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353

Cervical epidural Francis Bonnet MD,* Jean Paul Derosier MD,'i" anaesthesia for carotid Frederic Pluskwa MD,* Kou Abhay MD,* A. Gaillard MDt artery surgery

A series of 394 patients (251 men, 143 women; mean age 70.0 +- C2 d D4-D8 a ainsi dtd obtenu. Les patients sont restds dveillds 8.4 yr) selected for carotid artery" surgery, (CAS) performed pendant la durde de l'acte opdratoire dans des conditions de under cervical epidural anaesthesia (CEA ) was analysed retro- confort acceptables. Les complications sdrieuses rencontrdes spectively. Carotid was performed in 326 ont dtd la survenue d'une brdche duremdrienne dans deux cas, patients and saphenous bypass in 68. The cervical epidural d'une brdche vasculaire dans six cas et d'une insuffisance administration of 15 ml 0.5 per cent bupivacaine or 0.37-0.40 respiratoire chez trois patients. Hypotension (10,9 pour cent et per cent bupivacaine plus fentanyl (50-100 Izg) resulted in an bradycardie (2,8 pour cent) dtaient les effets secondaires les effective sensory blockade from C2 to T4-Ts. Patients were plus frdquemment observds. Un accident neurologique transi- maintained awake during the surgical procedure in comfortable toire s'est produit chez 84 patients pendant I'intervention condition. Serious complications included dural puncture in two chirugicale. Un accident neurologique irrdversible est survenu patients, epidural venipuncture in six patients and respiratory chez 12 patients. Trois infarctus du myocarde ont dtE diagnos- muscle paralysis in three patients. Hypotension (10.9 per cent) tiquds dans les suites opdratoires. La mortalitE de cette sdrie and bradycardia (2.8 per cent) were the most frequent side- Eta# de 2,3 pour cent. L'anesthdsie pdridurale cervicale effects of CEA. Transient neurological events were noticed in 84 apparaft comme une alternative possible pour la chirurgie patients during the surgical procedure. A definite neurological carotidienne qui rEclame de toutes faf.ons une surveillance deficit occurred postoperatively in 12 patients. Three patients h~modynamique serrde. suffered postoperative myocardial infarction. The mortality rate was 2.3 per cent (nine patients). Carotid artery surgery may" be performed under CEA but haemodynamic variables shouM be Carotid artery surgery (CAS) is one of the most common monitored closely and managed closely during the procedure. vascular surgical procedures. It is performed under either general or regional anaesthesia. 1,2 Regional anaesthesia Une dtude retrospective a did effectude sur une sdrie de 394 allows simple and reliable monitoring of cerebral function patients (251 hommes, 143 femmes, d'dge moyen 70,0 +- 8,4 during the procedure by means of verbal communication ans) opdrds de la carotide sous anesthdsie pdridurale cervicale. with the patient and frequent evaluation of motor Trois cent vingt six patients ont subi une endartdriectomie strength. 1,2 Two different techniques can be used for carotidienne et 68 un pontage carotidien. L'anesthdsie pEridu- regional anaesthesia of the neck: cervical block or cervical rale a dtd effectude avec de la bupivacaine gt 0,5 pour cent (49 epidural anaesthesia (CEA). Deep cervical block requires patients) puis 0,37-0,40 pour cent (345 patients) (15 ml) identification of the second, third and sometimes the associde d du fentanyl (50-100 lzg). Un bloc sensitif dtendu de fourth cervical nerve roots on the same side as the surgical field. Moreover, a superficial block must be performed because of frequent cutaneous sensory anastomoses with some branches of the lower cervical plexus and of the Key words trigeminal nerve. Though appealingly simple the cervical ANAESTHESIA: vascular; block has a failure rate of nearly 20 per cent when ANAESTHETIC TECHNIQUES: epidural, cervical; performed by the classical approach) Anatomical diffi- ANAESTHETICS, LOCAL: bupivacaine; culties may be encountered especially in obese patients 8RAIN: blood flow; with a short neck. SURGERY: carotid artery surgery. Cervical epidural anaesthesia (CEA), first described by From the Departement d'Anesthdsie,* Hopital Henri Mondor, Dogliotti in 19334 for thoracic surgery, is used mainly for Creteil and the Service d'Anesthrsie,i" Clinique Poirier, relief of chronic in the head and neck or Chambery. due to Pancoast syndrome. 5 In only one previous report Address correspondence to: Dr. F. Bonnet, Departement has CEA been described as an anaesthetic technique d'Anesthrsie, 51, avenue du marechal de Lattre de Tassigny, suitable for CAS. 6 In our institution we chose regional 94000 Creteil, France. anaesthesia for CAS and selected CEA because of the

CAN J ANAESTH 1990/ 37: 3/pp. 353-8 354 CANADIAN JOURNAL OF ANAESTHESIA

familiarity of our anaesthetic team with this technique for momanometer (dynamap | or via a radial artery catheter. chronic pain relief. In the present study we report four Patients were carefully observed for changes in cerebral years' experience of CEA and discuss its advantages and function as evidenced by loss of consciousness, somnol- drawbacks. ence, and neurological deficit of the hand and the . Ephedrine 3 to 6 mg was injected IV when systolic arterial Methods pressure decreased more than 30 per cent of the pre- anaesthetic value or to less than 95 mmHg or when Patients neurological symptoms developed during carotid artery From 1984 to 1988,394 consecutive patients submitted to clamping, associated with a decrease in blood pressure. CAS in our institution were operated upon with CEA after Decreases in heart rate to less than 45 beats min -I were they had given their informed consent and were included treated with IV atropine. , 50 to 70 u. kg -I, was in this study retrospectively. Non-cooperative patients IV injected before carotid artery clamping. and patients who received heparin before surgery were excluded from receiving CEA. Antihypertensive drugs, Postoperative care betablocking adrenergic agents and calcium channel Blood pressure and heart rate were monitored every five blockers were continued until the morning of the opera- minutes with a sphygmomanometer or continuously with tion. Flunitrazepam, 1 mg, was given orally as premedi- a radial artery catheter, during the first 24 hr postopera- cation two hours before surgery. tively. Acute hypertension was treated with calcium channel blockers (10 mg, sublingual nifedipine or 1 v,g" Anaesthetic technique kg- i. h- ~IV nicardipine) and hypotension with ephedrine Patients were placed in the sitting position with the head in IV boli or continuous infusion. The epidural catheter flexed and resting on the thorax, in order to open the was withdrawn in the recovery room when activated lowest cervical interspaces. The spinous process of C7, time was normal. Electrocardiogram and which is horizontal in this position, was easily identified. myocardial enzymes were obtained during the three first An 18-gauge Tuohy needle was inserted by a midline postoperative days and at the end of the hospital stay. approach into the C6-C 7 or C7-TI interspace after Postoperative myocardial infarction was defined by new cutaneous local anaesthesia. The epidural space was Q waves on the ECG and an increase in CK-MB greater identified by aspiration of a saline solution drop hanging than 50E -3 iu mi -~. at the needle base. Careful aspiration ensured that the needle had not entered the subarachnoid space nor Statistics penetrated an epidural vein, and an epidural catheter was Mean values of arterial PCO2 were compared using inserted gently. In ASA physical status IV patients, CEA ANOVA and paired Student's t test. was performed in the lateral decubitus position, using the loss of resistance technique. In both cases, patients were then placed in the supine or Trendelenberg position and Results the local anaesthetic solution was injected after a test dose The patient demographics are reported in Table I. Carotid of 2 ml of 2 per cent . The solution consisted of endarterectomy was performed in 326 patients and saphe- 15 ml, 0.5 per cent bupivacaine in the first 49 patients and nous vein bypass graft in 68. then of 15 ml, 0.37-0.40 per cent solution of the same local anaesthetic in the remainder. Fentanyl 50 to 100 Ixg was administered into the epidural space together with TABLE I Patients' demographics bupivacaine in 303 patients to improve analgesia. Arterial Sex ratio: 251 men; 143 women PCO2 was measured before and 30 min after epidural Mean age: 70.0 --- 8.4 yr anaesthesia in the first 50 patients who received Hypertension:* 268 (68%) bupivacaine-fentanyl solution. Sensory blockade was Documented ischemic cardiopathy:l" 169 (43%) evaluated by pin-prick. After cutaneous incision and Previous myocardial infarction: 5303.5%) Neurological symptoms: 286 (72.5%) dissection, the carotid sheath was opened after infiltration Transient ischaemic attacks: 156(39.5%) with lidocaine. When CAS included a vein bypass graft, Previous stroke: 41 00.5%) the saphenous vein was removed under local anaesthesia. Vertebral insufficiency 114 (29%)

Monitoring *Includes patients treated for hypertension or with a systolic blood pressure > 180 mmHg and/or a diastolic blood pressure > 100 mmHg. Routinely, monitoring included electrocardiogram ( l'Documented by typical chest pain, ECG and/or thallium scintigraphy CM5) and arterial blood pressure measured by a sphyg- or coronary . Bonnet etal.: EPIDURAL ANAESTHESIA FOR CAROTID SURGERY 355

Effectiveness of anaesthesia other patients, the decrease in blood pressure and heart Within 30 min of epidural injection, sensory blockade rate, if any, was less than 20 per cent of control values. extended from C2 to T4-Ts. One hundred eighty-five Minor side-effects as nasal congestion and hoarseness patients felt comfortable during the surgical procedure were observed in 10.5 per cent of the patients. and did not require additional analgesia. Two hundred and nine patients received small titrated doses of IV benzo- Neurological outcome and complications of surgery diazepines (diazepam: 2-10 mg, flunitrazepam:0.2-1 Transient alteration in consciousness and/or motor deficit mg) or narcotics (fentanyl: 25-50 p,g) but verbal com- of the right arm were noticed in 84 patients (21.3 per cent) munication was always maintained. No patient required during the surgical procedure. In two patients a transient additional epidural injections. decreased level of consciousness was observed during carotid dissection. In 35 patients, a sudden alteration in Unwarranted effects consciousness with a loss of verbal communication The identification of the epidural space was successful in occurred within two minutes of carotid artery clamping. 386 patients. Epidural venipuncture occured in six pa- An arterial shunt was inserted in those patients and tients (Table II); in five of these the puncture was allowed continued carotid artery clamping without neuro- identified definitively by blood aspiration, the catheter logical disturbances in 31 patients. In four patients some was re-inserted in the superior adjacent spinal interspace alteration in consciousness persisted after shunt insertion and heparin was proscribed for surgery. In one patient, and general anaesthesia with tracheal intubation and seizures were noticed after injection through the epidural controlled ventilation was instituted. In 42 patients, catheter demonstrating the epidural venipuncture; sei- alteration in consciousness occurred during carotid zures were controlled after thiopentone IV injection and clamping. In four of these, the increase in blood pressure surgery was performed under general anaesthesia. Post- induced by ephedrine improved the level of conscious- operatively the patient had no neurological deficit. Pene- ness, in the remaining patients neurological disturbances tration of the dura was noted in two instances and these disappeared after declamping. In addition, transient two patients were operated upon with general anaesthesia neurological deficits were noticed within two minutes of (Table II). carotid declamping in five patients. Three patients with chronic obstructive pulmonary The first 24 hr after surgery were complicated by disease (COPD) developed progressive respiratory em- hemiplegia in 12 (three per cent) due to carotid occlusion barrassment within 20 min of the epidural injection of 0.5 in seven patients and to cerebral oedema induced by per cent bupivacaine and they were managed with hyperperfusion syndrome in five. Hypotension might be controlled pulmonary ventilation after induction of gener- implicated in the occurrence of carotid occlusion in two al anaesthesia (Table I1). Arterial PCO2 increased from patients. The five patients who developed a hyperperfu- 37.3 --- 3.4 to 40.2 • 3.3 mmHg (P < 0.05) when it was sion syndrome had had previously a severe (> 90 per measured in patients who received the fentanyl- cent) carotid artery stenosis. In three patients (0.75 per bupivacaine combination. cent) a postoperative myocardial infarction was docu- Transient or recurrent hypotension, as defined above, mented on the second postoperative day. The mortality was noticed in 43 (10.9 per cent) (lowest systolic blood rate of this series was 2.3 per cent (nine patients). Death pressure 90 mmHg) and bradycardia <45 min -I in 11 was related to neurological deficit in six patients, to patients (2.8 per cent) (lowest value 40 b. min -~) (Table myocardial infarction in one patient, and to cervical I1). This was treated promptly with IV ephedrine. In the haematoma in two patients.

TABLE II Complications of cervical epidural anaesthesia

Incidence Management

Hypotension (SAP < 95 mmHg) 43 ephedrine Bradycardia (HR < 45 rain -~) I I atropine Venipuncture 6 heparin cancelled Seizure I general anaesthesia Dural puncture 2 general anaesthesia Respiratory failure 3 controlled ventilation

SAP: systolic arterial pressure. HR: heart rate. 356 CANADIAN JOURNAL OF ANAESTHESIA

Discussion block may also impair intercostal muscle function. In This series of documents that CEA provided adequate young healthy volunteers no change in resting ventilation anaesthesia for CAS. Nevertheless side effects were was noticed after 1.5 per cent lidocaine cervical epidural observed, the most common being hypotension and administration. ,3 In patients free of previous respiratory bradycardia which require careful monitoring. dysfunction a mild decrease in tidal volume, minute ventilation associated with a slight increase in PaCO2 Anaesthetic technique have been found. ~4 Epidural fentanyl combined with the The technique of CEA appears to be simple and successful local anaesthetic solution depressed ventilation 15 but the in the majority of the patients. The hanging-drop tech- measured increase in PaCO2 was not important in this nique, performed in the sitting position, allowed ready study. Indeed, the 21 per cent of patients who showed identification of the cervical epidural space. At the C6-C 7 transient neurological deficit during the surgical proce- or CT-TI level the epidural space measures 3-4 mm while dure is comparable to the 18-25 per cent range of patients it becomes narrower in higher segments. 7 Diffusion of the who have been reported to have had EEG ischaemic local anaesthetic solution in the cephalad direction within abnormalities during carotid clamping under general the skull is precluded by the adhesion of the meningeal anaesthesia. 16'17 Cervical epidural anaesthesia induced dura to the endosteal dura. Diffusion may occur along the respiratory muscle paralysis in the three patients with spinal roots and at the base of the skull. 8 This might COPD after they received 0.5 per cent bupivacaine explain why a large volume of local anaesthetic solution without fentanyl. They demonstrated progressive dys- was necessary to obtain an effective blockade, despite the pnoea which required controlled pulmonary ventilation. small size of the cervical epidural space compared with Inadvertent subdural injection is an alternative explana- the size of the lumbar epidural space. By contrast, the tion for this type of accident. 18 Since respiratory failure thickness of the dura mater which is 2.5 mm at the cervical has also been documented after unilateral phrenic nerve versus 0.5 mm at the lumbar level9 might account for the block I9 this risk is not eliminated when a cervical block is infrequency of dural puncture. It occurred only twice at performed in patients with compromised respiratory the beginning of the series. In a series of 790 consecutive function. 2~ These complications encouraged us to reduce cervical epidural nerve blocks, Waldman reported only the concentration and the volume of epidurally injected two unintentional dural punctures.I~ To our knowledge, bupivacaine and to postpone patients with severely direct spinal trauma has never been reported with this compromised respiratory function. technique, though the proximity of the spinal cord necessitates a cautious approach. Epidural venipuncture CARDIOVASCULAR EFFECTS occurred in six patients. Since the pressure is especially Cardiac sympathetic blockade is induced by CEA and negative in epidural in the sitting position, the consequently decreases in arterial blood pressure and venipuncture was documented in these patients only by heart rate are observed. 21'22 Incomplete impairment in aspiration through the Tuohy needle. A venipuncture baroreflex sensitivity has also been noticed. 2~-23 Cardiac prevents the administration of heparin during the surgical sympathetic blockade induced by epidural block has been procedure or to postponement of surgery if heparin shown to reduce myocardial ischaemia in dogs 24 and to administration is absolutely indicated. In addition, one decrease the incidence of myocardial ischaemia in pa- may be concerned by the risk of epidural haematoma tients submitted to . 25 It is suggested that when heparin is given before carotid clamping. We did patients with coronary artery disease who are commonly not observe such an event in this series. Two larger series scheduled for CAS may benefit from CEA. By contrast, of 3164 and 950 anticoagulated patients selected for too great a decrease in blood pressure may compromise vascular surgery under epidural or spinal anaesthesia, coronary and cerebral perfusion and have to be corrected. were reported to be free of such complication.l~'12 Rao In this study, we observed a 0.75 per cent incidence of and E1 Etr, II suggested that complications of anticoagu- postoperative myocardial infarction which was slightly lant treatment may be avoided by withdrawing the less than the 1.4-2.0 percent reported in recent series 26'27 epidural catheter in the postoperative period, only when and was considerably less than the 10-18.2 per cent heparin activity is minimal. incidence reported in high-risk patients operated upon under general anaesthesia. 28.29 Consequences of CEA Comparison with cervical block RESPIRATORY EFFECTS Although this was not a comparative study, several Since the phrenic nerve originates from C3 to Cs, nerve observations may be made with the knowledge of the conduction may be impaired by CEA. Extension of the advantages and drawbacks of cervical blocks. Previous Bonnet etal.: EPIDURAL ANAESTHESIA FOR CAROTID SURGERY 357 reported series of patients operated upon with cervical 12 Odoon JA, Sih IL. Epidural analgesia and block were not analysed in terms of failures, side-effects therapy. Experience with one thousand cases of continu- or complications of the technique. ~,2 Nevertheless, com- ous epidural. Anaesthesia 1983; 38: 254-9. plications such as seizures (0.9 per cent) or unexpected 13 Dohi S, Takeshima R, Naito H. Ventilatory and circulatory spinal injection (0.9 per cent) have been described. 3~ responses to carbon dioxide and high level sympathecto- Minor side-effects included hoarseness, shivering, per- my induced by epidural blockade in awake humans. Anesth spiration, partial brachial plexus block and stellate gangli- Analg 1986; 65: 9-14. on block. 3~ By contrast, there is a very low incidence of 14 Takasaki M, Takahashi T. Respiratory function during cardiovascular complications of CAS with cervical block cervical and thoracic extradural analgesia in patients and, compared with general anaesthesia, a decrease in the with normal lungs. BrJ Anesth 1980; 52: 1271-5. incidence of postoperative hypertension and a reduction 15 Negre !. Gueneron JP, Ecoffey C et al. Ventilatory in the duration of hospital stay have been reported. 31'32 response to carbon dioxide after intramuscular and epidural fentanyl. Anesth Analg 1987; 66: 707-10. Clinical recommendations 16 Green RM, Messick WJ, Ricotta JJ et al. Benefits, Cervical epidural anaesthesia seems to be suitable and shortcomings, and costs of EEG monitoring. Ann Surg effective to perform CAS and to allow sensitive and 1985; 201: 785-92. reliable information on cerebral function to be obtained. 17 Michenfelder JD, Sundt TM, Fode N, Sharbrough FW. Cervical epidural anaesthesia is a simple technique, easy Isoflurane when compared to enflurane and halothane to perform in all circumstances by trained anaesthetists. decreases the frequency of cerebral ischemia during carotid The incidence of complications is low but side effects endtarerectomy. Anesthesiology 1987; 67: 336-40. such as hypotension and bradycardia occur frequently and 18 Stevens RA, Stanton-Hicks MDA. Subdural injection of require appropriate management. This technique should : a complication of epidural anesthesia. be considered as an alternative to cervical block for CAS. Anesthesiology 1985; 63: 323. 19 Knoblanche GE. The incidence and etiology of phrenic References nerve blockade associated with supraclavicular brachial I Conolly JE. in the awake plexus block. Anesth Intensive Care 1979; 7: 346-50. patient. Am J Surg 1985; 150: 159-5. 20 Chauvin M, Lebrault C, Gauneau P, Goeau O, Duvaldes- 2 Peitzman All, Webster MW, Loubeau JM, Grundy BL, tin P. 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Cervical epidural anesthesia for carotid endar- reflexes, Valsalva maneuver, coughing, swallowing, and terectomy. Surg Gynecol Obstet 1962; 117: 366-7. nasal stimulation during acute cardiac sympathetomy by 7 Cousins M J, Bromage PR. Epidural neural blockade. In: epidural blockade in awake humans. Anesthesiology Cousins M J, Bridenbaugh PO (Eds.). Neural Blockade. 1985; 63,500-8. 2nd ed. Philadelphia. JB Lippincott Co. 1988. 266. 24 Klassen GA, Bramwell RS, Bromage PR et al. Effect of 8 Mehta M, Maher R. Injection into the extra arachnoid acute sympathectomy by epidural anesthesia on the subdural space. Anaesthesia 1977; 32: 760-3. canine coronary circulation. Anesthesiology 1980; 52; 9 Cheng PA. The anatomical and clinical aspects of epidural 8-15. anesthesia. Part I. Anesth Analg 1963; 42: 398-406. 25 Reiz S, Balfors E. Coronary hemodynamic effects of l0 Waldman SD. Complications of cervical epidural nerve general anesthesia and surgery. Reg Anesth 1982; blocks with steroids: a prospective study of 790 7 (suppl): $8-S18. consecutive blocks. Reg Anesth 1989; 14: 149-51. 26 Cucchiara RF, Sundt TM, Michenfelder JD. Myocardial 11 Rao TKL, EI-Etr AA. Anticoagulation following place- infarction in carotid endarterectomy patients anesthe- ment of epidural and subarachnoid catheters. Anesthesi- tized with halothane, enflurane, or isoflurane. Anesthesiol- ology 1981; 55: 618-20. ogy 1988; 69: 783-4. 358 CANADIAN JOURNAL OF ANAESTHESIA

27 Winslow CM, Solomon DH, Chassin MR et al. The appropriateness of carotid endarterectomy. N Engl J Med 1988; 318: 721-7. 28 Shaw DA, Venables GS, Cartlidge NEF et al. Carotid endarterectomy in patients with transient cerebral ischemia. J Neurol Sci 1984; 64: 45-53. 29 Ennix CL Jr, Lawrie GM, Morris GC Jr et al. Improved results of carotid endarterectomy in patients with symptomatic coronary disease: an analysis of 1,546 consecutive carotid operations. Stroke 1981; 10: 122-5. 30 Satyanarayana T, Maghul A, Ramathan S, Tunrdorf H. Cervical plexus block for carotid endarterectomy. Anesthesiology 1981 ; 55: A 170. 31 Prough DS, Scuderi P, Stullken E, David CH. Myocardial infarction following regional anaesthesia in patients undergoing carotid endarterectomy. Can Anaesth Soc J 1984; 31: 192-6. 32 Corson JD, Chang BB, Leopold PW et al. Perioperative hypertension in patients undergoing carotid endarterec- tomy: shorter duration under regional block anesthesia. Circulation 1986; 74: 11-4.