Assessing changes in regional cerebral hemodynamics in adults with a high-density full-head coverage time-resolved near-infrared spectroscopy device.

Significance: Cerebral oximeters have the potential to detect abnormal cerebral blood oxygenation to allow for early intervention. However, current commercial systems have two major limitations: (1) spatial coverage of only the frontal region, assuming that surgery-related hemodynamic effects are global and (2) susceptibility to extracerebral signal contamination inherent to continuous-wave near-infrared spectroscopy (NIRS). Aim: This work aimed to assess the feasibility of a high-density, time-resolved (tr) NIRS device (Kernel Flow) to monitor regional oxygenation changes across the cerebral cortex during surgery. Approach: The Flow system was assessed using two protocols. First, digital carotid compression was applied to healthy volunteers to cause a rapid oxygenation decrease across the ipsilateral hemisphere without affecting the contralateral side. Next, the system was used on patients undergoing shoulder surgery to provide continuous monitoring of cerebral oxygenation. In both protocols, the improved depth sensitivity of trNIRS was investigated by applying moment analysis. A dynamic wavelet filtering approach was also developed to remove observed temperature-induced signal drifts. Results: In the first protocol (28±5 years; five females, five males), hair significantly impacted regional sensitivity; however, the enhanced depth sensitivity of trNIRS was able to separate brain and scalp responses in the frontal region. Regional sensitivity was improved in the clinical study given the age-related reduction in hair density of the patients (65±15 years; 14 females, 13 males). In five patients who received phenylephrine to treat hypotension, different scalp and brain oxygenation responses were apparent, although no regional differences were observed. Conclusions: The Kernel Flow has promise as an intraoperative neuromonitoring device. Although regional sensitivity was affected by hair color and density, enhanced depth sensitivity of trNIRS was able to resolve differences in scalp and brain oxygenation responses in both protocols.

Preoperative assessment of postoperative delirium: a cross-sectional study of patients and anesthesiologists in Canada.

PURPOSE: We sought to evaluate 1) patient- and anesthesiologist-reported rates of postoperative delirium (POD) risk discussion during preoperative meetings, 2) patients' and anesthesiologists' ratings of the importance of POD, and 3) predictors of patient-reported discussion of POD risk during preoperative meetings. METHODS: In this multicentre two-part cross-sectional survey study, patients ≥ 65 yr scheduled to undergo elective noncardiac surgery completed a five-minute survey after preoperative anesthesia consultation. Patients were asked about their perception of POD importance, and whether they discussed or were assessed for POD risk. Anesthesiologists were surveyed using self-administered surveys circulated via institutional email lists. Anesthesiologists were asked about the frequency of POD risk assessment and discussion in older adults, tools used, and perception of POD-screening barriers. RESULTS: Four hundred and twelve (of 510 approached) patients (50% male; mean age, 73 yr) and 267 anesthesiologists (of 1,205 invited via e-mail) participated in this study conducted in five Canadian hospitals. Postoperative delirium screening and discussion was reported by 88/412 (22%) patients and 229/267 (86%) anesthesiologists. Postoperative delirium was rated as "somewhat-extremely" important by 64% of patients. A previous history of delirium, higher education, the number of daily medications, and longer surgical duration were associated with POD discussion. On average, anesthesiologists rated the importance of POD at 8/10, and 42% ranked "patient risk factors" as the top reason prompting discussion. CONCLUSION: The combined evaluation of patients' and anesthesiologists' perspectives provides valuable information on preoperative POD screening and risk assessment, and highlights areas for improvement in the current practice. Most factors we identified to be associated with higher odds of POD discussion are recognized risk factors of POD.

RéSUMé: OBJECTIF: Nous avons cherché à évaluer 1) les taux de discussion concernant le risque de delirium postopératoire (DPO) déclarés par les patient·es et les anesthésiologistes lors des rencontres préopératoires, 2) les évaluations des patient·es et des anesthésiologistes de l'importance de DPO, et 3) les prédicteurs d'une discussion telle que rapportée par les patient·es sur le risque de DPO pendant les rencontres préopératoires. MéTHODE: Dans ce sondage transversal multicentrique en deux parties, les patient·es ≥ 65 ans devant subir une chirurgie non cardiaque non urgente ont rempli un sondage de cinq minutes après la consultation d'anesthésie préopératoire. Les patient·es ont été interrogé·es sur leur perception de l'importance du DPO et si leur risque de DPO avait été discuté ou évalué. Des sondages auto-administrés ont été distribués aux anesthésiologistes via les listes de courriels institutionnelles. Ce sondage interrogeait les anesthésiologistes quant à la fréquence de l'évaluation et de la discussion des risques de DPO chez les personnes âgées, aux outils utilisés et à la perception des obstacles au dépistage de DPO. RéSULTATS: Quatre cent douze (des 510 personnes approchées) patient·es (50 % d'hommes; âge moyen, 73 ans) et 267 anesthésiologistes (sur 1205 invité·es par courriel) ont participé à cette étude menée dans cinq hôpitaux canadiens. Le dépistage et la discussion sur le delirium postopératoire ont été signalés par 88/412 (22 %) des patient·es et 229/267 (86 %) des anesthésiologistes. Le delirium postopératoire a été jugé « assez ­ extrêmement ¼ important par 64 % des patient·es. Des antécédents de delirium, des études supérieures, le nombre de médicaments quotidiens et une durée chirurgicale plus longue ont été associés à la discussion sur le DPO. En moyenne, les anesthésiologistes ont évalué l'importance du DPO à 8/10, et 42 % ont classé les « facteurs de risque liés au/à la patient·e ¼ comme la principale raison suscitant la discussion. CONCLUSION: L'évaluation combinée des points de vue des patient·es et des anesthésiologistes fournit des informations précieuses sur le dépistage préopératoire des DPO et l'évaluation des risques, et met en évidence les domaines à améliorer dans la pratique actuelle. La plupart des facteurs que nous avons identifiés comme étant associés à des probabilités plus élevées de discussion sur le DPO sont des facteurs de risque reconnus de DPO.

Point-of-care lung and cardiac ultrasound (LUCAS) study in hip fracture patients: a prospective cohort study.

PURPOSE: A clinical conflict often presented with hip fracture patients is whether to proceed with timely surgery or delay surgery until a formal echocardiogram is conducted. This study aimed to assess the impact of incorporating point-of-care lung and cardiac ultrasound (LUCAS) scans as part of the preoperative assessment for hip fracture patients. METHODS: We recruited 225 consecutive adult patients booked for urgent hip arthroplasty surgery. A LUCAS scan was performed for each patient. The anesthesiologists were asked to provide their anesthetic plans before and after acknowledging the results of the LUCAS scans. The primary endpoint was a composite outcome of changes to the anesthetic plan. The secondary outcomes included anesthesiologists' opinions of the LUCAS scans. RESULTS: One-hundred-ninety-eight patients were included. The majority of LUCAS findings were not severe. A common abnormal finding was hypovolemia (31%). One-hundred-and-six anesthetic management decisions were changed, with 59 of these changes being an escalation of the anesthetic plan, and 47 of these changes being a de-escalation. Eighty-three percent of anesthesiologists agreed that LUCAS affirmed their anesthetic plans and should be an integral part of the perioperative assessment. CONCLUSION: This study found that LUCAS scans did not significantly alter the anesthetic plan for hip fracture patients. Nevertheless, LUCAS scans can rule out severe cardiopulmonary conditions and allow for both escalation and de-escalation of care. In the setting of early hip surgery, LUCAS presents a viable option in selected patients to address the unmet need to allow for both timely surgery and comprehensive patient evaluation. STUDY REGISTRATION: ClinicalTrials.gov (NCT03275129); registered 8 July 2018.

RéSUMé: OBJECTIF: Une interrogation clinique qui existe souvent avec les patient·es se présentant avec une fracture de hanche est de savoir s'il faut procéder à une intervention chirurgicale rapidement ou retarder la chirurgie jusqu'à ce qu'un échocardiogramme formel soit réalisé. Cette étude visait à évaluer l'impact de l'intégration de l'échographie ciblée pulmonaire et cardiaque (LUCAS, Lung and Cardiac ultrasound) dans le cadre de l'évaluation préopératoire des personnes ayant subi une fracture de la hanche. MéTHODE: Nous avons recruté 225 patient·es adultes consécutif·ves devant bénéficier d'une arthroplastie urgente de la hanche. Une échographie de type LUCAS a été réalisée pour chaque patient·e. On a demandé aux anesthésiologistes de fournir leurs plans anesthésiques avant et après avoir pris connaissance des résultats des échographies de type LUCAS. Le critère d'évaluation principal était un résultat composite des modifications apportées au plan anesthésique. Les critères d'évaluation secondaires comprenaient les opinions des anesthésiologistes sur les échographies de type LUCAS. RéSULTATS: Cent quatre-vingt-dix-huit patient·es ont été inclus·es. La majorité des résultats de l'échographie de type LUCAS n'étaient pas graves. Un résultat anormal courant était l'hypovolémie (31 %). Cent six décisions de prise en charge anesthésique ont été modifiées, 59 de ces changements étant une escalade du plan anesthésique et 47 de ces changements étant une réduction. Quatre-vingt-trois pour cent des anesthésiologistes ont convenu que l'échographie de type LUCAS confirmait leurs plans anesthésiques et devrait faire partie intégrante de l'évaluation périopératoire. CONCLUSION: Cette étude a révélé que les échographies de type LUCAS ne modifiaient pas de manière significative le plan anesthésique pour les patient·es se présentant avec une fracture de hanche. Néanmoins, les échographies de type LUCAS peuvent exclure des affections cardiopulmonaires graves et permettre à la fois d'augmenter ou de réduire les soins périopératoires. Dans le cadre d'une chirurgie précoce de la hanche, l'échographie de type LUCAS présente une option viable chez une patientèle sélectionnée pour répondre à un besoin non satisfait afin de permettre à la fois une chirurgie rapide et une évaluation complète des patient·es. ENREGISTREMENT DE L'éTUDE: www.clinicaltrials.gov (NCT03275129); enregistrée le 8 juillet 2018.

Efficacy of perioperative pharmacological and regional pain interventions in adult spine surgery: a network meta-analysis and systematic review of randomised controlled trials.

BACKGROUND: Development of a widely accepted standardised analgesic pathway for adult spine surgery has been hampered by the lack of quantitative analysis. We conducted a systematic review and network meta-analysis (NMA) to compare, rank, and grade all pharmacological and regional interventions used in adult spine surgery. METHODS: A systematic search was performed in January 2021. We performed double study screening, selection, and data extraction. The co-primary outcomes were cumulative morphine consumption (mg) and visual analogue pain score (range 0-10) at postoperative 24 h. An NMA was performed using the Bayesian approach (random effects model). We also ranked and graded all analgesic interventions using the Grading of Recommendations Assessment, Development and Evaluation approach for NMA. RESULTS: We screened 5908 studies and included 86 randomised controlled studies, which comprised 6284 participants. Of 20 pharmacological and 10 regional interventions, the most effective intervention was triple-drug therapy, consisting of paracetamol, nonsteroidal anti-inflammatory drugs, and adjunct. The pooled mean reduction in morphine consumption and pain score at postoperative 24 h were -26 (95% credible interval [CrI]: -39 to -12) mg and -2.3 (95% CrI: -3.1 to -1.4), respectively. Double-drug therapy was less effective, but showed moderate morphine reduction in a range of -15 to -17 mg and pain score reduction in a range of -1 to -1.6. Single-agent interventions were largely ineffective. CONCLUSIONS: Triple-drug therapy is the most effective pain intervention in adult spine surgery with moderate-to-high certainty of evidence. We have also identified a graded analgesic effect, in which analgesic efficacy increased with the number of multimodal drugs used. SYSTEMATIC REVIEW REGISTRATION: PROSPERO (CRD42020171326).

Optical monitoring of cerebral perfusion and metabolism in adults during cardiac surgery with cardiopulmonary bypass.

During cardiac surgery with cardiopulmonary bypass (CPB), adequate maintenance of cerebral blood flow (CBF) is vital in preventing postoperative neurological injury - i.e. stroke, delirium, cognitive impairment. Reductions in CBF large enough to impact cerebral energy metabolism can lead to tissue damage and subsequent brain injury. Current methods for neuromonitoring during surgery are limited. This study presents the clinical translation of a hybrid optical neuromonitor for continuous intraoperative monitoring of cerebral perfusion and metabolism in ten patients undergoing non-emergent cardiac surgery with non-pulsatile CPB. The optical system combines broadband near-infrared spectroscopy (B-NIRS) to measure changes in the oxidation state of cytochrome c oxidase (oxCCO) - a direct marker of cellular energy metabolism - and diffuse correlation spectroscopy (DCS) to provide an index of cerebral blood flow (CBFi). As the heart was arrested and the CPB-pump started, increases in CBFi (88.5 ± 125.7%) and significant decreases in oxCCO (-0.5 ± 0.2 µM) were observed; no changes were noted during transitions off CPB. Fifteen hypoperfusion events, defined as large and sustained reductions in CPB-pump flow rate, were identified across all patients and resulted in significant decreases in perfusion and metabolism when mean arterial pressure dropped to 30 mmHg or below. The maximum reduction in cerebral blood flow preceded the corresponding metabolic reduction by 18.2 ± 15.0 s. Optical neuromonitoring provides a safe and non-invasive approach for assessing intraoperative perfusion and metabolism and has potential in guiding patient management to prevent adverse clinical outcomes.

Knowledge and perceptions about perioperative stroke: a cross-sectional survey of patients scheduled for non-neurologic and non-cardiac surgery.

PURPOSE: Perioperative stroke is associated with significant morbidity and mortality yet patients may not be aware of their risk or receive appropriate counselling. Our objectives were to 1) compare patient's perceived vs calculated risk of stroke; 2) determine level of worry; and 3) assess prior discussion about perioperative stroke risk amongst elective patients undergoing non-cardiac, non-neurologic surgery. METHODS: Over a consecutive four-week period, surveys were distributed at two pre-anesthetic clinics to adult patients scheduled for non-cardiac, non-neurologic surgery. The survey included questions about demographics, perioperative stroke risk factors, patient perception of their quantitative and qualitative stroke risk, level of worry about stroke, and risk discussions. We identified independent predictors of risk underestimation amongst medium- and high-risk patients. RESULTS: Six hundred patients completed the survey (response rate 78%). Of these, 479, 104, and 15 patients were classified as low-, medium-, and high-risk, respectively (with two patients missing this data point). Most medium- (86%) and high-risk (80%) patients did not identify their elevated risk. Amongst medium- and high-risk patients, independent predictors of risk underestimation were lower education and absence of kidney disease. Medium- and high-risk patients were more worried than low-risk patients about perioperative stroke (median [interquartile range] visual analogue scale score 2 [0.5-4] vs 1 [0-2], P = 0.001). Fewer than half of patients had discussed perioperative stroke previously (40%, 23%, and 12% of high-, medium-, and low-risk patients, respectively). CONCLUSIONS: Patients at higher risk of stroke frequently underestimate their risk of perioperative stroke. The majority of patients had not discussed perioperative stroke prior to anesthetic consultation.

Anesthetic management of complex spine surgery in adult patients: a review based on outcome evidence.

PURPOSE OF REVIEW: The aim of this article is to review the evidence regarding the anesthetic management of blood loss, pain control, and position-related complications of adult patients undergoing complex spine procedures. RECENT FINDINGS: The most recent evidence of the anesthetic management of complex spine surgery was identified with a systematic search and graded. In our review, prophylactic tranexamic acid and optimal prone positioning were shown to be effective blood conservation strategies with minimal risks to the patients. Cell saver was cost-effective in complex surgeries with expected blood loss of greater than 500 ml. As for pain control, most interventions only produced mild analgesic effects, suggesting a multimodal approach is necessary to achieve optimal pain control after spine surgery. Regional techniques and NSAIDs were effective but because of their risks, their usage should be discussed with the surgical team. Further studies are required to assess the effectiveness, cost-effectiveness, and risks associated with combined uses of different analgesic interventions. On the basis of the available evidence, we recommend a combined use of gabapentinoids, ketamine, and opioids to achieve optimal analgesia. Lastly, literature for position-related injuries is heavily relied on case reports and the Anesthesia Closed Claim Study because of their rarity. Therefore, we advocate for a structured team-based approach with checklists to minimize position-related complications. SUMMARY: As the number and complexity of spine procedures are being performed worldwide is increasing, we suggested to bundle the aforementioned effective interventions as part of an ERAS spine protocol to improve the patient outcome of spine surgery.

Intraoperative evoked potential monitoring for detecting cerebral injury during adult aneurysm clipping surgery: a systematic review and meta-analysis of diagnostic test accuracy.

OBJECTIVES: We aim to evaluate the diagnostic test accuracy (DTA) of intraoperative evoked potential (EP) monitoring to detect cerebral injury during clipping of cerebral aneurysms. DESIGN: Systematic review. DATA SOURCES: Major electronic databases including MEDLINE, EMBASE, LILACS. ELIGIBILITY CRITERIA: We included studies that reported the DTA of intraoperative EP monitoring during intracranial aneurysm clipping procedures in adult patients. DATA EXTRACTION AND SYNTHESIS: After quality assessment, we performed a meta-analysis using the bivariate random effects model, and calculated the possible range of DTA point estimates using a new best-case/worst-case scenario approach to quantify the impact of rescue intervention on DTA. RESULTS: A total of 35 studies involving 4011 patients were included. The quality of the primary studies was modest and the heterogeneity across studies was high. The pooled sensitivity and specificity for predicting postoperative neurological deficits for the somatosensory evoked potential (SSEP) monitoring was 59% (95% CI: 39% to 76%; I2: 76%) and 86% (95% CI: 77% to 92%; I2: 94%), for motor evoked potential (MEP) monitoring was 81% (95% CI: 58% to 93%; I2: 54%) and 90% (95% CI: 86% to 93%; I2: 81%), and for combined SSEP and MEP monitoring was 92% (95% CI: 62% to 100%) and 88% (95% CI: 83% to 93%). The best-case/worst-case range for the pooled point estimates for sensitivity and specificity for SSEP was 50%-63% and 81%-100%, and for MEP was 59%-74% and 93%-100%, and for combined SSEP and MEP was 89%-94% and 83%-100%. CONCLUSIONS: Due to the modest quality and high heterogeneity of the existing primary studies, it is not possible to confidently support or refute the diagnostic value of EP monitoring in cerebral aneurysm clipping surgery. However, combined SSEP and MEP appears to provide the best DTA for predicting postoperative stroke. Contrary to popular assertion, the modest sensitivity of SSEP monitoring is not explained by the use of rescue intervention. PROSPERO REGISTRATION NUMBER: CRD42015016884.

A Pilot Study of a Novel Automated Somatosensory Evoked Potential (SSEP) Monitoring Device for Detection and Prevention of Intraoperative Peripheral Nerve Injury in Total Shoulder Arthroplasty Surgery.

INTRODUCTION: Peripheral nerve injury is a potentially devastating complication after total shoulder arthroplasty (TSA) surgery. This pilot study aimed to assess the feasibility of using an automated somatosensory evoked potential (SSEP) device to provide a timely alert/intervention to minimize intraoperative nerve insults during TSA surgery. METHODS: A prospective, single-arm, observational study was conducted in a single university hospital. The attending anesthesiologist monitored the study participants using the EPAD automated SSEP device and an intervention was made if there was an alert during TSA surgery. The median, radial, and ulnar nerve SSEP on the operative arm, as well as the median nerve SSEP of the nonoperative arm were monitored for each patient. All patients were evaluated for postoperative neurological deficits 6 weeks postoperatively. RESULTS: In total, 21 patients were consented and were successfully monitored. In total, 4 (19%) patients developed intraoperative abnormal SSEP signal changes in the operative arm, in which 3 were reversible and 1 was irreversible till the end of surgery. Median and radial nerves were mostly involved (3/4 patients). The mean cumulative duration of nerve insult (abnormal SSEP) was 21.7±26.2 minutes. Univariate analysis did not identify predictor of intraoperative nerve insults. No patients demonstrated postoperative peripheral neuropathy at 6 weeks. CONCLUSIONS: A high incidence (19%) of intraoperative nerve insult was observed in this study demonstrating the feasibility of using an automated SSEP device to provide a timely alert and enable an intervention in order to minimize peripheral nerve injury during TSA. Further randomized studies are warranted.

The Trileaflet Mitral Valve.

With the advent of 3-dimensional echocardiography, visualization of the mitral valve has greatly improved. Recently, there has been an increase in reporting of a distinct entity called the "trileaflet mitral valve" using 3-dimensional echocardiography. It is controversial whether this is a new entity or an improved visualization of isolated mitral valve clefts or trifoliate left atrioventricular valve in the setting of an atrioventricular septal defect (AVSD) with intact septum. We present a case of a trifoliate valve, interpreting our findings based on a systematic review of previous publication on trileaflet mitral valves, isolated clefts in the mural (posterior) leaflet of the mitral valve, and trifoliate left atrioventricular valves with AVSD and intact septal structures. We describe the latter entity as a left atrioventricular valve because it never achieves the features of a normal mitral valve. We compare the features of isolated clefts of the mural leaflet of the mitral valve with trifoliate left atrioventricular valve found in the setting of AVSDs with intact septal structures to illustrate the current controversy regarding these conditions. In conclusion, our review suggested the reported trileaflet left atrioventricular valves is likely a misnomer because of a lack of consideration of embryologic development and nomenclature, rather than a greater appreciation and identification of a new distinct disease entity.

The Effects of Intraoperative Sedation on Surgical Outcomes of Deep Brain Stimulation Surgery.

BACKGROUND: Intraoperative sedation is often used to facilitate deep brain stimulation (DBS) surgery; however, these sedative agents also suppress microelectrode recordings (MER). To date, there have been no studies that have examined the effects of differing sedatives on surgical outcomes and the success of DBS surgery. METHODS: We performed a retrospective study to evaluate the effect of differing sedative agents on postoperative surgical outcomes at 6 months in parkinsonian adult patients who underwent DBS surgery, from January 2004 through December 2014, at one academic center. Surgical outcomes of DBS were evaluated using a simplified Unified Parkinson Diseases Rating Score-III and levodopa dose equivalent reduction at baseline and 6 months postoperatively. RESULTS: We analyzed data from 121 of 124 consecutive parkinsonian patients. Propofol, dexmedetomidine, remifentanil, and midazolam were used individually or in combination. All sedatives were routinely discontinued 20 to 30 minutes before MER, in accordance with our institutional protocol. We found no statistically significant association between the use of individual agent or combination of sedative agents and surgical outcomes at 6 months, the success of DBS, duration of MER, duration of stage 1 procedure, and perioperative complications. CONCLUSIONS: Our study showed that the choice of sedative agent was not associated with poor surgical outcomes after DBS surgery using MER and macrostimulation techniques in parkinsonian patients.

A Novel Automated Somatosensory Evoked Potential (SSEP) Monitoring Device for Detection of Intraoperative Peripheral Nerve Injury in Cardiac Surgery: A Clinical Feasibility Study.

OBJECTIVE: Peripheral nerve injury (PNI) is a common and potentially devastating complication in cardiac surgery. Somatosensory evoked potential (SSEP) monitoring is one of the modalities for PNI; however, its application is limited by complicated logistics. This study aimed to assess the feasibility of using a novel, automated SSEP device (EPAD; SafeOp Surgical, Hunt Valley, MD) for detection of intraoperative PNI during cardiac surgery. DESIGN: Prospective, observational study. SETTING: Single university hospital. PARTICIPANTS: Cardiac surgical patients. INTERVENTIONS: After Ethics Board approval and written consent, study participants were monitored using the EPAD automated SSEP device during cardiac surgery. All patients with prolonged and abnormal SSEP changes were evaluated postoperatively, and if they were symptomatic, they were referred for further nerve conduction and electromyographic assessment. MEASUREMENTS AND MAIN RESULTS: Of the 43 patients who consented to study inclusion, 33 were monitored successfully. With increasing clinical experience the authors encountered minimal technical issues, and satisfactory signals were obtained in most patients. Abnormal SSEP signal changes, which were encountered in 5 (15.2%) patients, were interpreted as impending PNI; 3 patients experienced prolonged signal changes (>1 h), and 2 (6.1%) of these developed symptomatic peripheral neuropathy that was confirmed with nerve conduction studies. CONCLUSIONS: The EPAD automated SSEP device is a viable option for detecting PNI during cardiac surgery. A high incidence of intraoperative peripheral nerve compromise and a 6.1% incidence of postoperative peripheral neuropathy were observed. This study reports the clinical feasibility of using the EPAD automated SSEP device; additional studies are required to evaluate the diagnostic test accuracy and the outcome benefit of routine SSEP monitoring in cardiac surgical patients.

Direct motor evoked potentials and cortical mapping using the NIM® nerve monitoring system: A technical note.

Motor evoked potentials (MEPs) are commonly used to prevent neurological injury when operating in close proximity to the motor cortex or corticospinal pathway. We report a novel application of the NIM® nerve monitoring system (Medtronic@ NIM response 3.0) for intraoperative direct cortical (dc)-MEPs monitoring. A 69-year-old female patient presented with a 4month history of progressive left hemiparesis resulting from a large right sided posterior frontal meningioma that abutted and compressed the motor cortex. Motor cortical mapping and MEPs were indicated. The patient was anesthetized and maintained on total intravenous anesthetics. Compound muscle action potentials (CMAP) of the right upper limb were monitored using the NIM system. After a craniotomy was performed, we first used the Ojemann stimulator (monopolar) for dc-stimulation and then switched to use the monopolar nerve stimulator probe of the NIM system. The CMAP response was successfully elicited using the NIM stimulating probe (pulse width=250s, train frequency=7pulses/s, current=20mA). A gross total resection of the tumor was achieved with intermittent cortical mapping of MEPs. There were no intraoperative complications and the patient's motor function was preserved after the surgery. In this case, we reported the successful use of the NIM nerve monitoring system to elicit dc-MEPs under general anesthesia. The advantages of using this system include a simple set up and application, neurosurgeon familiarity, wide availability and lower cost. dc-MEPs can be achieved using the NIM system. We conclude that the NIM nerve monitoring system is a feasible alternative to standard neurophysiological monitoring systems.

An update on the prone position: Continuing Professional Development.

PURPOSE: The purpose of this Continuing Professional Development module is to provide information needed to prepare for and clinically manage a patient in the prone position. PRINCIPAL FINDINGS: Prone positioning is required for surgical procedures that involve the posterior aspect of a patient. We searched MEDLINE(®) and EMBASE™ from January 2000 to January 2015 for literature related to the prone position and retrieved only original articles in English. We reviewed the advantages and disadvantages of various equipment used in prone positioning, the physiological changes associated with prone positioning, and the complications that can occur. We also reviewed strategies for the safe conduct and management of position-related complications. CONCLUSION: Increased age, elevated body mass index, the presence of comorbidities, and long duration of surgery appear to be the most important risk factors for complications associated with prone positioning. We recommend a structured team approach and careful selection of equipment tailored to the patient and surgery. The systematic use of checklists is recommended to guide operating room teams and to reduce prone position-related complications. Anesthesiologists should be prepared to manage major intraoperative emergencies (e.g., accidental extubation) and anticipate postoperative complications (e.g., airway edema and visual loss).

Anestesia para craneotomía en el paciente despierto: una actualización / Anesthesia for awake craniotomy: An update

Awake craniotomy has become a common procedure and its application has been continually evolving. Anesthesia for awake craniotomy poses a unique challenge to anesthesiologists. The aims of this article are to review under a critical perspective of the author, the current evidence and application of awake craniotomy and to briefly describe the principles of anesthetic management during this procedure.

La craneotomía en el paciente despierto se ha generalizado y su aplicación ha evolucionado continuamente. La anestesia para este procedimiento plantea un reto singular para los anestesiólogos. Son revisar, bajo una perspectiva crítica del autor, la evidencia actual y la aplicación de la craneotomía en el paciente despierto, y describir brevemente los principios del manejo anestésico durante el procedimiento.

Anesthetic management of patients undergoing intracranial bypass procedures.

Cerebral revascularization is used to augment or replace cerebral blood flow in patients at risk of developing cerebral ischemia. These include patients with moyamoya disease, occlusive cerebrovascular disease, skull base tumors, and complex aneurysms. Our aim in this review is to provide a comprehensive update of both surgical and anesthetic aspects of cerebral revascularization procedures. The anesthetic concerns for most patients presenting for different types of bypass procedures are similar and include the maintenance of adequate cerebral perfusion to prevent cerebral ischemia. Patients with complex aneurysms and tumors have additional considerations related to the surgical treatment of the underlying pathology.