Characterizing the impact of thermoregulation in patients after cardiac arrest: a retrospective cohort study.

PURPOSE: Core body temperature has been extensively investigated as a thereuptic target in care after cardiac arrest. Nevertheless, the integrity of thermoregulation in patients after cardiac arrest has not been well studied. We sought to evaluate whether low spontaneous body temperature after cardiac arrest is associated with increased death and a worse neurologic outcome, and whether patients with low spontaneous body temperature exhibit features suggestive of impaired thermoregulation. METHODS: We conducted a single-centre retrospective cohort study. We included all adult patients who underwent temperature control with hypothermia after cardiac arrest between 1 January 2014 and 30 June 2020. The primary exposure was low spontaneous core body temperature (< 35 °C) at initiation of hypothermia therapy. The primary outcome was in-hospital death and the secondary outcome was poor neurologic outcomes at discharge. RESULTS: Five hundred and ninety-seven adult patients, comprising both in- and out-of-hospital cardiac arrests, were included. Patients with low spontaneous body temperature also had slightly lower average temperature, and more frequent transient but controlled breakthrough fever episodes in the first 24 hr. In the multivariable logistic regression analysis, low spontaneous body temperature was associated with higher odds of in-hospital death (odds ratio, 2.9; 95% confidence interval, 1.9 to 4.2; P < 0.001). CONCLUSION: In this single-centre retrospective cohort study, low spontaneous core body temperature was associated with poor outcomes in patients after cardiac arrest. Patients with low spontaneous body temperature also exhibited features suggestive of impaired thermoregulation. Further research is needed to determine whether body temperature upon presentation reflects the robustness of the patient's underlying physiology and severity of brain insult after a cardiac arrest.

RéSUMé: OBJECTIF: La température corporelle centrale a fait l'objet d'études approfondies en tant que cible thérapeutique dans les soins après un arrêt cardiaque. Néanmoins, l'intégrité de la thermorégulation après un arrêt cardiaque n'a pas été bien étudiée. Nous avons cherché à évaluer si une température corporelle spontanément basse après un arrêt cardiaque était associée à une augmentation de la mortalité et à une issue neurologique plus grave, et si les individus ayant une température corporelle spontanément basse présentaient des caractéristiques suggérant une altération de la thermorégulation. MéTHODE: Nous avons mené une étude de cohorte rétrospective monocentrique. Nous avons inclus tou·tes les patient·es adultes ayant bénéficié d'un contrôle de température lors d'une hypothermie après un arrêt cardiaque entre le 1er janvier 2014 et le 30 juin 2020. L'exposition principale était une température corporelle centrale spontanément basse (< 35 °C) au début du traitement de l'hypothermie. Le critère d'évaluation principal était le décès à l'hôpital, et le critère d'évaluation secondaire était de mauvaises issues neurologiques à la sortie de l'hôpital. RéSULTATS: Cinq cent quatre-vingt-dix-sept patient·es adultes, ayant subi des arrêts cardiaques à l'hôpital ou hors de l'hôpital, ont été inclus·es. Les patient·es ayant une température corporelle spontanément basse avaient également une température moyenne légèrement plus basse et des épisodes de fièvre paroxystique transitoires mais contrôlés plus fréquents au cours des premières 24 heures. Dans l'analyse de régression logistique multivariée, une température corporelle spontanément basse était associée à une probabilité plus élevée de décès à l'hôpital (rapport de cotes, 2,9; intervalle de confiance à 95 %, 1,9 à 4,2; P < 0,001). CONCLUSION: Dans cette étude de cohorte rétrospective monocentrique, une température corporelle centrale spontanément basse a été associée à de mauvais devenirs après un arrêt cardiaque. Les patient·es présentant une température corporelle spontanément basse présentaient également des caractéristiques suggérant une altération de la thermorégulation. D'autres recherches sont nécessaires pour déterminer si la température corporelle lors de la présentation reflète la robustesse de la physiologie sous-jacente des patient·es et la gravité de la lésion cérébrale après un arrêt cardiaque.

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.

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.

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).

Automated Nerve Monitoring in Shoulder Arthroplasty: A Prospective Randomized Controlled Study.

BACKGROUND: Evoked potential monitoring is believed to prevent neurologic injury in various surgical settings; however, its clinical effect has not been scrutinized. It was hypothesized that an automated nerve monitor can minimize intraoperative nerve injury and thereby improve clinical outcomes in patients undergoing shoulder arthroplasty. METHODS: A prospective, blinded, parallel group, superiority design, single-center, randomized controlled study was conducted. Study participants were equally randomized into either the automated nerve-monitored or the blinded monitored groups. The primary outcome was intraoperative nerve injury burden as assessed by the cumulative duration of nerve alerts. Secondary outcomes were neurologic deficits and functional scores of the operative arm, and the quality of life index (Euro Quality of life-5 domain-5 level score) at postoperative weeks 2, 6, and 12. RESULTS: From September 2018 to July 2019, 213 patients were screened, of whom 200 were randomized. There was no statistically significant difference in the duration of nerve alerts between the automated nerve-monitored and control groups (median [25th, 75th interquartile range]: 1 [0, 18] and 5 [0, 26.5]; Hodges-Lehman difference [95% CI]: 0 [0 to 1] min; P = 0.526). There were no statistically significant differences in secondary outcomes between groups. However, in the ancillary analysis, there were reductions in neurologic deficits and improvements in quality of life index occurring in both groups over the course of the study period. CONCLUSIONS: Protection from nerve injury is a shared responsibility between surgeons and anesthesiologists. Although a progressive improvement of clinical outcomes were observed over the course of the study in both groups as a consequence of the real-time feedback provided by the automated nerve monitor, this trial did not demonstrate that automated nerve monitoring by itself changes important clinical outcomes compared with no monitoring.

A novel approach of using brachial plexus blockade as an experimental model for diagnosis of intraoperative nerve dysfunction with somatosensory evoked potentials: a blinded proof-of-concept study.

PURPOSE: Intraoperative nerve dysfunction has been difficult to investigate because of its rarity and unpredictable occurrence. The diagnostic test attributes of nerve function monitors have not been clearly defined. This proof-of-concept study aimed to assess the feasibility of using brachial plexus blockade (BPB) in awake patients as an experimental model for nerve dysfunction to characterize the diagnostic test attributes of somatosensory evoked potentials (SSEPs). METHODS: We obtained baseline SSEPs and neurologic function in patients and subsequently placed BPBs (experimental model) to generate progressive states of nerve dysfunction. We monitored SSEP changes (index test) and neurologic symptoms (reference standard) simultaneously during the onset of BPB to determine the temporal relationships and diagnostic test attributes of SSEPs. RESULTS: Brachial plexus blockade produced differential motor and sensory dysfunction that allowed simultaneous clinical and neurophysiologic assessment. One hundred and fifty-seven pairs of multiple data points from 14 patients were included for final analysis. The onset of abnormal SSEP signals almost always preceded the onset of neurologic symptoms. The sensitivities and specificities of SSEP to detect the impairment of power (motor rating score ≤ 4/5), cold sensation, and two-point discrimination were 100% and 67%, 99% and 55%, and 100% and 46%, respectively. CONCLUSION: This study found that BPB can produce sufficient differential nerve dysfunction to allow adequate evaluation of the diagnostic test attributes of SSEPs as a nerve monitor. The results of this study may stimulate further work on refining intraoperative nerve dysfunction models and diagnostic nerve function monitors. TRIAL REGISTRATION: www.clinicaltrials.gov (NCT03409536); registered 24 January 2018.

RéSUMé: OBJECTIF: La dysfonction nerveuse peropératoire est difficile à étudier en raison de sa rareté et de son imprévisibilité. Les attributs d'un test diagnostique des moniteurs de la fonction nerveuse n'ont pas été clairement définis. Cette étude de démonstration de faisabilité visait à évaluer la faisabilité de l'utilisation d'un bloc du plexus brachial (BPB) chez des patients éveillés comme modèle expérimental de la dysfonction nerveuse afin de caractériser les attributs de test diagnostique des potentiels évoqués somesthésiques (PES). MéTHODE: Nous avons enregistré les PES et la fonction neurologique de base des patients, puis administré des BPB (modèle expérimental) pour générer des états progressifs de dysfonction nerveuse. Nous avons surveillé simultanément les changements des PES (test pour déterminer l'indicateur) et les symptômes neurologiques (norme de référence) pendant l'évolution du BPB afin de déterminer les relations temporelles et les attributs de test diagnostique des PES. RéSULTATS: Le bloc du plexus brachial a produit une dysfonction motrice et sensorielle différentielle qui nous a permis de procéder à une évaluation clinique et neurophysiologique simultanée. Cent cinquante-sept paires de points de données multiples issues de 14 patients ont été incluses pour l'analyse finale. L'apparition de signaux de PES anormaux a presque toujours précédé l'apparition de symptômes neurologiques. Les sensibilités et les spécificités des PES pour détecter la perte de force (score moteur ≤ 4/5), la sensation de froid et la discrimination à deux points étaient de 100 % et 67 %, 99 % et 55 %, et 100 % et 46 %, respectivement. CONCLUSION: Cette étude a constaté que le bloc du plexus brachial peut produire une dysfonction nerveuse différentielle suffisante pour permettre l'évaluation adéquate des attributs de test diagnostique des PES en tant que moniteur nerveux. Les résultats de cette étude pourraient motiver d'autres travaux sur l'amélioration des modèles de dysfonction nerveuse peropératoire et des moniteurs diagnostiques de la fonction nerveuse. ENREGISTREMENT DE L'éTUDE: www.clinicaltrials.gov (NCT03409536); enregistrée le 24 janvier 2018.

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.

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.

Perioperative Peripheral Nerve Injury After General Anesthesia: A Qualitative Systematic Review.

Perioperative peripheral nerve injury (PNI) is a well-recognized complication of general anesthesia that continues to result in patient disability and malpractice claims. However, the multifactorial etiology of PNI is often not appreciated in malpractice claims given that most PNI is alleged to be due to errors in patient positioning. New advances in monitoring may aid anesthesiologists in the early detection of PNI. This article reviews recent studies of perioperative PNI after general anesthesia and discusses the epidemiology and potential mechanisms of injury and preventive measures. We performed a systematic literature search, reviewed the available evidence, and identified areas for further investigation. We also reviewed perioperative PNI in the Anesthesia Closed Claims Project database for adverse events from 1990 to 2013. The incidence of perioperative PNI after general anesthesia varies considerably depending on the type of surgical procedure, the age and risk factors of the patient population, and whether the detection was made retrospectively or prospectively. Taken together, studies suggest that the incidence in a general population of surgical patients undergoing all types of procedures is <1%, with higher incidence in cardiac, neurosurgery, and some orthopedic procedures. PNI represent 12% of general anesthesia malpractice claims since 1990, with injuries to the brachial plexus and ulnar nerves representing two-thirds of PNI claims. The causes of perioperative PNI after general anesthesia are likely multifactorial, resulting in a "difficult to predict and prevent" phenomenon. Nearly half of the PNI closed claims did not have an obvious etiology, and most (91%) were associated with appropriate anesthetic care. Future studies should focus on the interaction between different mechanisms of insult, severity and duration of injury, and underlying neuronal reserves. Recent automated detection technology in neuromonitoring with somatosensory evoked potentials may increase the ability to identify at-risk patients and individualize patient management.

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.

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).

Cardiac Output and Cerebral Blood Flow: The Integrated Regulation of Brain Perfusion in Adult Humans.

Cerebral blood flow (CBF) is rigorously regulated by various powerful mechanisms to safeguard the match between cerebral metabolic demand and supply. The question of how a change in cardiac output (CO) affects CBF is fundamental, because CBF is dependent on constantly receiving a significant proportion of CO. The authors reviewed the studies that investigated the association between CO and CBF in healthy volunteers and patients with chronic heart failure. The overall evidence shows that an alteration in CO, either acutely or chronically, leads to a change in CBF that is independent of other CBF-regulating parameters including blood pressure and carbon dioxide. However, studies on the association between CO and CBF in patients with varying neurologic, medical, and surgical conditions were confounded by methodologic limitations. Given that CBF regulation is multifactorial but the various processes must exert their effects on the cerebral circulation simultaneously, the authors propose a conceptual framework that integrates the various CBF-regulating processes at the level of cerebral arteries/arterioles while still maintaining autoregulation. The clinical implications pertinent to the effect of CO on CBF are discussed. Outcome research relating to the management of CO and CBF in high-risk patients or during high-risk surgeries is needed.

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.

Comparison of propofol and volatile agents for maintenance of anesthesia during elective craniotomy procedures: systematic review and meta-analysis.

BACKGROUND: Both propofol and volatile anesthetics are commonly used for maintenance of anesthesia in patients undergoing neurosurgical procedures. The effects of these two classes of drugs on cerebral hemodynamics have been compared in many clinical trials The objectives of this review were to evaluate the cerebral hemodynamic effects, operative conditions, recovery profiles, postoperative complications, and neurological outcomes of propofol-based vs volatile-based anesthesia for craniotomy. METHODS: MEDLINE®, EMBASE™, Cochrane, and other relevant databases were searched for randomized controlled trials that compared propofol-maintained anesthesia with volatile-maintained anesthesia in adult patients undergoing elective craniotomy. The primary outcome measure was the intraoperative brain relaxation score. Secondary outcome measures included intraoperative cerebral hemodynamics (intracranial pressure [ICP], cerebral perfusion pressure [CPP]), cardiovascular changes, recovery profiles, postoperative complications, and clinical outcomes (neurological morbidity, mortality, quality of life). A meta-analysis was conducted using a random effects model to compare the outcomes of the two anesthetic techniques. RESULTS: Fourteen studies (1,819 patients) met inclusion criteria and were analyzed. Brain relaxation scores were similar between the two groups after dural opening; however, ICP was lower (weighted mean difference of -5.2 mmHg; 95% confidence interval -6.81 to -3.6) and CPP was higher (weighted mean difference of 16.3 mmHg; 95% confidence interval 12.2 to 20.46) in patients receiving propofol-maintained anesthesia. Postoperative complications and recovery profiles were similar between the two groups, except for postoperative nausea and vomiting being less frequent with propofol-maintained anesthesia. There were inadequate data to perform a meta-analysis on clinical outcome. CONCLUSION: Propofol-maintained and volatile-maintained anesthesia were associated with similar brain relaxation scores, although mean ICP values were lower and CPP values higher with propofol-maintained anesthesia. There are inadequate data to compare clinically significant outcomes such as neurological morbidity or mortality.

Real-time 3D Transesophageal Echocardiography for the Placement of Ventriculoatrial Shunt: A Case Series and Technical Note.

BACKGROUND: Ventriculoatrial (VA) shunts are used to manage hydrocephalus and idiopathic intracranial hypertension when peritoneal drainage of cerebrospinal fluid is not feasible. The technique of distal catheter placement during VA shunt insertion is controversial, especially between fluoroscopy-guided and transesophageal echocardiography (TEE)-guided techniques. METHODS: We retrospectively reviewed our utilization of 2-dimensional (2D) ultrasound-guided internal jugular vein catheterization combined with 3-dimensional (3D) TEE-guided distal VA shunt placement and compared it to the conventional fluoroscopy-guided technique. RESULTS: Ten patients underwent 18 VA shunt insertion procedures between November 2012 and October 2022. The patients had a mean (SD) age of 50 (19) years, body mass index of 35 (14) m/kg², and minimal comorbidities. All had previously undergone failed ventriculoperitoneal shunt procedures. The use of 2D ultrasound to guide internal jugular vein catheterization and 3D TEE to guide distal catheter placement resulted in 22-minute shorter surgical times compared with the fluoroscopy-guided technique (91 minutes vs. 113 minutes, respectively). No complications were noted with either technique. CONCLUSIONS: The combined use of 2D ultrasound and 3D TEE allowed for faster procedure times and more precise distal catheter confirmation, contributing to a more streamlined surgical procedure. This small case series underscores the feasibility, efficiency, and safety of anesthesiologist-delivered combined 2D ultrasound and 3D TEE during VA shunt insertion. The use of 3D TEE allows repeated confirmation of distal catheter position and has potential to improve patient safety during rare but complex VA shunt insertion procedures.

The Impact of Neuroanesthesia Fellowship Training and Anesthesiologist-Surgeon Dyad Volume on Patient Outcomes in Adult Spine Surgery: A Population-Based Study.

INTRODUCTION: Extensive research has explored the impact of surgeons' characteristics on patient outcomes; however, the influence of anesthesiologists remains understudied. We performed a population-based retrospective cohort study to investigate the impact of anesthesiologists' characteristics on in-hospital morbidity after spine surgery. METHODS: Adult patients who underwent spine surgery at the London Health Science Centre, Ontario, Canada between January 1, 2010 and June 30, 2023 were included in this study. Data was extracted from the local administrative database. Five anesthesiologists' characteristics (neuroanesthesia fellowship and residency training backgrounds, surgeon familiarity, annual case volume, and sex) were examined as primary exposures. The primary outcome was composite in-hospital morbidity, encompassing 141 complications. Multivariable logistic regression was performed to assess the association between anesthesiologists' characteristics and postoperative morbidity with adjustment of patients' sex, Charlson Comorbidities Index, surgical complexity, and surgeon characteristics. RESULTS: A total of 7692 spine surgeries were included in the analysis. Being a neuroanesthesia fellowship-trained anesthesiologist and high anesthesiologist-surgeon annual dyad volume were associated with reduction in in-hospital comorbidity; adjusted odds ratio (95% CI) of 0.58 (0.49-0.69; P<0.001) and 0.93 (0.91-0.95; P<0.001), respectively. Conversely, anesthesiologist annual case volume, characteristics of residency training and anesthesiologist sex showed only nuanced associations with outcomes. CONCLUSIONS: Neuroanesthesia fellowship training and high surgeon-anesthesiologist dyad familiarity was associated with a reduction in in-hospital morbidity following spine surgery. These findings underscore the superiority of structured fellowship education over case exposure experience alone, advocate for dedicated neuroanesthesia teams with high surgeon-anesthesiologist dyad volume and recognize neuroanesthesia as a crucial subspecialty in spine surgery.

Epidural Blood Patch for the Treatment of Spontaneous Intracranial Hypotension: A Case Series.

BACKGROUND: Epidural blood patch (EBP) is frequently used for the treatment of spontaneous intracranial hypotension (SIH) and anesthesiologists are often involved in performing such procedures. However, the optimal technique and approach of EBP remains uncertain. METHODS: This case series included adult patients with SIH who underwent EBPs at London Health Science Centre, Ontario, Canada between 2010 and 2022. Demographics, clinical presentations, investigations, and EBP treatment details were collected and analyzed. Univariate analysis was used to investigate the association of the variables with the likelihood of EBP 1-month efficacy and the efficacy duration of EBP. RESULTS: The study included 36 patients with SIH who received at least 1 EBP. EBPs provided immediate relief in almost all patients, albeit with diminishing effects over time. The 1-month efficacy improved with increasing number of EBP attempts (P=0.032, Fisher exact test), though no particular EBP technique or volume of injectate was associated with better efficacy (P=0.38, Fisher exact test). Though permanent resolution of symptoms was observed in only 24 of 82 EBPs (29%), 24 of 36 patients (67%) had permanent symptom resolution following repeated EBPs. CONCLUSIONS: EBP is a promising treatment and symptomatic relief option in patients suffering from the debilitating symptoms of SIH. Tailored EBP techniques, including use of targeted higher volume EBP and a multi-level catheter guided technique for refractory cases, showed efficacy in our institutional setting. Despite its limitations, this study contributes valuable insights and experiences into the use of EBP for treatment of SIH.