E Editorial
Monitoring for Carotid Endarterectomy: More or Less? Arthur M. Lam, MD, FRCPC, FNCS,*† and Daniel Kianpour, MD*
C
arotid endarterectomy (CEA) is one of the most frequently performed surgical procedures. Its efficacy in preventing the occurrence of stroke in patients with symptomatic carotid stenosis has been repeatedly confirmed in large clinical trials, notably North American Symptomatic Carotid Endarterectomy Trial (NASCET)1 and European Carotid Surgery Trial.2 Ironically, the very procedure performed to prevent stroke can cause stroke itself. In general, for symptomatic patients, a perioperative stroke rate should be ≤4%, and for asymptomatic patients, should be considerably less, or 14 times more likely to have intraoperative changes.10 What Malcharek et al. attempt to do is to improve the predictive value of SSEP (both median and tibial nerves) monitoring with the addition of transcranial motor-evoked potential (tcMEP). In a multicenter study, the authors had previously published a similar article with tcMEP but only median SSEP.11 As in the previous study, this is not a comparative study between SSEP and tcMEP monitoring, but rather an observational audit where all 264 patients were monitored with both modalities (successful in 241). Shunting was based on changes in any monitoring modality. Overall, 15 patients required shunting. Eleven patients had transient deficits while 1 patient suffered a permanent deficit. These data do not allow the authors to determine the relative sensitivity or specificity of each modality because it is apparent that each modality is associated with false negatives. The authors rightfully conclude that tcMEP is feasible and may complement SSEP monitoring. Before one rushes to implement tcMEP monitoring, one needs to place the entire concept of monitoring for CEA in perspective.
INTRAOPERATIVE MONITORS TO DETECT CEREBRAL ISCHEMIA
Intraoperative monitors used to determine adequacy of cerebral circulation can be classified into 3 categories: cerebral function, cerebral blood flow/flow surrogate, or metabolism (oxygen supply/demand). These are summarized in Table 1. Some centers used a combination of monitors to improve sensitivity and specificity,7,12 and a recent metaanalysis suggests that a combination of monitors from 2 different categories may be optimal.13 June 2015 • Volume 120 • Number 6
Copyright © 2015 International Anesthesia Research Society. Unauthorized reproduction of this article is prohibited.
Monitoring for Carotid Endarterectomy: More or Less?
Table 1. Monitoring Modalities for Carotid Endarterectomy Cerebral function Neurologic function (awake)14 16-Channel EEG18
Cerebral blood flow Transcranial Doppler7,15 Stump pressure6
Processed EEG21
Xenon133 CBF22
Cerebral metabolism Cerebral oximetry16,17 Jugular bulb venous oximetry19,20 Conjunctival oxygen tension23
SSEP9,10 MEP8 EEG = electroencephalography; SSEP = somatosensory-evoked potentials; MEP = motor-evoked potential; CBF = cerebral blood flow.
The literature does not provide any guidance regarding the best surgical approach. Favorable results have been reported with all 3 surgical approaches: nonshunting, routine shunting, and selective shunting.24,25 No randomized controlled trials or comparative effectiveness research has been conducted on the surgical approach, let alone the most cost-effective monitor modality or monitor modality combinations. Nevertheless, it makes physiologic sense to choose the selective shunting approach, performing an invasive procedure with inherent risks only in patients identified to be at risk for cerebral hypoperfusion during cross-clamp. The question then becomes: what is the appropriate modality to choose and what to monitor? The ideal monitor should have high sensitivity and specificity, be easy to interpret, and, more importantly, provide real-time information with a sufficient therapeutic time window to allow treatment implementation to alter outcome. In the NASCET trial,1 now dated and not conducted to assess the effectiveness of monitoring, only 51% of the patients in the trial were monitored, the majority of whom with unprocessed EEG. In this issue of the journal, the authors8 have added tcMEP to SSEP and demonstrated that there may be an improvement in sensitivity. However, the number of patients with changes is small, and had this been a randomized trial, the results would not withstand statistical scrutiny. Moreover, there is no real gold standard in cerebral monitoring for CEA. One could argue that monitoring neurologic function in the awake patient is the gold standard, but this would only be applicable when regional anesthesia is used. With general anesthesia, based on NASCET data, one would consider EEG monitoring as the gold standard, thus the comparative research that would prove that motor-evoked potential is indeed useful has not yet been done. In fact, a recent study concludes that motor-evoked potential added to SSEP and EEG provides no additional value.26
TO MONITOR OR NOT MONITOR
A broader question beyond the type of monitor is whether we should be monitoring at all. As mentioned above, the literature does not provide any guidance. However, we can assess the relative importance of intraoperative cerebral monitoring from the perspective of perioperative stroke after CEA. The causes of perioperative stroke from CEA can be either ischemic or embolic27 and rarely from postoperative intracranial hemorrhage.28 Based on imaging studies
June 2015 • Volume 120 • Number 6
(watershed versus major arterial distribution), it is estimated that the majority of perioperative strokes after CEA are embolic in nature (about 2/3).27,29 Although NASCET did not examine the etiology of stroke, the timing of the occurrence of the strokes corresponds with this estimate because the majority of the strokes did not occur intraoperatively.1 Of all the monitors listed, only the transcranial Doppler can monitor emboli and hyperperfusion syndrome and, to be effective, would have to continue beyond the intraoperative to the postoperative period, a labor-intensive and costly proposition. Thus, the perfect intraoperative cerebral monitor would at best prevent 1/3 of the perioperative strokes. This is not to undermine the potential importance of intraoperative monitoring, not the least of which includes obviation of arbitrary increase in blood pressure during cross-clamp, but to put it into the proper context of perioperative stroke. Perhaps we should take a step back and ask the question: Does monitoring make a difference in outcome? We really do not have the answer, but we can glean some insight from the results of the General Anesthesia versus Local Anesthesia for carotid surgery (GALA) trial comparing local or regional anesthesia to general anesthesia.30 As mentioned above, monitoring neurologic function under regional anesthesia is arguably the gold standard for monitoring because it has high specificity as a shunt indicator. It is telling that the shunt rate is always lower in CEA performed under regional anesthesia compared with general anesthesia, as demonstrated in the GALA trial, as well as in other studies.14,30 These considerations confer theoretical advantages to the regional anesthesia technique and are the reasons why many surgeons favor this approach. Yet the GALA trial could not demonstrate a significant difference in outcome between these 2 groups. Given the low stroke rate, the GALA trial may be underpowered to detect a difference, despite the enrollment of 3526 patients. Nevertheless, this lack of difference indirectly suggests that intraoperative cerebral monitoring may be overrated. There are, however, potentially confounding factors in addition to being underpowered. These include (1) cross-clamp ischemia only accounts for a small percentage of the perioperative stroke, consequently reducing this number fails to make a difference in the overall outcome; (2) the advantages gained with the awake monitor may be balanced by the need to hurry or perform a less extensive repair under local anesthesia, relative to a procedure performed under general anesthesia, and the latter may necessitate an intraoperative monitor to determine the need for shunting. These discussions are meant to illustrate the complexity, not obfuscate, the role of intraoperative cerebral monitoring during CEA. The study of Malcharek et al. examines a new piece of this puzzle. What we need is the complete picture! E DISCLOSURES
Name: Arthur M. Lam, MD, FRCPC, FNCS. Contribution: This author helped write the manuscript. Attestation: Arthur M. Lam approved the final manuscript. Name: Daniel Kianpour, MD. Contribution: This author helped write the manuscript. Attestation: Daniel Kianpour approved the final manuscript. This manuscript was handled by: Gregory J. Crosby, MD.
www.anesthesia-analgesia.org 1187
Copyright © 2015 International Anesthesia Research Society. Unauthorized reproduction of this article is prohibited.
E Editorial REFERENCES 1. Barnett HJ, Taylor DW, Eliasziw M, Fox AJ, Ferguson GG, Haynes RB, Rankin RN, Clagett GP, Hachinski VC, Sackett DL, Thorpe KE, Meldrum HE, Spence JD. Benefit of carotid endarterectomy in patients with symptomatic moderate or severe stenosis. North American Symptomatic Carotid Endarterectomy Trial Collaborators. N Engl J Med 1998;339:1415–25 2. European Carotid Surgery Trialists’ Collaborative Group. Randomized trial of endarterectomy for recently symptomatic carotid stenosis: final results of the MRC, European carotid surgery trial (ECST). Lancet 1998;351:1379–87 3. Heyer EJ, Wilson DA, Sahlein DH, Mocco J, Williams SC, Sciacca R, Rampersad A, Komotar RJ, Zurica J, Benvenisty A, Quest DO, Todd G, Solomon RA, Connolly ES Jr. APOE-epsilon4 predisposes to cognitive dysfunction following uncomplicated carotid endarterectomy. Neurology 2005;65:1759–63 4. Halsey JH Jr. Risks and benefits of shunting in carotid endarterectomy. The International Transcranial Doppler Collaborators. Stroke 1992;23:1583–7 5. Reddy K, West M, Anderson B. Carotid endarterectomy without indwelling shunts and intraoperative electrophysiologic monitoring. Can J Neurol Sci 1987;14:131–5 6. Aburahma AF, Stone PA, Hass SM, Dean LS, Habib J, Keiffer T, Emmett M. Prospective randomized trial of routine versus selective shunting in carotid endarterectomy based on stump pressure. J Vasc Surg 2010;51:1133–8 7. Moritz S, Kasprzak P, Arit M, Taeger K, Metz C. Accuracy of cerebral monitoring in detecting cerebral ischemia during carotid endarterectomy. Anesthesiology 2007;107:563–69 8. Malcharek MJ, Kulpok A, Deletis V, Ulkatan S, Sablotzki A, Hennig G, Gille J, Pilge S, Schneider G. Intraoperative multimodal evoked potential monitoring during carotid endarterectomy: a retrospective study of 264 patients. Anesth Analg 2015;120:1352–60 9. Lam AM, Manninen PH, Ferguson GG, Nantau W. Monitoring electrophysiologic function during carotid endarterectomy: a comparison of somatosensory evoked potentials and conventional electroencephalogram. Anesthesiology 1991;75:15–21 10. Nwachuku EL, Balzer JR, Yabes JG, Habeych ME, Crammond DJ, Thirumala PD. Diagnostic value of somatosensory evoked potential changes during carotid endarterectomy: a systematic review and meta-analysis. JAMA Neurol 2015;72:73–80 11. Malcharek MJ, Ulkatan S, Marinò V, Geyer M, Lladó-Carbó E, Perez-Fajardo G, Arranz-Arranz B, Climent J, Aloj F, Franco E, Chiacchiari L, Kulpok A, Sablotzki A, Hennig G, Deletis V. Intraoperative monitoring of carotid endarterectomy by transcranial motor evoked potential: a multicenter study of 600 patients. Clin Neurophysiol 2013;124:1025–30 12. Girn HR, Dellagrammaticas D, Laughlan K, Gough MJ; GALA Trial Collaborators. Carotid endarterectomy: technical practices of surgeons participating in the GALA trial. Eur J Vasc Endovasc Surg 2008;36:385–9 13. Guay J, Kopp S. Cerebral monitors versus regional anesthesia to detect cerebral ischemia in patients undergoing carotid endarterectomy: a meta-analysis. Can J Anaesth 2013;60:266–79 14. Cho J, Lee KK, Yun WS, Kim HK, Hwang YH, Huh S. Selective shunt during carotid endarterectomy using routine awake test with respect to a lower shunt rate. J Korean Surg Soc 2013;84:238–44
1188 www.anesthesia-analgesia.org
15. Spencer MP. Transcranial Doppler monitoring and causes of stroke from carotid endarterectomy. Stroke 1997;28:685–91 16. Espenell AE, McIntyre IW, Gulati H, Girling LG, Wilkinson MF, Silvaggio JA, Koulack J, West M, Harding GE, Kaufmann AM, Mutch WA. Lactate flux during carotid endarterectomy under general anesthesia: correlation with various point-of-care monitors. Can J Anaesth 2010;57:903–12 17. Pennekamp CW, Immink RV, den Ruijter HM, Kappelle LJ, Bots ML, Buhre WF, Moll FL, de Borst GJ. Near-infrared spectroscopy to indicate selective shunt use during carotid endarterectomy. Eur J Vasc Endovasc Surg 2013;46:397–403 18. Tan TW, Garcia-Toca M, Marcaccio EJ Jr, Carney WI Jr, Machan JT, Slaiby JM. Predictors of shunt during carotid endarterectomy with routine electroencephalography monitoring. J Vasc Surg 2009;49:1374–8 19. Niinai H, Nakagawa I, Shima T, Kawamoto M, Yuge O. Continuous monitoring of jugular bulb venous oxygen saturation for evaluation of cerebral perfusion during carotid endarterectomy. Hiroshima J Med Sci 1998;47:133–7 20. Moritz S, Kasprzak P, Woertgen C, Taeger K, Metz C. The accuracy of jugular bulb venous monitoring in detecting cerebral ischemia in awake patients undergoing carotid endarterectomy. J Neurosurg Anesthesiol 2008;20:8–14 21. Minicucci F, Cursi M, Fornara C, Rizzo C, Chiesa R, Tirelli A, Fanelli G, Meraviglia MV, Giacomotti L, Comi G. Computerassisted EEG monitoring during carotid endarterectomy. J Clin Neurophysiol 2000;17:101–7 22. Algotsson L, Messeter K, Rehncrona S, Skeidsvoll H, Ryding E. Cerebral hemodynamic changes and electroencephalography during carotid endarterectomy. J Clin Anesth 1990;2:143–51 23. Kram HB, Shoemaker WC, Bratanow N, Appel PL, Sterling RP, Fleming AW. Noninvasive conjunctival oxygen monitoring during carotid endarterectomy. Arch Surg 1986;121:914–7 24. Aburahma AF, Mousa AY, Stone PA. Shunting during carotid endarterectomy. J Vasc Surg 2011;54:1502–10 25. Chongruksut W, Vaniyapong T, Rerkasem K. Routine or selective carotid artery shunting for carotid endarterectomy (and different methods of monitoring in selective shunting) (review). The Cochrane Collaboration 2014;6:1–45 26. Alcantara SD, Wuamett JC, Lantis JC II, Ulkatan S, Bamberger P, Mendes D, Benvenisty A, Todd G. Outcomes of combined somatosensory evoked potential, motor evoked potential, and electroencephalography monitoring during carotid endarterectomy. Ann Vasc Surg 2014;28:665–72 27. Krul JM, van Gijn J, Ackerstaff RG, Eikelboom BC, Theodorides T, Vermeulen FE. Site and pathogenesis of infarcts associated with carotid endarterectomy. Stroke 1989;20:324–8 28. Pennekamp CW, Moll FL, De Borst GJ. Role of transcranial Doppler in cerebral hyperperfusion syndrome. J Cardiovasc Surg (Torino) 2012;53:765–71 29. Müller M, Reiche W, Langenscheidt P, Hassfeld J, Hagen T. Ischemia after carotid endarterectomy: comparison between transcranial Doppler sonography and diffusion-weighted MR imaging. AJNR Am J Neuroradiol 2000;21:47–54 30. GALA Trial Collaborate Group. General anaesthesia versus local anaesthesia for carotid surgery (GALA): a multicentre, randomized controlled trial. Lancet 2008;372:2132–42
anesthesia & analgesia
Copyright © 2015 International Anesthesia Research Society. Unauthorized reproduction of this article is prohibited.
Monitoring for Carotid Endarterectomy: More or Less? Arthur M. Lam, MD, FRCPC, FNCS,*† and Daniel Kianpour, MD*
C
arotid endarterectomy (CEA) is one of the most frequently performed surgical procedures. Its efficacy in preventing the occurrence of stroke in patients with symptomatic carotid stenosis has been repeatedly confirmed in large clinical trials, notably North American Symptomatic Carotid Endarterectomy Trial (NASCET)1 and European Carotid Surgery Trial.2 Ironically, the very procedure performed to prevent stroke can cause stroke itself. In general, for symptomatic patients, a perioperative stroke rate should be ≤4%, and for asymptomatic patients, should be considerably less, or 14 times more likely to have intraoperative changes.10 What Malcharek et al. attempt to do is to improve the predictive value of SSEP (both median and tibial nerves) monitoring with the addition of transcranial motor-evoked potential (tcMEP). In a multicenter study, the authors had previously published a similar article with tcMEP but only median SSEP.11 As in the previous study, this is not a comparative study between SSEP and tcMEP monitoring, but rather an observational audit where all 264 patients were monitored with both modalities (successful in 241). Shunting was based on changes in any monitoring modality. Overall, 15 patients required shunting. Eleven patients had transient deficits while 1 patient suffered a permanent deficit. These data do not allow the authors to determine the relative sensitivity or specificity of each modality because it is apparent that each modality is associated with false negatives. The authors rightfully conclude that tcMEP is feasible and may complement SSEP monitoring. Before one rushes to implement tcMEP monitoring, one needs to place the entire concept of monitoring for CEA in perspective.
INTRAOPERATIVE MONITORS TO DETECT CEREBRAL ISCHEMIA
Intraoperative monitors used to determine adequacy of cerebral circulation can be classified into 3 categories: cerebral function, cerebral blood flow/flow surrogate, or metabolism (oxygen supply/demand). These are summarized in Table 1. Some centers used a combination of monitors to improve sensitivity and specificity,7,12 and a recent metaanalysis suggests that a combination of monitors from 2 different categories may be optimal.13 June 2015 • Volume 120 • Number 6
Copyright © 2015 International Anesthesia Research Society. Unauthorized reproduction of this article is prohibited.
Monitoring for Carotid Endarterectomy: More or Less?
Table 1. Monitoring Modalities for Carotid Endarterectomy Cerebral function Neurologic function (awake)14 16-Channel EEG18
Cerebral blood flow Transcranial Doppler7,15 Stump pressure6
Processed EEG21
Xenon133 CBF22
Cerebral metabolism Cerebral oximetry16,17 Jugular bulb venous oximetry19,20 Conjunctival oxygen tension23
SSEP9,10 MEP8 EEG = electroencephalography; SSEP = somatosensory-evoked potentials; MEP = motor-evoked potential; CBF = cerebral blood flow.
The literature does not provide any guidance regarding the best surgical approach. Favorable results have been reported with all 3 surgical approaches: nonshunting, routine shunting, and selective shunting.24,25 No randomized controlled trials or comparative effectiveness research has been conducted on the surgical approach, let alone the most cost-effective monitor modality or monitor modality combinations. Nevertheless, it makes physiologic sense to choose the selective shunting approach, performing an invasive procedure with inherent risks only in patients identified to be at risk for cerebral hypoperfusion during cross-clamp. The question then becomes: what is the appropriate modality to choose and what to monitor? The ideal monitor should have high sensitivity and specificity, be easy to interpret, and, more importantly, provide real-time information with a sufficient therapeutic time window to allow treatment implementation to alter outcome. In the NASCET trial,1 now dated and not conducted to assess the effectiveness of monitoring, only 51% of the patients in the trial were monitored, the majority of whom with unprocessed EEG. In this issue of the journal, the authors8 have added tcMEP to SSEP and demonstrated that there may be an improvement in sensitivity. However, the number of patients with changes is small, and had this been a randomized trial, the results would not withstand statistical scrutiny. Moreover, there is no real gold standard in cerebral monitoring for CEA. One could argue that monitoring neurologic function in the awake patient is the gold standard, but this would only be applicable when regional anesthesia is used. With general anesthesia, based on NASCET data, one would consider EEG monitoring as the gold standard, thus the comparative research that would prove that motor-evoked potential is indeed useful has not yet been done. In fact, a recent study concludes that motor-evoked potential added to SSEP and EEG provides no additional value.26
TO MONITOR OR NOT MONITOR
A broader question beyond the type of monitor is whether we should be monitoring at all. As mentioned above, the literature does not provide any guidance. However, we can assess the relative importance of intraoperative cerebral monitoring from the perspective of perioperative stroke after CEA. The causes of perioperative stroke from CEA can be either ischemic or embolic27 and rarely from postoperative intracranial hemorrhage.28 Based on imaging studies
June 2015 • Volume 120 • Number 6
(watershed versus major arterial distribution), it is estimated that the majority of perioperative strokes after CEA are embolic in nature (about 2/3).27,29 Although NASCET did not examine the etiology of stroke, the timing of the occurrence of the strokes corresponds with this estimate because the majority of the strokes did not occur intraoperatively.1 Of all the monitors listed, only the transcranial Doppler can monitor emboli and hyperperfusion syndrome and, to be effective, would have to continue beyond the intraoperative to the postoperative period, a labor-intensive and costly proposition. Thus, the perfect intraoperative cerebral monitor would at best prevent 1/3 of the perioperative strokes. This is not to undermine the potential importance of intraoperative monitoring, not the least of which includes obviation of arbitrary increase in blood pressure during cross-clamp, but to put it into the proper context of perioperative stroke. Perhaps we should take a step back and ask the question: Does monitoring make a difference in outcome? We really do not have the answer, but we can glean some insight from the results of the General Anesthesia versus Local Anesthesia for carotid surgery (GALA) trial comparing local or regional anesthesia to general anesthesia.30 As mentioned above, monitoring neurologic function under regional anesthesia is arguably the gold standard for monitoring because it has high specificity as a shunt indicator. It is telling that the shunt rate is always lower in CEA performed under regional anesthesia compared with general anesthesia, as demonstrated in the GALA trial, as well as in other studies.14,30 These considerations confer theoretical advantages to the regional anesthesia technique and are the reasons why many surgeons favor this approach. Yet the GALA trial could not demonstrate a significant difference in outcome between these 2 groups. Given the low stroke rate, the GALA trial may be underpowered to detect a difference, despite the enrollment of 3526 patients. Nevertheless, this lack of difference indirectly suggests that intraoperative cerebral monitoring may be overrated. There are, however, potentially confounding factors in addition to being underpowered. These include (1) cross-clamp ischemia only accounts for a small percentage of the perioperative stroke, consequently reducing this number fails to make a difference in the overall outcome; (2) the advantages gained with the awake monitor may be balanced by the need to hurry or perform a less extensive repair under local anesthesia, relative to a procedure performed under general anesthesia, and the latter may necessitate an intraoperative monitor to determine the need for shunting. These discussions are meant to illustrate the complexity, not obfuscate, the role of intraoperative cerebral monitoring during CEA. The study of Malcharek et al. examines a new piece of this puzzle. What we need is the complete picture! E DISCLOSURES
Name: Arthur M. Lam, MD, FRCPC, FNCS. Contribution: This author helped write the manuscript. Attestation: Arthur M. Lam approved the final manuscript. Name: Daniel Kianpour, MD. Contribution: This author helped write the manuscript. Attestation: Daniel Kianpour approved the final manuscript. This manuscript was handled by: Gregory J. Crosby, MD.
www.anesthesia-analgesia.org 1187
Copyright © 2015 International Anesthesia Research Society. Unauthorized reproduction of this article is prohibited.
E Editorial REFERENCES 1. Barnett HJ, Taylor DW, Eliasziw M, Fox AJ, Ferguson GG, Haynes RB, Rankin RN, Clagett GP, Hachinski VC, Sackett DL, Thorpe KE, Meldrum HE, Spence JD. Benefit of carotid endarterectomy in patients with symptomatic moderate or severe stenosis. North American Symptomatic Carotid Endarterectomy Trial Collaborators. N Engl J Med 1998;339:1415–25 2. European Carotid Surgery Trialists’ Collaborative Group. Randomized trial of endarterectomy for recently symptomatic carotid stenosis: final results of the MRC, European carotid surgery trial (ECST). Lancet 1998;351:1379–87 3. Heyer EJ, Wilson DA, Sahlein DH, Mocco J, Williams SC, Sciacca R, Rampersad A, Komotar RJ, Zurica J, Benvenisty A, Quest DO, Todd G, Solomon RA, Connolly ES Jr. APOE-epsilon4 predisposes to cognitive dysfunction following uncomplicated carotid endarterectomy. Neurology 2005;65:1759–63 4. Halsey JH Jr. Risks and benefits of shunting in carotid endarterectomy. The International Transcranial Doppler Collaborators. Stroke 1992;23:1583–7 5. Reddy K, West M, Anderson B. Carotid endarterectomy without indwelling shunts and intraoperative electrophysiologic monitoring. Can J Neurol Sci 1987;14:131–5 6. Aburahma AF, Stone PA, Hass SM, Dean LS, Habib J, Keiffer T, Emmett M. Prospective randomized trial of routine versus selective shunting in carotid endarterectomy based on stump pressure. J Vasc Surg 2010;51:1133–8 7. Moritz S, Kasprzak P, Arit M, Taeger K, Metz C. Accuracy of cerebral monitoring in detecting cerebral ischemia during carotid endarterectomy. Anesthesiology 2007;107:563–69 8. Malcharek MJ, Kulpok A, Deletis V, Ulkatan S, Sablotzki A, Hennig G, Gille J, Pilge S, Schneider G. Intraoperative multimodal evoked potential monitoring during carotid endarterectomy: a retrospective study of 264 patients. Anesth Analg 2015;120:1352–60 9. Lam AM, Manninen PH, Ferguson GG, Nantau W. Monitoring electrophysiologic function during carotid endarterectomy: a comparison of somatosensory evoked potentials and conventional electroencephalogram. Anesthesiology 1991;75:15–21 10. Nwachuku EL, Balzer JR, Yabes JG, Habeych ME, Crammond DJ, Thirumala PD. Diagnostic value of somatosensory evoked potential changes during carotid endarterectomy: a systematic review and meta-analysis. JAMA Neurol 2015;72:73–80 11. Malcharek MJ, Ulkatan S, Marinò V, Geyer M, Lladó-Carbó E, Perez-Fajardo G, Arranz-Arranz B, Climent J, Aloj F, Franco E, Chiacchiari L, Kulpok A, Sablotzki A, Hennig G, Deletis V. Intraoperative monitoring of carotid endarterectomy by transcranial motor evoked potential: a multicenter study of 600 patients. Clin Neurophysiol 2013;124:1025–30 12. Girn HR, Dellagrammaticas D, Laughlan K, Gough MJ; GALA Trial Collaborators. Carotid endarterectomy: technical practices of surgeons participating in the GALA trial. Eur J Vasc Endovasc Surg 2008;36:385–9 13. Guay J, Kopp S. Cerebral monitors versus regional anesthesia to detect cerebral ischemia in patients undergoing carotid endarterectomy: a meta-analysis. Can J Anaesth 2013;60:266–79 14. Cho J, Lee KK, Yun WS, Kim HK, Hwang YH, Huh S. Selective shunt during carotid endarterectomy using routine awake test with respect to a lower shunt rate. J Korean Surg Soc 2013;84:238–44
1188 www.anesthesia-analgesia.org
15. Spencer MP. Transcranial Doppler monitoring and causes of stroke from carotid endarterectomy. Stroke 1997;28:685–91 16. Espenell AE, McIntyre IW, Gulati H, Girling LG, Wilkinson MF, Silvaggio JA, Koulack J, West M, Harding GE, Kaufmann AM, Mutch WA. Lactate flux during carotid endarterectomy under general anesthesia: correlation with various point-of-care monitors. Can J Anaesth 2010;57:903–12 17. Pennekamp CW, Immink RV, den Ruijter HM, Kappelle LJ, Bots ML, Buhre WF, Moll FL, de Borst GJ. Near-infrared spectroscopy to indicate selective shunt use during carotid endarterectomy. Eur J Vasc Endovasc Surg 2013;46:397–403 18. Tan TW, Garcia-Toca M, Marcaccio EJ Jr, Carney WI Jr, Machan JT, Slaiby JM. Predictors of shunt during carotid endarterectomy with routine electroencephalography monitoring. J Vasc Surg 2009;49:1374–8 19. Niinai H, Nakagawa I, Shima T, Kawamoto M, Yuge O. Continuous monitoring of jugular bulb venous oxygen saturation for evaluation of cerebral perfusion during carotid endarterectomy. Hiroshima J Med Sci 1998;47:133–7 20. Moritz S, Kasprzak P, Woertgen C, Taeger K, Metz C. The accuracy of jugular bulb venous monitoring in detecting cerebral ischemia in awake patients undergoing carotid endarterectomy. J Neurosurg Anesthesiol 2008;20:8–14 21. Minicucci F, Cursi M, Fornara C, Rizzo C, Chiesa R, Tirelli A, Fanelli G, Meraviglia MV, Giacomotti L, Comi G. Computerassisted EEG monitoring during carotid endarterectomy. J Clin Neurophysiol 2000;17:101–7 22. Algotsson L, Messeter K, Rehncrona S, Skeidsvoll H, Ryding E. Cerebral hemodynamic changes and electroencephalography during carotid endarterectomy. J Clin Anesth 1990;2:143–51 23. Kram HB, Shoemaker WC, Bratanow N, Appel PL, Sterling RP, Fleming AW. Noninvasive conjunctival oxygen monitoring during carotid endarterectomy. Arch Surg 1986;121:914–7 24. Aburahma AF, Mousa AY, Stone PA. Shunting during carotid endarterectomy. J Vasc Surg 2011;54:1502–10 25. Chongruksut W, Vaniyapong T, Rerkasem K. Routine or selective carotid artery shunting for carotid endarterectomy (and different methods of monitoring in selective shunting) (review). The Cochrane Collaboration 2014;6:1–45 26. Alcantara SD, Wuamett JC, Lantis JC II, Ulkatan S, Bamberger P, Mendes D, Benvenisty A, Todd G. Outcomes of combined somatosensory evoked potential, motor evoked potential, and electroencephalography monitoring during carotid endarterectomy. Ann Vasc Surg 2014;28:665–72 27. Krul JM, van Gijn J, Ackerstaff RG, Eikelboom BC, Theodorides T, Vermeulen FE. Site and pathogenesis of infarcts associated with carotid endarterectomy. Stroke 1989;20:324–8 28. Pennekamp CW, Moll FL, De Borst GJ. Role of transcranial Doppler in cerebral hyperperfusion syndrome. J Cardiovasc Surg (Torino) 2012;53:765–71 29. Müller M, Reiche W, Langenscheidt P, Hassfeld J, Hagen T. Ischemia after carotid endarterectomy: comparison between transcranial Doppler sonography and diffusion-weighted MR imaging. AJNR Am J Neuroradiol 2000;21:47–54 30. GALA Trial Collaborate Group. General anaesthesia versus local anaesthesia for carotid surgery (GALA): a multicentre, randomized controlled trial. Lancet 2008;372:2132–42
anesthesia & analgesia
Copyright © 2015 International Anesthesia Research Society. Unauthorized reproduction of this article is prohibited.
