Periprocedural management of patients presenting for neurointerventional procedures using flow diverters for complex intracranial aneurysms: An anesthetist's perspective - A narrative review.

Complex intracranial aneurysms pose significant challenges in the realm of neurointervention, necessitating meticulous planning and execution. This article highlights the crucial roles played by anesthetists in these procedures, including patient assessment, anesthesia planning, and continuous monitoring and maintaining hemodynamic stability, which are pivotal in optimizing patient safety. Understanding these complex procedures and their complications will aid the anesthetist in delivering optimal care and in foreseeing and managing the potential associated complications. The anesthetist's responsibility extends beyond the procedure itself to postprocedure care, ensuring a smooth transition to the recovery phase. Successful periprocedural anesthetic management in flow diverter interventions for complex intracranial aneurysms hinges on carefully orchestrating these elements. Moreover, effective communication and collaboration with the interventional neuroradiologist and the procedural team are emphasized, as they contribute significantly to procedural success. This article underscores the essential requirement for a multidisciplinary team approach when managing patients undergoing neurointerventions. In this collaborative framework, the expertise of the anesthetist harmoniously complements the skills and knowledge of other team members, contributing to the overall success and safety of these procedures. By providing a high level of care throughout the periprocedural period, anesthetists play a pivotal role in enhancing patient outcomes and minimizing the risks associated with these intricate procedures. In conclusion, the periprocedural anesthetic management of neurointervention using flow diverters for complex intracranial aneurysms is a multifaceted process that requires expertise, communication, and collaboration.

Evaluation and correlation of nociceptive response index and spectral entropy indices as monitors of nociception in anesthetized patients.

Objectives: During anesthesia, the response to these stimuli depends on the balance between nociception and antinociception. Recently, various monitoring systems based on the variables derived from electroencephalography, plethysmography, autonomic tone, reflex pathways, and composite algorithms have been introduced for monitoring nociception. The main aim of our study was to evaluate and correlate the physiological variables which reflect the autonomic nervous system response to nociception, such as heart rate (HR), systolic blood pressure (SBP), perfusion index (PI), and nociceptive response index (NRI), with the spectral entropy indices response entropy (RE) and RE-state entropy (SE), which reflects electromyographic (EMG) activation as a response to pain. Materials and Methods: This is a retrospective analysis of the data from a prospective study on the hypnotic and analgesic effects and the recovery profile of sevoflurane-based general anesthesia. Eighty-six patients undergoing single-agent sevoflurane anesthesia were recruited in the study. The study parameters, HR, SBP, SE, RE, RE-SE, PI, and NRI, were recorded at predefined time points before and after a standardized noxious stimulus. Correlation between the variables was carried out by applying the Pearson correlation equation for normal and the Spearman correlation equation for non-normally distributed data. Receiver operating characteristic (ROC) graphs were plotted, and the area under the curve was calculated to assess the diagnostic accuracy of post-stimulus NRI in detecting pain which was defined as RE-SE >10. Results: There was a significant increase in the SBP, HR, NRI, RE, SE, and RE-SE and a considerable decrease in PI values during the post-noxious period compared to the pre-noxious period. There was no correlation between the absolute values of NRI and entropy indices at T2. However, among the reaction values, there was a weak correlation between the reaction values of NRI and RE (r = 0.30; P = 0.05). The area under the ROC curve for NRI to detect pain as defined by RE-SE >10 was 0.56. Conclusion: During sevoflurane anesthesia, the application of noxious stimulus causes significant changes in variables reflecting sympathetic response and EMG activity. However, NRI failed to detect nociception, and there was only a weak correlation between the reaction values of NRI and RE-SE.

Anesthesia for same day neurosurgery with updates on awake craniotomy and awake spine surgery.

PURPOSE OF REVIEW: This article delves into recent advances in same-day neurosurgery (SDNS), specifically concerning indications, perioperative protocol, safety, and outcomes. Additionally, it explores the recent updates on awake craniotomy and awake spine surgery. RECENT FINDINGS: There is an evolving body of literature on studies about SDNS that reaffirm its safety and feasibility. awake craniotomy is associated with lesser neurological deficits and better survival benefits in patients with lesions in eloquent areas. Monitored anesthesia care, compared with the asleep-awake-asleep technique, is associated with lower failure rates, shorter procedure time, and shorter length of stay. However, the incidence of intraoperative seizures is lower with the asleep-awake-asleep technique. Propofol-based and dexmedetomidine-based anesthesia are similar with regard to procedure duration, intraoperative adverse events, and patient satisfaction; however, surgeon satisfaction is higher with dexmedetomidine-based anesthesia. In spine surgery, regional anesthesia when compared with general anesthesia, is associated with less intraoperative blood loss and a lower incidence of postoperative nausea and vomiting after 24 h. In addition, implementing an enhanced multimodal analgesia protocol improved disability scores and reduced the likelihood of postoperative complications. SUMMARY: SDNS offers promising prospects for patients and healthcare providers alike, with the potential to provide well tolerated, efficient, and cost-effective neurosurgical care in carefully selected cases.

A Perfusion Index-Based Evaluation and Comparison of Peripheral Perfusion in Sevoflurane and Isoflurane Anaesthesia: A Prospective Randomised Controlled Trial.

OBJECTIVE: Perfusion index has shown to be helpful in the operative and critical care settings to monitor peripheral tissue perfusion. Randomised controlled trials quantifying different agents' vasodilatory properties using perfusion index has been limited. Therefore, we undertook this study to compare the vasodilatory effects of isoflurane and sevoflurane using perfusion index. METHODS: This is a pre-specified sub-analysis of a prospective randomised controlled trial on the effects of inhalational agents at equipotent concentration. We randomly allocated patients scheduled for lumbar spine surgery to either isoflurane or sevoflurane groups. We recorded values of perfusion index at age-corrected 1 Minimum Alveolar Concentration (MAC) concentration at baseline, pre- and post-application of a noxious stimulus. The primary outcome of interest was the measure of vasomotor tone with perfusion index, and the secondary outcomes which were analysed were mean arterial pressure and heart rate. RESULTS: At age-corrected 1.0 MAC, there was no significant difference in the pre-stimulus haemodynamic variables and perfusion index between both groups. During the post-stimulus period, there was a significant increase in heart rate in the isoflurane group compared to the sevoflurane group, with no significant difference in the mean arterial pressure values between both groups. Though the perfusion index decreased during the post-stimulus period in both groups, there was no statistically significant difference between the 2 groups (P = .526, repeated-measures analysis of variance). CONCLUSION: In a steady state of age-corrected 1.0 MAC, isoflurane and sevoflurane had a similar perfusion index before and after a standardised nociceptive stimulus, which suggests that both of these agents have similar effect on peripheral perfusion and vasomotor tone.

Electrocardiographic changes in patients with raised intracranial pressure from supratentorial brain tumors.

Objectives: A wide variety of electrocardiographic (ECG) changes has been described in the context of neurological catastrophe. There has been diverse and plentiful literature emphasizing the cardiac changes in acute cerebrovascular events and traumatic brain injury. In stark contrast, there is scarce literature on the incidence of cardiac dysfunction caused by raised intracranial pressure (ICP) resulting from brain tumors. The study aimed to observe the ECG changes concurrent with intracranial hypertension resulting from supratentorial brain tumors. Materials and Methods: This is a pre-specified subgroup analysis of a prospective and observational study on cardiac function in patients presenting for neurosurgery. Data of 100 consecutive patients of either sex between 18 and 60 years who presented with primary supratentorial brain tumors were analyzed. The patients were divided into two groups: Group 1 consisted of patients without clinical and radiological features of raised ICP and Group 2 consisted of patients with clinical and radiological features of raised ICP. A 12-lead ECG was obtained for every patient on the day before the neurosurgical procedure as part of the pre-anesthetic assessment. The cardiologist and the neuroanesthetist independently examined the ECG, and it was then classified and coded as per the standardized Minnesota code. Statistical analysis was performed with IBM SPSS (release 22.0; IBM Corp., Armonk, NY, USA). The normality of the distribution of continuous variables was tested using the Shapiro-Wilk test. Normally distributed variables were expressed as Mean ± SD. All nominal or categorical variables are described as frequencies and percentages. Categorical variables were compared using the Chi-square test or the Fisher's exact test. The normally distributed continuous variables were compared using Student's t-test. "P < 0.05" was considered statistically significant. Results: About 6% in Group 1 and 32% in Group 2 had abnormal ECG. This was significantly different in Group 2 compared to Group 1 (P < 0.05). No patients in Group 1 had sinus bradycardia, whereas it was observed in 12% of the patients in Group 2 (P = 0.02). ST-segment depression was found in 12% of patients in Group 2, whereas none had it in Group 1 (P = 0.02). ST-segment elevation was noticed in 16 % in Group 2 and 2% in Group 1 (P = 0.01). T-wave abnormalities were found in 16% compared to 4% in Group 1 (P = 0.03). Conclusion: In patients with supratentorial tumors, we observed that those with raised ICP had a higher incidence of ECG changes than those with normal ICP. In addition, repolarization abnormalities and arrhythmias were significantly higher in patients with raised ICP.

A prospective-randomized placebo-controlled trial comparing the effects of nebulized dexmedetomidine v/s dexmedetomidine-lignocaine mixture on intraoperative hemodynamics and surgical field quality in patients undergoing endoscopic transnasal transsphenoidal pituitary tumor surgery.

Background: During transnasal transsphenoidal pituitary surgery (TNTSS), the primary objective is to maintain stable hemodynamics while ensuring ideal surgical conditions. This study aimed to investigate the effect of nebulized dexmedetomidine on hemodynamic parameters and the quality of the surgical field during TNTSS. Methods: Seventy-five patients scheduled for TNTSS were randomized into three groups of 25 each and received preoperative nebulization with 5 mL of nebulizing fluid consisting of 1.5 µg/kg of dexmedetomidine with saline in dexmedetomidine (D) group; 1.5 µg/kg of dexmedetomidine with 2% lignocaine in dexmedetomidine-lignocaine (DL) group and normal saline in the control (S) group. Heart rate (HR), mean blood pressure, Formmers score, anesthetic requirement, and emergence were evaluated for each group. Results: Group S had significantly higher HR and mean arterial pressure than the other two groups across various time points during surgery (P < 0.01). The total requirements for fentanyl, propofol, sevoflurane, and labetalol and the incidence of delayed emergence were significantly higher in the S group compared to the other two groups (P < 0.01). The D and DL groups exhibited significantly better surgical field conditions than the S group. In all the parameters assessed, patients in the D group outperformed those in the DL group. Conclusion: The administration of nebulized dexmedetomidine, both alone and in combination with lignocaine, resulted in stable hemodynamics, favorable operative conditions, reduced anesthetic requirement, and facilitated prompt emergence during TNTSS. Nebulized dexmedetomidine proved superior to its combination with lignocaine across all evaluated parameters.

Evaluation of markers of cerebral oxygenation and metabolism in patients undergoing clipping of cerebral aneurysm under total intravenous anesthesia versus inhalational anesthesia: A prospective randomized trial (COM-IVIN trial).

INTRODUCTION: Anesthetic goals in patients undergoing clipping of cerebral aneurysm include maintenance of cerebral blood flow, oxygenation, and metabolism to avoid cerebral ischemia and maintenance of hemodynamic stability. We intend to study the influence of anesthetic agents on the outcome of aneurysmal subarachnoid hemorrhage (SAH). MATERIALS AND METHODS: This is a prospective, randomized, parallel, single-center pilot trial approved by the Institutional Ethics Committee and is prospectively registered with the Clinical Trial Registry of India. Patients with aneurysmal SAH (aSAH) admitted to our institution for surgical clipping, fulfilling the trial inclusion criteria, will be randomized in a 1:1 allocation ratio utilizing a computerized random allocation sequence to receive either total intravenous anesthesia (n = 25) or inhalational anesthesia (n = 25). Our primary objective is to study the effects of these anesthetic techniques on cerebral oxygenation and metabolism in patients with aSAH. Our secondary objective is to evaluate the impact of these anesthetic techniques on the incidence of delayed cerebral ischemia and long-term patient outcomes in patients with aSAH. The Modified Rankin Score and Glasgow Outcome Scale (GOS) at discharge and 3 months following hospital discharge will be evaluated. An observer blinded to the study intervention will assess the outcome measures. DISCUSSION: This study will provide more insight as to which is the ideal anesthetic agent that offers a better neurophysiological profile regarding intraoperative cerebral oxygenation and metabolism, thereby contributing to better postoperative outcomes in aSAH patients.

At the Eye of the Hurricane! Perioperative Management of an Unoptimized Metastatic Pheochromocytoma Presenting for Emergency Neurosurgery.

Metastatic pheochromocytoma (PCC) is a rare entity arising from extra-adrenal tissue. We report the perioperative management of a young woman presenting with metastatic PCC to the vertebral body resulting in vertebral collapse and spinal cord compression necessitating emergency surgery. There are no reports of anesthetic management of a patient with unoptimized metastatic PCC presenting for emergency neurosurgery under general anesthesia. Our anesthetic goals were to maintain a deep anesthetic plane with stable hemodynamics, facilitate intraoperative neuromonitoring, manage catecholamine surges during anesthetic induction, tumor resection, and manage perioperative massive blood loss. The successful perioperative management of metastatic PCC has become possible with the vast armamentarium of anesthetic drugs and intraoperative advanced monitoring techniques. In addition, our role in understanding the pathophysiology and course of the disease is essential to ensure low morbidity and mortality of such cases in their most vulnerable perioperative period.

An Entropy-Based Prospective Randomized Controlled Trial to Evaluate the Analgesic and Hypnotic Effects of Equipotent Doses of Sevoflurane and Isoflurane in Patients Presenting for Spine Surgeries.

Objectives Minimal alveolar concentration (MAC) of anesthetic agents has been considered a suitable measure of the potency of inhalational anesthetics. Furthermore, it is assumed that equi-MAC concentrations of different anesthetic agents have a similar potency in suppressing responses to painful stimuli. Isoflurane and sevoflurane are two commonly used volatile anesthetic agents in spine surgeries. Therefore, these agents' hypnotic and analgesic potencies should be distinguished and comprehended for the optimal administration of anesthesia. Consequently, we undertook this study to compare the analgesic and hypnotic potencies between these agents at equi-MAC concentrations, using the entropy monitor. Materials and Methods Forty patients undergoing lumbar spine surgery were randomly assigned to two groups receiving either isoflurane ( n = 20) or sevoflurane ( n = 20). After induction, maintenance of anesthesia was done with age-corrected 1.0 MAC of either isoflurane or sevoflurane. A standardized noxious stimulus was provided to all the patients after achieving a steady state of 1.0 MAC. The state entropy (SE), response entropy (RE), and RE-SE were recorded at baseline, prestimulus, and poststimulus time points in both groups. Statistical Analyses Data are presented as frequency and percentages for categorical variables and mean ± standard deviation for continuous variables. The comparison of categorical variables between the two groups was made using the Fisher's exact test, and the Student's t -test was used for continuous variables. A p -value of < 0.05 was considered to be statistically significant. Results At age-corrected 1.0 MAC, there was no significant difference in the SE, RE, and RE-SE in both the groups at any time point. Conclusion Our study shows that during a steady state of age-corrected 1.0 MAC single-agent anesthesia, sevoflurane and isoflurane have comparable analgesic and hypnotic potencies as measured by entropy indices when a standardized nociceptive stimulus is provided.

Anesthetic Management of a Patient With Arterial Tortuosity Syndrome Undergoing Cerebral Revascularization Surgery-A Case Report.

Arterial tortuosity syndrome is a rare hereditary autosomal recessive connective tissue disorder characterized by elongation and tortuosity of the large- and medium-sized arteries. We present the case of a 13-year old child with arterial tortuosity syndrome who underwent occipital encephaloduroarteriomyosynangiosis for posterior circulation insufficiency. The constellation of clinical features in our patient portended significant anesthetic concerns, including difficult airway due to craniofacial abnormalities, risk of stroke, and myocardial infarction due to intracerebral and coronary arterial tortuosity and stenosis. The pertinent anesthetic implications are summarized, and we describe the anesthetic technique and use of multimodal neuromonitoring relevant for the case.

A Comparative Study to Evaluate the Efficacy of Virtual Versus Direct Airway Assessment in the Preoperative Period in Patients Presenting for Neurosurgery: A Quest for Safer Preoperative Practice in Neuroanesthesia in the Backdrop of the COVID-19 Pandemic!

Objectives Neurosurgical patients with cervical spine pathologies, craniofacial and craniovertebral junction anomalies, recurrent cervical spine, and posterior fossa surgeries frequently present with an airway that is anticipated to be difficult. Although the routine physical evaluation is nonaerosol-generating, Mallampati scoring, mouth opening, and assessment of lower cranial nerve function could potentially generate aerosols, imposing a greater risk of acquiring severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) infection. Moreover, airway evaluation requires the patient to remove the mask, thereby posing a greater risk to the assessing anesthesiologist. Thus, we designed this study to evaluate the efficacy of virtual airway assessment (VAA) done via telemedicine in comparison to direct airway assessment (DAA), and assess the feasibility of VAA as a part of the preanesthetic evaluation (PAE) of patients presenting for neurosurgery in the backdrop of the COVID-19 pandemic. Materials and Methods A total of 55 patients presenting for elective neurosurgical procedures were recruited in this prospective, observational study. The preoperative assessment of the airway was first done by a remote anesthetist via an encrypted video call, using a smartphone which served the purpose of telemedicine equipment, followed by a direct assessment by the attending anesthetist. The following parameters were assessed: mouth opening (MO), presence of any anomalies of tongue and palate, Mallampati classification (MPC) grading, thyromental distance (TMD), upper lip bite test (ULBT), neck movements, and Look-Evaluate-Mallampati-Obstruction-Neck mobility (LEMON) scoring system. Statistical Analysis Demographic parameters were expressed as mean ± SD. Agreement between the values obtained by VAA and DAA parameters were analyzed with the Kappa test. Results We observed a "perfect agreement" between the DAA and VAA with regard to MO. Assessment of ULBT, neck movements, and the LEMON score had an overall "almost perfect agreement" between the DAA and VAA. We also observed a "substantial agreement" between VAA and DAA during the assessment of MPC grading and TMD. Conclusion Our study shows that PAE and VAA via telemedicine can reliably be used as an alternative to direct physical preanesthetic consultation in the COVID-19 scenario. This could reduce unnecessary exposure of anesthesiologists to potential asymptomatic COVID-positive patients, thereby protecting the available skilled workforce, without any significant compromise to patient care.

Multimodal monitoring to aid detection and management of intraoperative seizures: a case report.

One of the primary goals in Neuroanesthesia is to preserve cerebral oxygenation and protect the brain from secondary injuries. Seizures have severe implications in the intraoperative period, as it can instigate an increase in cerebral metabolism and oxygen demand, thus causing cerebral hypoxia. Detection of intraoperative seizures is imperative in neurosurgical cases as the ramifications of intracranial hypertension and cerebral hypoxia caused by it can affect patient prognosis and perioperative outcomes. We report a case of detecting intraoperative seizures with the aid of patient state index and near infrared spectroscopy. Multi-modality monitoring aided in the management of a time-sensitive complication, which could otherwise have possibly led to secondary brain insult.

Perioperative Analgesia in Neurosurgery (PAIN): A national survey of pain assessment and management among neuroanesthesiologists of India.

BACKGROUND: Perioperative pain assessment and management in neurosurgical patients varies widely across the globe. There is lack of data from developing world regarding practices of pain assessment and management in neurosurgical population. This survey aimed to capture practices and perceptions regarding perioperative pain assessment and management in neurosurgical patients among anesthesiologists who are members of the Indian Society of Neuroanaesthesiology and Critical Care (ISNACC) and evaluated if hospital and pain characteristics predicted the use of structured pain assessment protocol and use of opioids for postoperative pain management. METHODS: A 26-item English language questionnaire was administered to members of ISNACC using Kwiksurveys platform after ethics committee approval. Our outcome measures were adoption of structured protocol for pain assessment and opioid usage for postoperative pain management. RESULTS: The response rate for our survey was 55.15% (289/524). One hundred eighteen (41%) responders informed that their hospital setup had a structured pain protocol while 43 (15%) responders reported using opioids for postoperative pain management. Predictors of the use of structured pain protocol were private setup (odds ratio [OR] 2.64; 95% confidence interval [CI] 1.52-4.59; P = .001), higher pain intensity (OR 0.37; 95% CI 0.21-0.64; P < .001) and use of pain scale (OR 7.94; 95% CI 3.99-15.81; P < .001) while availability of structured pain protocol (OR 2.04; 95% CI 1.02-4.05; P = .043) was the only significant variable for postoperative opioid use. CONCLUSIONS: Less than half of the Indian neuroanesthesiologists who are members of ISNACC use structured protocol for pain assessment and very few use opioids for postoperative pain management in neurosurgical patients.

Emergency neurological procedures during COVID-19 pandemic: Practical issues.

The novel coronavirus disease 2019 (COVID-19) has emerged as a global pandemic. A significant number of these patients would present to hospitals with neurological manifestations and neurosurgical emergencies requiring urgent treatment. The anesthesiologists should be prepared to manage these cases in an efficient and timely manner in the operating room, intensive care units, and interventional neuroradiology suites. The clinical course of the disease is in an evolving stage. As we acquire more knowledge about COVID-19, new recommendations and guidelines are being formulated and regularly updated. This article discusses the anesthetic management of urgent neurosurgical and neurointerventional procedures. In addition, a brief overview of intrahospital transport of neurologically injured patients has been addressed.

Role of Multimodal Cerebral Oximetry Monitoring in the Anesthetic Management of a Patient With High-Grade Intracranial Arteriovenous Malformation: A Case Report.

Near-infrared spectroscopy (NIRS) is a noninvasive monitor of regional brain tissue oxygenation, and jugular venous oximetry (SjvO2) is a monitor of global cerebral oxygenation. We report the role of intraoperative multimodal monitoring of cerebral oxygenation in the anesthetic management of a patient with grade III intracranial arteriovenous malformation (AVM) presenting for surgical excision. Real-time monitoring of cerebral oxygenation is of much relevance in high-grade AVMs where anesthetic management is focused on neuroprotection and prevention of cerebral hypoxia. Besides, it also helps in prediction, early detection, and judicious management of perioperative complications, which are commonly encountered in high-grade AVMs.

Effect of Low-Dose Dexmedetomidine on the Anesthetic and Recovery Profile of Sevoflurane-Based Anesthesia in Patients Presenting for Supratentorial Neurosurgeries: A Randomized Double-Blind Placebo-Controlled Trial.

Background Dexmedetomidine could be a suitable adjuvant in neuroanesthesia due to its analgesic and anesthetic-sparing properties with the added advantage of facilitating intraoperative neuromonitoring. However, its recovery profile is still debated upon, as in neuroanesthesia, a prompt recovery is essential for postoperative neurologic assessment. We designed this study to evaluate the effect of dexmedetomidine on the anesthetic and recovery profile of patients presenting for supratentorial neurosurgeries. Materials and Methods Forty adult patients undergoing supratentorial surgeries were recruited in this prospective, randomized, double-blinded study and were divided into two groups: group S and group SD. Both groups received sevoflurane and fentanyl for maintenance, whereas group SD alone received a low dose of dexmedetomidine infusion. Recovery parameters, opioid consumption, Richmond Agitation-Sedation Scale (RASS) and visual analogue scale (VAS) scores, incidence of nausea and vomiting, and intraoperative hemodynamics were analyzed. Results There were no statistically significant differences between the groups S and SD in case of recovery parameters-time taken (in minutes, presented as median with interquartile range [IQR]) for (1) eye-opening to command: 9.5 (8-18) versus 22.5 (5-47.5) ( p = 0.414); 2) following verbal command: 10.5 (8.25-29.5) versus 25 (10-28.75) ( p = 0.512); (3) extubation: 11 (9.25-22) versus 25 (10-30) ( p = 0.277); and (4) getting oriented to place, time, and date: 23 (20-52.75) versus 27.5 (25-36.5) ( p = 0.121). Fentanyl consumption was significantly less in group SD (451 ± 39.3) versus group S (524.3 ± 144.1) ( p = 0.034). The median RASS score with IQR and the median VAS scores with IQR were comparable between the groups at all time points. Of the 20 patients in group S, 5 had complaints of nausea and vomiting compared with none in the group SD, although it was not statistically significant. The hemodynamic parameters did not show a significant difference between the groups except for a surge in mean arterial pressure at 30 minutes in group S. Conclusion Low-dose dexmedetomidine as an adjuvant to sevoflurane- and fentanyl-based anesthesia could provide stable hemodynamics and lesser anesthetics and opioid consumption, without adversely affecting the recovery profile in patients undergoing supratentorial neurosurgical procedures.