Oral glutamine supplementation increases seizure severity in a rodent model of mesial temporal lobe epilepsy.

Background: Glutamine synthetase (GS) is the only enzyme known to synthesize significant amounts of glutamine in mammals, and loss of GS in the hippocampus has been implicated in the pathophysiology of medication refractory mesial temporal lobe epilepsy (MTLE). Moreover, loss-of-function mutations of the GS gene causes severe epileptic encephalopathy, and supplementation with glutamine has been shown to normalize EEG and possibly improve the outcome in these patients. Here we examined whether oral glutamine supplementation is an effective treatment for MTLE by assessing the frequency and severity of seizures after supplementation in a translationally relevant model of the disease.Methods: Male Sprague Dawley rats (380-400 g) were allowed to drink unlimited amounts of glutamine in water (3.6% w/v; n = 8) or pure water (n = 8) for several weeks. Ten days after the start of glutamine supplementation, GS was chronically inhibited in the hippocampus to induce MTLE. Continuous video-intracranial EEG was collected for 21 days to determine the frequency and severity of seizures.Results: While there was no change in seizure frequency between the groups, the proportion of convulsive seizures was significantly higher in glutamine treated animals during the first three days of GS inhibition.Conclusion: The results suggest that oral glutamine supplementation transiently increases seizure severity in the initial stages of an epilepsy model, indicating a potential role of the amino acid in seizure propagation and epileptogenesis.

Absence seizures and their relationship to depression and anxiety: Evidence for bidirectionality.

Absence seizures (AS), presenting as short losses of consciousness with staring spells, are a common manifestation of childhood epilepsy that is associated with behavioral, emotional, and social impairments. It has also been suggested that patients with AS are more likely to suffer from mood disorders such as depression and anxiety. This systematic review and meta-analysis synthesizes human and animal models that investigated mood disorders and AS. Of the 1019 scientific publications identified, 35 articles met the inclusion criteria for this review. We found that patients with AS had greater odds of developing depression and anxiety when compared to controls (odds ratio = 4.93, 95% confidence interval = 2.91-8.35, p < .01). The included studies further suggest a strong correlation between AS and depression and anxiety in the form of a bidirectional relationship. The current literature emphasizes that these conditions likely share underlying mechanisms, such as genetic predisposition, neurophysiology, and anatomical pathways. Further research will clarify this relationship and ensure more effective treatment for AS and mood disorders.

Increased branched-chain amino acids at baseline and hours before a spontaneous seizure in the human epileptic brain.

The objective of this study was to monitor the extracellular brain chemistry dynamics at baseline and in relation to spontaneous seizures in human patients with refractory epilepsy. Thirty patients with drug-resistant focal epilepsy underwent intracranial electroencephalography and concurrent brain microdialysis for up to 8 continuous days. Extracellular brain glutamate, glutamine, and the branched-chain amino acids (BCAAs) valine, leucine, and isoleucine were quantified in the dialysis samples by liquid chromatography-tandem mass spectrometry. Extracellular BCAAs and glutamate were chronically elevated at baseline by approximately 1.5-3-fold in brain regions of seizure onset and propagation versus regions not involved by seizures. Moreover, isoleucine increased significantly above baseline as early as 3 h before a spontaneous seizure. BCAAs play important roles in glutamatergic neurotransmission, mitochondrial function, neurodegeneration, and mammalian target of rapamycin signaling. Because all of these processes have been implicated in epilepsy, the results suggest a novel role of BCAAs in the pathogenesis of spontaneous seizures.

Spinal versus general anesthesia for minimally invasive transforaminal lumbar interbody fusion: implications on operating room time, pain, and ambulation.

OBJECTIVE: There has been increasing interest in the use of spinal anesthesia (SA) for spine surgery, especially within Enhanced Recovery After Surgery (ERAS) protocols. Despite the wide adoption of SA by the orthopedic practices, it has not gained wide acceptance in lumbar spine surgery. Studies investigating SA versus general anesthesia (GA) in lumbar laminectomy and discectomy have found that SA reduces perioperative costs and leads to a reduction in analgesic use, as well as to shorter anesthesia and surgery time. The aim of this retrospective, case-control study was to compare the perioperative outcomes of patients who underwent minimally invasive surgery (MIS)-transforaminal lumbar interbody fusion (TLIF) after administration of SA with those who underwent MIS-TLIF under GA. METHODS: Overall, 40 consecutive patients who underwent MIS-TLIF by a single surgeon were analyzed; 20 patients received SA and 20 patients received GA. Procedure time, intraoperative adverse events, postoperative adverse events, postoperative length of stay, 3-hour postanesthesia care unit (PACU) numeric rating scale (NRS) pain score, opioid medication, and time to first ambulation were collected for each patient. RESULTS: The two groups were homogeneous for clinical characteristics. A decrease in total operating room (OR) time was found for patients who underwent MIS-TLIF after administration of SA, with a mean OR time of 156.5 ± 18.9 minutes versus 213.6 ± 47.4 minutes for patients who underwent MIS-TLIF under GA (p < 0.0001), a reduction of 27%. A decrease in total procedure time was also observed for SA versus GA (122 ± 16.7 minutes vs 175.2 ± 10 minutes; p < 0.0001). No significant differences were found in intraoperative and postoperative adverse events. There was a difference in the mean maximum NRS pain score during the first 3 hours in the PACU as patients who received SA reported a lower pain score compared with those who received GA (4.8 ± 3.5 vs 7.3 ± 2.7; p = 0.018). No significant difference was observed in morphine equivalents received by the two groups. A difference was also observed in the mean overall NRS pain score, with 2.4 ± 2.1 for the SA group versus 4.9 ± 2.3 for the GA group (p = 0.001). Patients who received SA had a shorter time to first ambulation compared with those who received GA (385.8 ± 353.8 minutes vs 855.9 ± 337.4 minutes; p < 0.0001). CONCLUSIONS: The results of this study have pointed to some important observations in this patient population. SA offers unique advantages in comparison with GA for performing MIS-TLIF, including reduced OR time and postoperative pain, and faster postoperative mobilization.

Neurophysiological monitoring during neurosurgery: anesthetic considerations based on outcome evidence.

PURPOSE OF REVIEW: This article reviews the recent outcome studies that investigated intraoperative neurophysiological monitoring (IONM) during spine, neurovascular and brain tumor surgery. RECENT FINDINGS: Several recent studies have focused on identifying which types of neurosurgical procedures might benefit most from IONM use. Despite conflicting literature regarding its efficacy in improving neurological outcomes, many experts have advocated for the use of IONM in neurosurgery. Several themes have emerged from the recent literature: the entire perioperative team must always work together to ensure adequate communication and intervention; systems and checklists, in which each member of the perioperative team has a clearly defined role, can be useful in the event of a sudden intraoperative changes in electrophysiological signals; regardless of the IONM modality used, any sudden change in electrophysiological signal should prompt an immediate and appropriate intervention; a multimodal IONM approach is often, but not always, advantageous over a single IONM approach. SUMMARY: For neurosurgical procedures that can be complicated by neural injury, the use of IONM should be considered according to specific patient and surgical factors. Future studies should focus on improving IONM technology and optimizing sensitivity and specificity for detecting any impending neural damage.

Multidrug Resistance Acinetobacter Bacteremia Secondary to Ventilator-Associated Pneumonia: Risk Factors and Outcome.

PURPOSE: Acinetobacter baumannii is a multidrug resistant (MDR), gram-negative bacterium commonly implicated in ventilator-associated pneumonia (VAP) in critically ill patients. Patients in the intensive care unit (ICU) with VAP often subsequently develop A baumannii bacteremia, which may significantly worsen outcomes. MATERIALS AND METHODS: In this study, we retrospectively reviewed the clinical and laboratory records of 129 ICU patients spanning 6 years with MDR A baumannii VAP; 46 (35%) of these patients had concomitant MDR A baumannii bacteremia. RESULTS: The ICU mortality rate was higher in patients with VAP having A baumannii bacteremia compared to nonbacteremic patients (32.4% vs 9.6% respectively, P < .005). Age >65 years, an Acute Physiology and Chronic Health Evaluation II (APACHE-II) score higher than 20, a Sequential Organ Failure Assessment (SOFA) score higher than 7 on the day of bacteremia, and the presence of comorbid disease (chronic obstructive pulmonary disease [COPD] and chronic renal failure) were found to be independent risk factors for in-hospital mortality in this population. Multidrug resistant A baumannii was not an independent risk factor for mortality. CONCLUSION: Although the presence of comorbid diseases (COPD and chronic renal failure) and severity of disease (APACHE > 20 and SOFA >7) were found to be independent risk factors for ICU mortality, MDR A baumannii bacteremia was not an independent risk factor for mortality in our critically ill population.

Severe Intraoperative Hyperglycemia Is Independently Associated With Postoperative Composite Infection After Craniotomy: An Observational Study.

BACKGROUND: Postoperative infection after craniotomy carries an increased risk of morbidity and mortality. Identification and correction of the risk factors should be prioritized. The association of intraoperative hyperglycemia with postoperative infections in patients undergoing craniotomy is inadequately studied. METHODS: A total of 224 patients were prospectively enrolled in 2 major medical centers to assess whether severe intraoperative hyperglycemia (SIH, blood glucose ≥180 mg/dL) is associated with an increased risk of postoperative infection in patients undergoing craniotomy. Arterial blood samples were drawn and analyzed immediately after anesthetic induction and again before tracheal extubation. The new onset of any type of infection within 7 days after craniotomy was determined. RESULTS: The incidence of new postoperative composite infection was 10% (n = 22) within the first week after craniotomy. Weight, sex, American Society of Anesthesiologists score, preoperative and/or intraoperative steroid use, and diabetes mellitus were not associated with postoperative infection. SIH was independently associated with postoperative infection (odds ratio [95% confidence interval], 4.17 [1.50-11.56], P = .006) after fitting a multiple logistic regression model to adjust for emergency surgery, length of surgery, and age ≥65 years. CONCLUSIONS: SIH is independently associated with postoperative new-onset composite infections in patients undergoing craniotomy. Whether prevention of SIH during craniotomy results in a reduced postoperative risk of infection is unknown and needs to be appraised by further study.

Neurotoxicity of anesthetic drugs: an update.

PURPOSE OF REVIEW: This article reviews the most recently published evidence that investigated anesthesia-induced neurotoxicity in both animals and humans, especially as it pertains to the perinatal period. RECENT FINDINGS: Several recent studies have focused on better understanding the complex mechanisms that underlie intravenous and volatile anesthesia-induced neurotoxicity in animals. Adjuvant agents that target these pathways have been investigated for their effectiveness in attenuating the neuroapoptosis and neurocognitive deficits that result from anesthesia exposure, including dexmedetomidine, rutin, vitamin C, tumor necrosis factor α, lithium, apocynin, carreic acid phenethyl ester. Five clinical studies, including one randomized control trial, provided inconsistent evidence on anesthesia-induced neurotoxicity in humans. SUMMARY: Despite a growing body of preclinical studies that have demonstrated anesthesia-induced neurotoxic effects in the developing and aging brain, their effects on the human brain remains to be determined. The performance of large-scale human studies is limited by several important factors, and noninvasive biomarkers and neuroimaging modalities should be employed to define the injury phenotypes that reflect anesthesia-induced neurotoxicity. Ultimately, the use of these modalities may provide new insights into whether the concerns of anesthetics are justified in humans.

Recent trends in the anesthetic management of craniotomy for supratentorial tumor resection.

PURPOSE OF REVIEW: The article reviews the recent evidence on the anesthetic management of patients undergoing craniotomy for supratentorial tumor resection. RECENT FINDINGS: A rapid recovery of neurological function after craniotomy for supratentorial tumor allows for the prompt diagnosis of intracranial complications and possibly an early hospital discharge. Intraoperative esmolol infusion was shown to reduce the anesthetic requirements, and may facilitate a more rapid recovery of neurological function. Outpatient craniotomy for supratentorial tumor resection has been associated with several clinical and economic benefits, but has not gained widespread use because of skepticism and medical-legal concerns. Awake craniotomy is associated with advantageous outcomes compared with surgery under general anesthesia, and is regarded as the standard of care for tumors that reside in or in close proximity to the eloquent brain. Recent studies have demonstrated that intraoperative electroacupuncture, dexmedetomidine, pregabalin, and lidocaine may facilitate postcraniotomy pain management. The use of volatile anesthetic agents in cancer surgery is associated with a worse survival compared with intravenous anesthetics, possibly by hindering immunologic defenses against cancer cells. SUMMARY: Recent evidence has yielded valuable information regarding anesthetic management of patients undergoing supratentorial tumor craniotomy. Despite a plethora of studies that compare short-term outcomes using different anesthetic and analgesic regimens, randomized controlled trials that examine the long-term outcomes (i.e., neurocognitive function, quality of life, tumor recurrence, and survival) that are of particular interest to patients are needed.

Inhibition of glutamine synthetase in the central nucleus of the amygdala induces anhedonic behavior and recurrent seizures in a rat model of mesial temporal lobe epilepsy.

The prevalence of depression and suicide is increased in patients with mesial temporal lobe epilepsy (MTLE); however, the underlying mechanism remains unknown. Anhedonia, a core symptom of depression that is predictive of suicide, is common in patients with MTLE. Glutamine synthetase, an astrocytic enzyme that metabolizes glutamate and ammonia to glutamine, is reduced in the amygdala in patients with epilepsy and depression and in suicide victims. Here, we sought to develop a novel model of anhedonia in MTLE by testing the hypothesis that deficiency in glutamine synthetase in the central nucleus of the amygdala (CeA) leads to epilepsy and comorbid anhedonia. Nineteen male Sprague-Dawley rats were implanted with an osmotic pump infusing either the glutamine synthetase inhibitor methionine sulfoximine [MSO (n=12)] or phosphate buffered saline [PBS (n=7)] into the right CeA. Seizure activity was monitored by video-intracranial electroencephalogram (EEG) recordings for 21days after the onset of MSO infusion. Sucrose preference, a measure of anhedonia, was assessed after 21days. Methionine sulfoximine-infused rats exhibited recurrent seizures during the monitoring period and showed decreased sucrose preference over days when compared with PBS-infused rats (p<0.01). Water consumption did not differ between the PBS-treated group and the MSO-treated group. Neurons were lost in the CeA, but not the medial amygdala, lateral amygdala, basolateral amygdala, or the hilus of the dentate gyrus, in the MSO-treated rats. The results suggest that decreased glutamine synthetase activity in the CeA is a possible common cause of anhedonia and seizures in TLE. We propose that the MSO CeA model can be used for mechanistic studies that will lead to the development and testing of novel drugs to prevent seizures, depression, and suicide in patients with TLE.

Anesthetic Management of Patients with Congenital Insensitivity to Pain with Anhidrosis: A Retrospective Analysis of 358 Procedures Performed Under General Anesthesia.

BACKGROUND: Congenital insensitivity to pain with anhidrosis (CIPA) is a rare autosomal recessive disorder characterized by recurrent episodic fevers, anhidrosis, absent reaction to noxious stimuli, self-mutilating behavior, and mental retardation. The anesthetic management of patients with CIPA is challenging. Autonomic nervous system abnormalities are common, and patients are at increased risk for perioperative complications. METHODS: In this study, we describe our experience with 35 patients with CIPA who underwent 358 procedures requiring general anesthesia between 1990 and 2013. RESULTS: During surgery, 3 patients developed hyperthermia intraoperatively (>37.5°C) without prior fever. There were no cases of intraoperative hyperpyrexia (>40°C). Aspiration was suspected in 2 patients, and in another patient aspiration was prevented by the use of endotracheal tube, early detection of regurgitation, and aggressive suctioning. One patient had cardiac arrest requiring cardiopulmonary resuscitation. Intraoperative bradycardia was observed in 10 cases, and postoperative bradycardia was observed in 11 cases. CONCLUSIONS: Regurgitation, hyperthermia, and aspiration were uncommon, but the incidence of bradycardia was higher than has been reported in previous studies. CIPA remains a challenge for anesthesiologists. Because of the rare nature of this disorder, the risk of various complications is difficult to predict.

Cerebral protection during neurosurgery and stroke.

PURPOSE OF REVIEW: This article reviews the recent evidence on perioperative neuroprotection in patients undergoing brain surgery and in patients with acute stroke. RECENT FINDINGS: With varying degrees of success, numerous pharmacological and nonpharmacological therapies have been employed to provide neuroprotection for patients during the perioperative period and after acute ischemic stroke (IAS). Recent studies have failed to demonstrate neuroprotective effects of intraoperative remifentanil or propofol use, although hypertonic saline may provide better brain relaxation than mannitol during elective intracranial surgery for tumor. Magnesium sulfate offers no improvement in neurological outcome at 90 days after stroke. Medical management alone may be superior to medical management with interventional therapy for the prevention of death or stroke in unruptured arteriovenous malformations. In patients with IAS with a proximal vessel occlusion, small infarct core, and moderate-to-good collateral circulation, rapid endovascular treatment resulted in improved functional outcomes and reduced mortality. For endovascular clot evacuation after IAS, conscious sedation may be safer than general anaesthesia. SUMMARY: Recent evidence provides insufficient evidence of neuroprotective strategies to guide clinical management, and more randomized clinical trials are needed to optimize patient care.

Anaesthesia for deep brain stimulation: a review.

PURPOSE OF REVIEW: Deep brain stimulation (DBS) is a well tolerated and efficacious surgical treatment for movement disorders, chronic pain, psychiatric disorder, and a growing number of neurological disorders. Given that the brain targets are deep and small, accurate electrode placement is commonly accomplished by utilizing frame-based systems. DBS electrode placement is confirmed by microlectrode recordings and macrostimulation to optimize and verify target placement. With a reliance on electrophysiology, proper anaesthetic management is paramount to balance patient comfort without interfering with neurophysiology. RECENT FINDINGS: To achieve optimal pain control, generous amounts of local anaesthesia are instilled into the planned incision. During the opening and closing states, conscious sedation is the prevailing method of anaesthesia. The preferred agents are dexmedetomidine, propofol, and remifentanil, as they affect neurocognitive testing the least, and shorter acting. All the agents are turned off 15-30 min prior to microelectrode recording. Dexmedetomidine has gained popularity in DBS procedures, but has some considerations at higher doses. The addition of ketamine is helpful for pediatric cases. SUMMARY: DBS is a robust surgical treatment for a variety of neurological disorders. Appropriate anaesthetic agents that achieve patient comfort without interfering with electrophysiology are paramount.

5-aminovaleric acid suppresses the development of severe seizures in the methionine sulfoximine model of mesial temporal lobe epilepsy.

Mesial temporal lobe epilepsy (MTLE) is one of the most common forms of drug-resistant, localization-related epilepsies in humans. One potential therapeutic target is the brain glutamine-glutamate-GABA metabolic pathway, which is perturbed in patients with MTLE. Loss of glutamine synthetase (GS) in astrocytes may be critically involved in this perturbation, which can be modeled by infusing the GS inhibitor methionine sulfoximine (MSO) into the entorhinal-hippocampal area in rats. Because 5-aminovaleric acid (5-AV) has been implicated in modulation of the glutamine-glutamate-GABA metabolic pathway, we hypothesized that 5-AV would alter the expression of seizures in the MSO model of MTLE. Male Sprague Dawley rats (300-330g) were implanted with an Alzet pump placed subcutaneously in the abdominal region to release either 5-AV (0.05mg/mL, n=6) or phosphate buffered saline (PBS, n=6) at a rate of 2.5µl/h over 28days. Five to 7days after surgery, all rats were implanted with an intracranial pump infusing MSO (2.5mg/mL; 0.25µl/h) unilaterally into the hippocampal formation. Following the second surgery, intracranial EEG was measured from the left and right hemispheres above the dorsal hippocampal formations for a continuous period of 21days. The EEG was correlated with simultaneous video recordings to determine the stage of seizures according to a modified Racine scale. Five-AV-treated rats experienced a 3.5 fold reduction in the number of seizures (6.7±1.4seizures/day) than PBS-treated rats (23.2±6.3seizures/day) during the first 2days following MSO pump placement (p<0.005). Both groups showed similar seizure frequency over days 3-21 (~1seizure/day). However, the fraction of the most severe type of seizures (Racine stages 4 and 5) increased over time in the PBS treated group, but not in the 5-AV treated group. Notably, 5-AV treated rats experienced a 2.3 and 2.6 fold lower fraction of stage 4 and 5 seizures than PBS-treated rats during the 2nd and 3rd weeks of MSO treatment respectively (p<0 .05 and p<0.001 respective to week). Five-AV markedly reduces the number of seizures initially and suppresses the development of the most severe type of seizures in the MSO model of MTLE. These results may have implications for the therapeutic use of 5-AV in treating mesial temporal lobe seizures and for our understanding of the chemical pathology of epileptogenesis and MTLE.

Brain to blood glutamate scavenging as a novel therapeutic modality: a review.

It is well known that abnormally elevated glutamate levels in the brain are associated with secondary brain injury following acute and chronic brain insults. As such, a tight regulation of brain glutamate concentrations is of utmost importance in preventing the neurodegenerative effects of excess glutamate. There has been much effort in recent years to better understand the mechanisms by which glutamate is reduced in the brain to non-toxic concentrations, and in how to safely accelerate these mechanisms. Blood glutamate scavengers such as oxaloacetate, pyruvate, glutamate-oxaloacetate transaminase, and glutamate-pyruvate transaminase have been shown to reduce blood glutamate concentrations, thereby increasing the driving force of the brain to blood glutamate efflux and subsequently reducing brain glutamate levels. In the past decade, blood glutamate scavengers have gained increasing international interest, and its uses have been applied to a wide range of experimental contexts in animal models of traumatic brain injury, ischemic stroke, subarachnoid hemorrhage, epilepsy, migraine, and malignant gliomas. Although glutamate scavengers have not yet been used in humans, there is increasing evidence that their use may provide effective and exciting new therapeutic modalities. Here, we review the laboratory evidence for the use of blood glutamate scavengers. Other experimental neuroprotective treatments thought to scavenge blood glutamate, including estrogen and progesterone, beta-adrenergic activation, hypothermia, insulin and glucagon, and hemodialysis and peritoneal dialysis are also discussed. The evidence reviewed here will hopefully pave the way for future clinical trials.

Comparison of the effectiveness of high flow nasal oxygen cannula vs. standard non-rebreather oxygen face mask in post-extubation intensive care unit patients.

BACKGROUND: Optimal oxygen supply is the cornerstone of the management of critically ill patients after extubation, especially in patients at high risk for extubation failure. In recent years, high flow oxygen system devices have offered an appropriate alternative to standard oxygen therapy devices such as conventional face masks and nasal prongs. OBJECTIVES: To assess the clinical effects of high flow nasal cannula (HFNC) compared with standard oxygen face masks in Intensive Care Unit (ICU) patients after extubation. METHODS: We retrospectively analyzed 67 consecutive ventilated critical care patients in the ICU over a period of 1 year. The patients were allocated to two treatment groups: HFNC (34 patients, group 1) and non-rebreathing oxygen face mask (NRB) (33 patients, group 2). Vital respiratory and hemodynamic parameters were assessed prior to extubation and 6 hours after extubation. The primary clinical outcomes measured were improvement in oxygenation, ventilation-free days, re-intubation, ICU length of stay, and mortality. RESULTS: The two groups demonstrated similar hemodynamic patterns before and after extubation. The respiratory rate was slightly elevated in both groups after extubation with no differences observed between groups. There were no statistically significant clinical differences in PaCO2. However, the use of HFNC resulted in improved PaO2/FiO2 post-extubation (P < 0.05). There were more ventilator-free days in the HFNC group (P< 0.05) and fewer patients required reintubation (1 vs. 6). There were no differences in ICU length of stay or mortality. CONCLUSION: This study demonstrated better oxygenation for patients treated with HFNC compared with NRB after extubation. HFNC may be more effective than standard oxygen supply devices for oxygenation in the post-extubation period.

Red blood cell transfusion in neurosurgical patients.

PURPOSE OF REVIEW: Anemia is common in neurosurgical patients, and is associated with secondary brain injury. Although recent studies in critically ill patients have shifted practice toward more restrictive red blood cell (RBC) transfusion strategies, the evidence for restrictive versus liberal transfusion strategies in neurosurgical patients has been controversial. In this article, we review recent studies that highlight issues in RBC transfusion in neurosurgical patients. RECENT FINDINGS: Recent observational, retrospective studies in patients with traumatic brain injury, subarachnoid hemorrhage, and intracranial hemorrhage have demonstrated that prolonged anemia and RBC transfusions were associated with worsened outcomes. Anemia in patients with ischemic stroke was associated with increased ICU length of stay and longer mechanical ventilation requirements, but mortality and functional outcomes did not improve with RBC transfusion. In elective craniotomy, perioperative anemia was associated with increased hospital length of stay but no difference in 30-day morbidity or mortality. SUMMARY: There is a lack of definitive evidence to guide RBC transfusion practices in neurosurgical patients. Large randomized control trials are needed to better assess when and how aggressively to transfuse RBCs in neurosurgical patients.

Postoperative ICU management of patients after subarachnoid hemorrhage.

PURPOSE OF REVIEW: This article reviews recent advances in the postoperative ICU management of patients after subarachnoid hemorrhage (SAH), especially with regards to hemodynamic management, methods of improving neurological outcomes, and management of cardiac and pulmonary complications. RECENT FINDINGS: Several hemodynamic monitors and parameters may be useful for guiding volume therapy, including cardiac output, stroke volume variation monitoring, and global end-diastolic volume index. Early goal-directed hemodynamic therapy after SAH has recently been shown to improve clinical outcomes in patients with a poor clinical grade or coexisting cardiopulmonary complications. Recent laboratory and imaging modalities are being developed to identify patients at risk for developing vasospasm after SAH. Evidence for the use of various prophylactic adjuvant therapies to prevent vasospasm, including magnesium, phosphodiesterase 3 inhibitors, and therapeutic hypothermia, is emerging. Intrathecal administration of vasodilators or fibrinolytics may have offered advantages over systemic drug administration in the treatment of vasospasm. Pulmonary and cardiac complications are common after SAH, and are associated with an increased risk of mortality. SUMMARY: The postoperative ICU period after SAH is associated with a significant morbidity and mortality risk, and recent studies have greatly contributed to our understanding of how to optimally manage these patients.

Preoperative Risk Assessment Before Elective Craniotomy: Are Aspirin, Arrhythmias, Deep Venous Thromboses, and Hyperglycemia Contraindications to Surgery?

OBJECTIVE: Perioperative risk assessment and stratification before craniotomy is necessary to identify and optimize modifiable risk factors. Due to the high costs of diagnostic testing and concerns for delaying surgery, some have questioned whether and when surgery delays are warranted and supported by the current body of literature. The objective of this scoping review was to evaluate the available evidence on the prognostic value of preoperative risk assessment before anesthesia for elective craniotomy. METHODS: In this scoping review, we reviewed 156 papers that assess preoperative risk assessment before elective craniotomy, of which 27 papers were included in the final analysis. RESULTS: There is little high-quality evidence to suggest significant risk reduction when 4 common preexisting abnormalities are present: preoperative chronic aspirin therapy, cardiac arrhythmias, deep vein thrombosis, or hyperglycemia. CONCLUSIONS: The risk of delaying craniotomy should ultimately be weighed against the perceived risks associated the patient's comorbid conditions and should be considered on an individualized basis.

Awake Robotic Minimally-Invasive Transforaminal Lumbar Interbody Fusion under Spinal Anesthesia: a Prospective Study with 1-year Follow-up.

BACKGROUND: We describe our protocol and outcomes of awake robotic minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) under spinal anesthesia. METHODS: We conducted a prospective study of 10 consecutive patients undergoing awake robotic single-level MIS-TLIF with the Mazor X robot. We prospectively collected patient-reported outcomes (back and leg pain VAS, and Oswestry Disability Index) pre-operatively, at the 1-month, and 1-year follow-up, and assessed fusion and screw placement accuracy with the 1-year CT scan. RESULTS: Median age was 61 years (IQR=57.7-66); median BMI 27kg/m2. No intraoperative complications reported. 9/10 patients were discharged home, 50% discharged on the day of surgery. Median length of stay was 16.5h (IQR=5-35.5); median follow-up 12.5 months (IQR=12-13.5), with 9 patients having at least 12-month follow-up, with CT scans documenting good screw placement (Gertzbein-Robbins Grade A) and solid bony fusion. Median pre-op back pain VAS was 7.8 (IQR=6.9-8) versus 1.5 (IQR=0-3.2) at 1-month post-op, p<0.01, and 0 (IQR=0-1) at 1-year follow-up, p<0.01; median preop leg pain 8 (IQR=7.4-8) versus 0 (IQR=0-1.2) at 1-month post-op, p<0.01, and 0 (IQR=0-2) at 1-year follow-up, p<0.01; median preop ODI 47.5 (IQR=27.8-57.5) versus 4 (IQR=0-16) at 1-month post-op, p<0.01, and 0 (IQR=0-7) at 1-year follow-up, p<0.01. Median preoperative disc high of the index level 8mm (IQR=2.4-9.5), versus 11.4mm (IQR=9.2-11.2) postoperatively, p< 0.01. Median preoperative lordosis of the index level 5 degrees (IQR=3.4-8.5), versus 10.1 degrees (7.3-12.2) postoperatively, p< 0.01. CONCLUSIONS: Our study showed significant improvement in PROs at 1-month and 1-year follow-up after awake robotic MIS-TLIF, as well as solid bony fusion on CT scans.