULTS

Patients received vasoactive support with [mean (sd)] 0.53 (0.46) µg kg(-1) min(-1) norepinephrine resulting in mean arterial pressure of 104 (14) mm Hg and mean systemic vascular resistance of 943 (248) dyn s(-1) cm(-5). Cardiac output (CO) data pairs (158) were obtained simultaneously by APCO and TPCO measurements. TPCO ranged from 5.2 to 14.3 litre min(-1), and APCO from 4.1 to 13.7 litre min(-1). Bias and limits of agreement were 0.9 and 2.5 litre min(-1), resulting in an overall percentage error of 29.6% for 68 data pairs analysed with the second-generation FloTrac(®) software and 27.9% for 90 data pairs analysed with the third-generation software. Precision of the reference technique was 2.6%, while APCO measurements yielded a precision of 29.5% and 27.9% for the second- and the third-generation software, respectively. For both software versions, bias (TPCO-APCO) correlated inversely with systemic vascular resistance.

CONCLUSIONS

In neurosurgical patients requiring high-dose vasopressor support, precision of uncalibrated CO measurements depended on systemic vascular resistance. Introduction of the third software algorithm did not improve the insufficient precision (>20%) for APCO measurements observed with the second software version.