Neuromonitoring in Carotid Surgery: Are the Results Obtained in Awake Patients Transferable to Patients Under Sevoflurane/Fentanyl Anesthesia?

Comparison of Methods for Monitoring Intra-operative Cerebral Perfusion in Patients Undergoing Carotid Endarterectomy with Selective Shunting: A Systematic Review and Network Meta-Analysis of Randomised Controlled Trials and Cohort Studies

OBJECTIVE

This study aimed to analyse the influence of different methods of monitoring cerebral perfusion (MCP) on stroke, death, and use of intraluminal shunt during carotid endarterectomy (CEA).

METHODS

A systematic review and network meta-analysis was conducted and registered in the PROSPERO registry (CRD42021246360). Medline, Embase, CENTRAL, and Web of Science were searched. Randomised controlled trials (RCTs) and cohort studies with > 50 participants that compared clinical outcomes for different MCP in patients undergoing CEA were included. Papers reporting one or a combination of two of the following MCPs were included in the analysis: awake testing (AT), near infrared spectroscopy (NIRS), electroencephalography (EEG), somatosensory evoked potential (SSEP), motor evoked potential (MEP), transcranial Doppler (TCD), and stump pressure (SP). A random effects network meta-analysis was performed using a binomial likelihood function with a specified logit link for peri-operative stroke or death and shunting as outcomes. Near infrared spectroscopy was excluded due to the lack of studies that could be used for statistical analysis.

RESULTS

Of 1 834 publications, 17 studies (15 cohort studies and two RCTs) including 21 538 participants were incorporated in the quantitative analysis. Electroencephalography was used in the largest number of participants (7 429 participants, six studies), while AT was used in the highest number of studies (10 studies). All monitoring modalities had worse outcomes with respect to stroke or death when compared with AT, with ORs ranging between 1.3 (95% credible interval [CrI] 0.2 - 10.9) for SSEP + MEP and 3.1 (CrI 0.3 - 35.0) for patients monitored with a combination of EEG and TCD. However, the wide CrI indicated that there is no statistically significant difference between the monitoring methods. Patients monitored with a combination of EEG and TCD had the lowest odds of being shunted, while SP had the highest odds of being shunted, also with no statistically significant difference.

CONCLUSION

There is a lack of high quality data on this topic in the literature. The present study showed no significant difference between monitoring methods investigated in the network meta-analysis.

A systematic review & meta-analysis on perioperative cerebral and hemodynamic monitoring methods during carotid endarterectomy

OBJECTIVE

To compare outcomes between different strategies of perioperative cerebral and hemodynamic monitoring during carotid endarterectomy.

DATA SOURCES

MEDLINE, EMBASE, CINAHL, and Cochrane CENTRAL databases were searched.

METHODS

This review was performed according to the PRISMA guidelines and prospectively registered in the international prospective register of systematic reviews (CRD42021241891). The GRADE approach was used to describe the methodological quality of the studies and certainty of the evidence. The primary outcome was 30-day stroke rate. Secondary outcomes measures are 30-day ipsilateral stroke, 30-day mortality, shunt rate and complication rates.

RESULTS

The search identified 3 460 articles. Seventeen RCTs, three prospective observational studies and seven registries were included, reporting on 236 983 patients. The overall pooled 30-day stroke rate is 1.8% (95% CI 1.4 - 2.2%), ranging from 0 - 12.6%. In RCT's the pooled 30-day stroke rate is 2.7% (95% CI 1.6 - 3.7%) compared to 1.3% (95%CI 0.8 - 1.8%) in the registries. The overall stroke risk decreased from 3.7% before the year 2000 to 1.6% after 2000. No significant differences could be identified between different monitoring and shunting strategies, although a trend to higher stroke rates in routine no shunting arms of RCTs was observed. Overall 30-day mortality, myocardial infarction and nerve injury rates are 0.6% (95%CI 0.4 - 0.8), 0.8% (95%CI 0.6-1.0) and 1.3% (95%CI 0.4-2.2), respectively.

CONCLUSIONS

No significant differences between the compared shunting and monitoring strategies are found. However, routine no shunting is not recommended. The available data is too limited to prefer one method of neuromonitoring over another method when selective shunting is applied.

Type of anaesthesia for acute ischaemic stroke endovascular treatment

BACKGROUND

The use of mechanical thrombectomy to restore intracranial blood flow after proximal large artery occlusion by a thrombus has increased over time and led to better outcomes than intravenous thrombolytic therapy alone. Currently, the type of anaesthetic technique during mechanical thrombectomy is under debate as having a relevant impact on neurological outcomes.

OBJECTIVES

To assess the effects of different types of anaesthesia for endovascular interventions in people with acute ischaemic stroke.

SEARCH METHODS

We searched the Cochrane Stroke Group Specialised Register of Trials on 5 July 2022, and CENTRAL, MEDLINE, and seven other databases on 21 March 2022. We performed searches of reference lists of included trials, grey literature sources, and other systematic reviews.  SELECTION CRITERIA: We included all randomised controlled trials with a parallel design that compared general anaesthesia versus local anaesthesia, conscious sedation anaesthesia, or monitored care anaesthesia for mechanical thrombectomy in acute ischaemic stroke. We also included studies reported as full-text, those published as abstract only, and unpublished data. We excluded quasi-randomised trials, studies without a comparator group, and studies with a retrospective design.

DATA COLLECTION AND ANALYSIS

Two review authors independently applied the inclusion criteria, extracted data, and assessed the risk of bias and the certainty of the evidence using the GRADE approach. The outcomes were assessed at different time periods, ranging from the onset of the stroke symptoms to 90 days after the start of the intervention. The main outcomes were functional outcome, neurological impairment, stroke-related mortality, all intracranial haemorrhage, target artery revascularisation status, time to revascularisation, adverse events, and quality of life. All included studies reported data for early (up to 30 days) and long-term (above 30 days) time points.

MAIN RESULTS

We included seven trials with 982 participants, which investigated the type of anaesthesia for endovascular treatment in large vessel occlusion in the intracranial circulation. The outcomes were assessed at different time periods, ranging from the onset of stroke symptoms to 90 days after the procedure. Therefore, all included studies reported data for early (up to 30 days) and long-term (above 30 up to 90 days) time points. General anaesthesia versus non-general anaesthesia(early) We are uncertain about the effect of general anaesthesia on functional outcomes compared to non-general anaesthesia (mean difference (MD) 0, 95% confidence interval (CI) -0.31 to 0.31; P = 1.0; 1 study, 90 participants; very low-certainty evidence) and in time to revascularisation from groin puncture until the arterial reperfusion (MD 2.91 minutes, 95% CI -5.11 to 10.92; P = 0.48; I² = 48%; 5 studies, 498 participants; very low-certainty evidence). General anaesthesia may lead to no difference in neurological impairment up to 48 hours after the procedure (MD -0.29, 95% CI -1.18 to 0.59; P = 0.52; I² = 0%; 7 studies, 982 participants; low-certainty evidence), and in stroke-related mortality (risk ratio (RR) 0.98, 95% CI 0.52 to 1.84; P = 0.94; I² = 0%; 3 studies, 330 participants; low-certainty evidence), all intracranial haemorrhages (RR 0.92, 95% CI 0.65 to 1.29; P = 0.63; I² = 0%; 5 studies, 693 participants; low-certainty evidence) compared to non-general anaesthesia. General anaesthesia may improve adverse events (haemodynamic instability) compared to non-general anaesthesia (RR 0.21, 95% CI 0.05 to 0.79; P = 0.02; I² = 71%; 2 studies, 229 participants; low-certainty evidence). General anaesthesia improves target artery revascularisation compared to non-general anaesthesia (RR 1.10, 95% CI 1.02 to 1.18; P = 0.02; I² = 29%; 7 studies, 982 participants; moderate-certainty evidence). There were no available data for quality of life. General anaesthesia versus non-general anaesthesia (long-term) There is no difference in general anaesthesia compared to non-general anaesthesia for dichotomous and continuous functional outcomes (dichotomous: RR 1.21, 95% CI 0.93 to 1.58; P = 0.16; I² = 29%; 4 studies, 625 participants; low-certainty evidence; continuous: MD -0.14, 95% CI -0.34 to 0.06; P = 0.17; I² = 0%; 7 studies, 978 participants; low-certainty evidence). General anaesthesia showed no changes in stroke-related mortality compared to non-general anaesthesia (RR 0.88, 95% CI 0.64 to 1.22; P = 0.44; I² = 12%; 6 studies, 843 participants; low-certainty evidence). There were no available data for neurological impairment, all intracranial haemorrhages, target artery revascularisation status, time to revascularisation from groin puncture until the arterial reperfusion, adverse events (haemodynamic instability), or quality of life. Ongoing studies We identified eight ongoing studies. Five studies compared general anaesthesia versus conscious sedation anaesthesia, one study compared general anaesthesia versus conscious sedation anaesthesia plus local anaesthesia, and two studies compared general anaesthesia versus local anaesthesia. Of these studies, seven plan to report data on functional outcomes using the modified Rankin Scale, five studies on neurological impairment, six studies on stroke-related mortality, two studies on all intracranial haemorrhage, five studies on target artery revascularisation status, four studies on time to revascularisation, and four studies on adverse events. One ongoing study plans to report data on quality of life. One study did not plan to report any outcome of interest for this review.

AUTHORS' CONCLUSIONS

In early outcomes, general anaesthesia improves target artery revascularisation compared to non-general anaesthesia with moderate-certainty evidence. General anaesthesia may improve adverse events (haemodynamic instability) compared to non-general anaesthesia with low-certainty evidence. We found no evidence of a difference in neurological impairment, stroke-related mortality, all intracranial haemorrhage and haemodynamic instability adverse events between groups with low-certainty evidence. We are uncertain whether general anaesthesia improves functional outcomes and time to revascularisation because the certainty of the evidence is very low. However, regarding long-term outcomes, general anaesthesia makes no difference to functional outcomes compared to non-general anaesthesia with low-certainty evidence. General anaesthesia did not change stroke-related mortality when compared to non-general anaesthesia with low-certainty evidence. There were no reported data for other outcomes. In view of the limited evidence of effect, more randomised controlled trials with a large number of participants and good protocol design with a low risk of bias should be performed to reduce our uncertainty and to aid decision-making in the choice of anaesthesia.

Local versus general anaesthesia for carotid endarterectomy

BACKGROUND

Carotid endarterectomy may significantly reduce the risk of stroke in people with recently symptomatic, severe carotid artery stenosis. However, there are significant perioperative risks that may be minimised by performing the operation under local rather than general anaesthetics. This is an update of a Cochrane Review first published in 1996, and previously updated in 2004, 2008, and 2013.

OBJECTIVES

To determine whether carotid endarterectomy under local anaesthetic: 1) reduces the risk of perioperative stroke and death compared with general anaesthetic; 2) reduces the complication rate (other than stroke) following carotid endarterectomy; and 3) is acceptable to individuals and surgeons.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, and two trials registers (to February 2021). We also reviewed reference lists of articles identified.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing the use of local anaesthetics to general anaesthetics for people having carotid endarterectomy were eligible.

DATA COLLECTION AND ANALYSIS

Three review authors independently extracted data, assessed risk of bias, and evaluated quality of evidence using the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) tool. We calculated a pooled Peto odds ratio (OR) and corresponding 95% confidence interval (CI) for the following outcomes that occurred within 30 days of surgery: stroke, death, ipsilateral stroke, stroke or death, myocardial infarction, local haemorrhage, and arteries shunted.

MAIN RESULTS

We included 16 RCTs involving 4839 participants, of which 3526 were obtained from the single largest trial (GALA). The main findings from our meta-analysis showed that, within 30 days of operation, neither incidence of stroke nor death were significantly different between local and general anaesthesia. Of these, the incidence of stroke in the local and general anaesthesia groups was 3.2% and 3.5%, respectively (Peto odds ratio (OR) 0.91, 95% confidence interval (CI) 0.66 to 1.26; P = 0.58; 13 studies, 4663 participants; low-quality evidence). The rate of ipsilateral stroke under both types of anaesthesia was 3.1% (Peto OR 1.03, 95% CI 0.71 to 1.48; P = 0.89; 2 studies, 3733 participants; low-quality evidence). The incidence of stroke or death in the local anaesthesia group was 3.5%, while stroke or death incidence was 4.1% in the general anaesthesia group (Peto OR 0.85, 95% CI 0.62 to 1.16; P = 0.31; 11 studies, 4391 participants; low-quality evidence). A lower rate of death was observed in the local anaesthetic group but evidence was of low quality (Peto OR 0.61, 95% CI 0.35 to 1.06; P = 0.08; 12 studies, 4421 participants).

AUTHORS' CONCLUSIONS

The incidence of stroke and death were not convincingly different between local and general anaesthesia for people undergoing carotid endarterectomy. The current evidence supports the choice of either approach. Further high-quality studies are still needed as the evidence is of limited reliability.

General Anesthesia Versus Local Anesthesia in Carotid Endarterectomy: A Systematic Review and Meta-Analysis

OBJECTIVE

The choice of anesthetic technique in carotid endarterectomy (CEA) has been controversial. This study compared the outcomes of general anesthesia (GA) and local anesthesia (LA) in CEA.

DESIGN

Systematic review and meta-analysis of comparative studies.

SETTING

Hospitals.

PARTICIPANTS

Adult patients undergoing CEA with either LA or GA.

INTERVENTIONS

The effects of GA and LA on CEA outcomes were compared.

MEASUREMENTS AND MAIN RESULTS

PubMed, OVID, Scopus, and Embase were searched to June 2018. Thirty-one studies with 152,376 patients were analyzed. A random effect model was used, and heterogeneity was assessed with the I² and chi-square tests. LA was associated with shorter surgical time (weighted mean difference -9.15 min [-15.55 to -2.75]; p = 0.005) and less stroke (odds ratio [OR] 0.76 [0.62-0.92]; p = 0.006), cardiac complications (OR 0.59 [0.47-0.73]; p < 0.00001), and in-hospital mortality (OR 0.72 [0.59-0.90]; p = 0.003). Transient neurologic deficit rates were similar (OR 0.69 [0.46-1.04]; p = 0.07). Heterogeneity was significant for surgical time (I² = 0.99, chi-square = 1,336.04; p < 0.00001), transient neurologic deficit (I² = 0.41, chi-square = 28.81; p = 0.04), and cardiac complications (I² = 0.42, chi-square = 43.32; p = 0.01) but not for stroke (I² = 0.22, chi-square = 30.72; p = 0.16) and mortality (I² = 0.00, chi-square = 21.69; p = 0.65). Randomized controlled trial subgroup analysis was performed, and all the aforementioned variables were not significantly different or heterogenous.

CONCLUSION

The results from this study showed no inferiority of using LA to GA in patients undergoing CEA. Future investigations should be reported more systematically, preferably with randomization or propensity-matched analysis, and thus registries will facilitate investigation of this subject. Anesthetic choice in CEA should be individualized and encouraged where applicable.

Anesthetic Considerations for Carotid Endarterectomy: A Postgraduate Educational Review

Carotid endarterectomy (CEA) has shown a significant benefit in preventing ipsilateral stroke when it is compared to conservative management. Surgical morbidity and mortality must be kept to a minimum to achieve this benefit. Neurological status of the CEA patients can be monitored easily during regional anesthesia depending on the awake testing (neurocognitive assessment) method of the CEA patients. In addition, specific parameters can help us to monitor and to predict the neurological status of the CEA patients during the procedures such as regional cerebral oxygen saturation (rSO₂) and middle cerebral artery velocity (MCAv) changes. We conducted a computerized literature search involving humans, published in English until December 2017, and indexed through Medical Databases; MEDLINE/PubMed, EMBASE, and Web of Science. We reviewed articles performed for prospective and other types of studies related to CEA procedures and techniques which can predict patient's status during the procedure. Searching relevant articles and discussing the results to allow meaningful rate comparison, and to conclude a result view which benefits the CEA patients and the medical staff during the CEA procedures. In total, studies observed cerebral rSO₂ and MCAv have significant value during CEA procedures. Patients with neurological symptoms during the procedures showed changes of cerebral rSO₂ and MCAv more than the patients without neurological symptoms. Mentioned parameters (cerebral rSO₂ and MCAv) showed significant increasing right after the procedure. Mostly, CEA surgeries under local anesthesia were observed, for monitoring patients' consciousness status and comparing it to patients who undergo general anesthesia, to view the reliability of these techniques during CEA procedures, and to predict and avoid intraoperative neurological symptoms.

Practical Use of Near-Infrared Spectroscopy in Carotid Surgery

Carotid endarterectomy (CEA) is the gold standard for the treatment of symptomatic patients with atherosclerotic carotid disease. However, benefit of the CEA procedure depends on the rate of peri- and postoperative adverse neurological events. Therefore, brain monitoring is important in detecting cerebral ischemia during and after CEA and also allows to prompt appropriate action. Traditional methods of cerebral monitoring are being replaced by novel, easy-to-use techniques that allow continued monitoring of regional cerebral oxygen saturation. In this review, we present the recent literature data related to the mechanism of cerebral oximetry and its practical use during and after CEA.

Intraoperative management of carotid endarterectomy

First reports on surgical treatment of cerebrovascular atherosclerosis date to the early 1950s. With advancements in surgical technique, carotid endarterectomy (CEA) has become the treatment of choice for patients with both symptomatic and asymptomatic severe carotid stenosis. Given the benefits that surgery offers beyond medical management, the number of CEA procedures continues to increase. The intraoperative management of patients undergoing CEA is challenging because of the combination of patient and surgical factors. This article explores and reviews the literature on anesthetic management and considerations of patients undergoing CEA.

Systematic review of near-infrared spectroscopy determined cerebral oxygenation during non-cardiac surgery

Near-infrared spectroscopy (NIRS) is used to monitor regional cerebral oxygenation (rScO₂) during cardiac surgery but is less established during non-cardiac surgery. This systematic review aimed (i) to determine the non-cardiac surgical procedures that provoke a reduction in rScO₂ and (ii) to evaluate whether an intraoperative reduction in rScO₂ influences postoperative outcome. The PubMed and Embase database were searched from inception until April 30, 2013 and inclusion criteria were intraoperative NIRS determined rScO₂ in adult patients undergoing non-cardiac surgery. The type of surgery and number of patients included were recorded. There was included 113 articles and evidence suggests that rScO₂ is reduced during thoracic surgery involving single lung ventilation, major abdominal surgery, hip surgery, and laparoscopic surgery with the patient placed in anti-Tredelenburg's position. Shoulder arthroscopy in the beach chair and carotid endarterectomy with clamped internal carotid artery (ICA) also cause pronounced cerebral desaturation. A >20% reduction in rScO₂ coincides with indices of regional and global cerebral ischemia during carotid endarterectomy. Following thoracic surgery, major orthopedic, and abdominal surgery the occurrence of postoperative cognitive dysfunction (POCD) might be related to intraoperative cerebral desaturation. In conclusion, certain non-cardiac surgical procedures is associated with an increased risk for the occurrence of rScO₂. Evidence for an association between cerebral desaturation and postoperative outcome parameters other than cognitive dysfunction needs to be established.

Local versus general anaesthesia for carotid endarterectomy

BACKGROUND

Carotid endarterectomy may significantly reduce the risk of stroke in people with recently symptomatic, severe carotid artery stenosis. However, there are significant perioperative risks that may be reduced by performing the operation under local rather than general anaesthetic. This is an update of a Cochrane Review first published in 1996, and previously updated in 2004 and 2008.

OBJECTIVES

To determine whether carotid endarterectomy under local anaesthetic: (1) reduces the risk of perioperative stroke and death compared with general anaesthetic; (2) reduces the complication rate (other than stroke) following carotid endarterectomy; and (3) is acceptable to patients and surgeons.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (September 2013), MEDLINE (1966 to September 2013), EMBASE (1980 to September 2013) and Index to Scientific and Technical Proceedings (ISTP) (1980 to September 2013). We also handsearched relevant journals, and searched the reference lists of articles identified.

SELECTION CRITERIA

Randomised trials comparing the use of local anaesthetic to general anaesthetic for carotid endarterectomy were considered for inclusion.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed trial quality and extracted data. We calculated a pooled Peto odds ratio (OR) and corresponding 95% confidence interval (CI) for the following outcomes that occurred within 30 days of surgery: stroke, death, stroke or death, myocardial infarction, local haemorrhage, cranial nerve injuries, and shunted arteries.

MAIN RESULTS

We included 14 randomised trials involving 4596 operations, of which 3526 were from the single largest trial (GALA). In general, reporting of methodology in the included studies was poor. All studies were unable to blind patients and surgical teams to randomised treatment allocation and for most studies the blinding of outcome assessors was unclear. There was no statistically significant difference in the incidence of stroke within 30 days of surgery between the local anaesthesia group and the general anaesthesia group. The incidence of strokes in the local anaesthesia group was 3.2% compared to 3.5% in the general anaesthesia group (Peto OR 0.92, 95% CI 0.67 to 1.28). There was no statistically significant difference in the proportion of patients who had a stroke or died within 30 days of surgery. In the local anaesthesia group 3.6% of patients had a stroke or died compared to 4.2% of patients in the general anaesthesia group (Peto OR 0.85, 95% CI 0.63 to 1.16). There was a non-significant trend towards lower operative mortality with local anaesthetic. In the local anaesthesia group 0.9% of patients died within 30 days of surgery compared to 1.5% of patients in the general anaesthesia group (Peto OR 0.62, 95% CI 0.36 to 1.07). However, neither the GALA trial or the pooled analysis were adequately powered to reliably detect an effect on mortality.

AUTHORS' CONCLUSIONS

The proportion of patients who had a stroke or died within 30 days of surgery did not differ significantly between the two types of anaesthetic techniques used during carotid endarterectomy. This systematic review provides evidence to suggest that patients and surgeons can choose either anaesthetic technique, depending on the clinical situation and their own preferences.

[Intraoperative electrophysiological monitoring with evoked potentials]

During the last 30 years intraoperative electrophysiological monitoring (IOEM) has gained increasing importance in monitoring the function of neuronal structures and the intraoperative detection of impending new neurological deficits. The use of IOEM could reduce the incidence of postoperative neurological deficits after various surgical procedures. Motor evoked potentials (MEP) seem to be superior to other methods for many indications regarding monitoring of the central nervous system. During the application of IOEM general anesthesia should be provided by total intravenous anesthesia with propofol with an emphasis on a continuous high opioid dosage. When intraoperative MEP or electromyography guidance is planned, muscle relaxation must be either completely omitted or maintained in a titrated dose range in a steady state. The IOEM can be performed by surgeons, neurologists and neurophysiologists or increasingly more by anesthesiologists. However, to guarantee a safe application and interpretation, sufficient knowledge of the effects of the surgical procedure and pharmacological and physiological influences on the neurophysiological findings are indispensable.