Superficial and deep cervical plexus block for carotid artery surgery: a prospective study of 1000 blocks

Influence of Anatomic Conditions on Efficacy and Safety of Combined Intermediate Cervical Plexus Block and Perivascular Infiltration of Internal Carotid Artery in Carotid Endarterectomy: A Prospective Observational Trial

Ultrasound-guided intermediate cervical plexus blockade with perivascular infiltration of the carotid artery bifurcation perivacular block (PVB) is a reliable technique for regional anesthesia in carotid endarterectomy (CEA). We investigated the effect of the carotid bifurcation level (CBL) on PVB efficacy and safety in patients undergoing CEA. This prospective observational cohort study included 447 consecutive CEA patients who received PVB over a 6-y period. Vascular and neurologic puncture-related complications were recorded. The CBL was localized at the low level (C4 and C5 vertebra, low-level [LL] group) in 381 (85.2%) patients and at the high level (C2 and C3 vertebra, high-level [HL] group) in 66 (14.8%) patients. Local anesthetic supplementation by surgeons was necessary in 64 (14.3%) patients in the LL group and 38 (59.4%) patients in the HL group (p < 0.001) and was associated with a higher rate of central neurologic complications in the HL group (p = 0.031). Therefore, the efficacy of the PVB may be influenced by the CBL.

Anesthetic considerations in transcarotid artery revascularization

Transcarotid artery revascularization is a relatively new technology made available to vascular interventionalists within the last several years for patients with carotid artery stenosis. However, the intraoperative techniques and perioperative management of these patients continues to evolve as more experience is gained. Herein, we consider some important principles of anesthesia for patients undergoing this procedure.

Effects of regional anesthesia techniques on local anesthetic plasma levels and complications in carotid surgery: a randomized controlled pilot trial

BACKGROUND

The ultrasound guided intermediate cervical plexus block with perivascular infiltration of the internal carotid artery (PVB) is a new technique for regional anesthesia in carotid endarterectomy (CEA). We conducted a pilot study investigating the effects of deep cervical block (DCB), intermediate cervical block alone (ICB) and PVB on perioperative complications in patients undergoing elective CEA. We hypothesized, that the ropivacaine plasma concentration is higher in patients receiving DCB compared to PVB and ICB.

METHODS

In a randomized controlled pilot study thirty patients scheduled for elective CEA were randomly assigned into three groups: DCB receiving 20 mL ropivacaine 0.5% (n = 10), ICB receiving 20 mL ropivacaine 0.5% (n = 10) and PVB receiving 20 mL ropivacaine 0.5% and 10 mL ropivacaine 0,3% (n = 10). As primary outcome, plasma levels of ropivacaine were measured with high performance liquid chromatography before, 5, 10, 20, 60, and 180 min after the injection of ropivacaine. Secondary outcomes were vascular and neurological complications as well as patients' and surgeons' satisfaction. All analyses were performed on an intention-to-treat basis. Statistical significance was accepted at p < 0.05.

RESULTS

No conversion to general anesthesia was necessary and we observed no signs of local anesthetic intoxication or accidental vascular puncture. Plasma concentration of ropivacaine was significantly higher in the DCB group compared to PVB and ICB (p < 0.001) and in the PVB group compared to ICB (p = 0.008). Surgeons' satisfaction was higher in the PVB group compared to ICB (p = 0.003) and patients' satisfaction was higher in the PVB group compared to ICB (p = 0.010) and DCB group (p = 0.029). Phrenic nerve paralysis was observed frequently in the DCB group (p < 0.05). None of these patients with hemi-diaphragmatic paralysis showed signs of respiratory distress.

CONCLUSION

The ultrasound guided PVB is a safe and effective technique for CEA which is associated with lower plasma levels of local anesthetic than the standard DCB. Considering the low rate of complications in all types of regional anesthesia for CEA, larger randomized controlled trials are warranted to assess potential side effects among the blocks.

TRIAL REGISTRATION

The trial was registered at German Clinical Trials Register (DRKS) on 04/05/2019 (DRKS00016705, retrospectively registered).

Cervical plexus block

Cervical plexus blocks (CPBs) have been used in various head and neck surgeries to provide adequate anesthesia and/or analgesia; however, the block is performed in a narrow space in the region of the neck that contains many sensitive structures, multiple fascial layers, and complicated innervation. Since the intermediate CPB was introduced in addition to superficial and deep CPBs in 2004, there has been some confusion regarding the nomenclature and definition of CPBs, particularly the intermediate CPB. Additionally, as the role of ultrasound in the head and neck region has expanded, CPBs can be performed more safely and accurately under ultrasound guidance. In this review, the authors will describe the methods, including ultrasound-guided techniques, and clinical applications of conventional deep and superficial CPBs; in addition, the authors will discuss the controversial issues regarding intermediate CPBs, including nomenclature and associated potential adverse effects that may often be neglected, focusing on the anatomy of the cervical fascial layers and cervical plexus. Finally, the authors will attempt to refine the classification of CPB methods based on the target compartments, which can be easily identified under ultrasound guidance, with consideration of the effects of each method of CPB.

A Safe Regional Technique in a High-risk Patient: Cervical Plexus Blockage

Regional anesthesia in the form of combined cervical plexus block is gaining popularity as a technique of choice for cervical spine surgeries, especially for urgent ones. An important advantage is that it allows continuous monitoring of patient's neurological status. The success of the block often depends on accurate placement of the local anesthetic. Landmarks for the block are therefore of great importance. In this case, we aimed to present a 74-year-old man with C4–5 odontoid fracture. We planned to perform a unilateral combined cervical plexus block for anterior cervical instrumentation and fusion (ACIF) operation because of his associated high-risk comorbid disorders.

Pain Associated with Carotid Artery Surgery Performed under Carotid Plexus Block: Preemptive Analgesic Effect of Ketorolac

Carotid artery surgery (CAS) performed under cervical plexus block is frequently associated with significant intra- and postoperative pain. To evaluate whether preoperative administration of ketorolac may improve analgesia in this type of surgery, 80 patients scheduled for CAS under cervical plexus block were randomly allocated to receive intravenously either 30 mg of ketorolac or placebo 30 minutes before surgery. Verbal rating scale pain scores during surgery and 3 and 6 hours after surgery, the number of patients requiring additional analgesia, and the total analgesic consumption both during and within 6 hours after surgery were significantly lower, whereas the time to first postoperative analgesia was significantly shorter in the ketorolac group than in the control group.

The results of this prospective, randomized, double-blind study show that a single 30 mg dose of ketorolac administered intravenously 30 minutes before surgery reduces intraoperative pain and preempts postoperative pain in patients undergoing CAS under carotid plexus block.

Cervical epidural analgesia in current anaesthesia practice: systematic review of its clinical utility and rationale, and technical considerations

Cervical epidural analgesia (CEA) is an analgesic technique, potentially useful for surgeries involving the upper body. Despite the inherent technical risks and systemic changes, it has been used for various surgeries. There have been no previously published systematic reviews aimed at assessing its clinical utility. This systematic review was performed to explore the perioperative benefits of CEA. The review was also aimed at identifying the rationale of its use, reported surgical indications and the method of use. We performed a literature search involving PubMed and Embase databases, to identify studies using CEA for surgical indications. Out of 467 potentially relevant articles, 73 articles were selected. Two independent investigators extracted data involving 5 randomized controlled trials, 17 observational comparative trials, and 51 case reports (series). The outcomes studied in most comparative studies were on effects of local anaesthetics and other agents, systemic effects, and feasibility of CEA. In one randomized controlled study, CEA was observed to decrease the resting pain scores after pharyngo-laryngeal surgeries. In a retrospective study, CEA was shown to decrease the cancer recurrence after pharyngeal-hypopharyngeal surgeries. The limited evidence, small studies, and the chosen outcomes do not allow for any specific recommendations based on the relative benefit or harm of CEA. Considering the potential for significant harm, in the face of better alternatives, its use must have a strong rationale mostly supported by unique patient and surgical demands. Future studies must aim to assess analgesic comparator effectiveness for clinically relevant outcomes.

Regional anaesthesia for carotid endarterectomy

Summary Regional anaesthesia is a popular choice for patients undergoing carotid endarterectomy (CEA). Neurological function is easily assessed during carotid cross-clamping; haemodynamic control is predictable; and hospital stay is consistently shorter compared with general anaesthesia (GA). Despite these purported benefits, mortality and stroke rates associated with CEA remain around 5% for both regional anaesthesia and GA. Regional anaesthetic techniques for CEA have improved with improved methods of location of peripheral nerves including nerve stimulators and ultrasound together with a modification in the classification of cervical plexus blocks. There have also been improvements in local anaesthetic, sedative, and arterial pressure-controlling drugs in patients undergoing CEA, together with advances in the management of patients who develop neurological deficit after carotid cross-clamping. In the UK, published national guidelines now require the time between the patient's presenting neurological event and definitive treatment to 1 week or less. This has implications for the ability of vascular centres to provide specialized vascular anaesthetists familiar with regional anaesthetic techniques for CEA. Providing effective regional anaesthesia for CEA is an important component in the armamentarium of techniques for the vascular anaesthetist in 2014.

Regional anaesthesia techniques for carotid surgery: the state of art

PURPOSE

This review will analyse some aspects of regional anaesthesia (RA) for carotid endarterectomy (CEA), a surgical procedure which requires a strict monitoring of patient's status. RA remains an important tool for the anaesthesiologist. Some debates remain about type and definition of regional anaesthesia, efficacy and safety of the different cervical block techniques, the right dose, concentration and volume of local anaesthetic, the use of adjuvants, the new perspectives: ultrasonography, the future directions.

METHODS

A literature search was performed for journal articles in English language in the PubMed Embase and in The Cochrane Library database, from January 2000 to December 2013. The electronic search strategy contained the following medical subject headings and free text terms: local anaesthesia versus general anaesthesia for endarterectomy, superficial and deep cervical block, complications of cervical nerve block, ultrasound guidance of superficial and deep cervical plexus block.

CONCLUSIONS

The gold standard for RA will be achieved after overcoming a number of limitations by a more extensive use of ultrasonography, by combining general and regional anaesthesia, including conscious anaesthesia, by defining the appropriate volume, concentration and dosage of local agents and by addition of adjuvants.

Combination of high-resolution ultrasound-guided perivascular regional anesthesia of the internal carotid artery and intermediate cervical plexus block for carotid surgery

All previously documented regional anesthesia procedures for carotid artery surgery routinely require additional local infiltration or systemic supplementation with opioids to achieve satisfactory analgesia because of the complex innervation of the surgical site. Here, we report a reliable ultrasound-guided anesthesia method for carotid artery surgery. High-resolution ultrasound-guided regional anesthesia using a 12.5-MHz linear ultrasound transducer was performed in 34 patients undergoing carotid endarterectomy. Anesthesia consisted of perivascular regional anesthesia of the internal carotid artery and intermediate cervical plexus block. The internal carotid artery and the nerves of the superficial cervical plexus were identified, and a needle was placed dorsal to the internal carotid artery and directed cranially to the carotid bifurcation under ultrasound visualization. After careful aspiration, local anesthetic was spread around the internal carotid artery and the carotid bifurcation. In the second step, local anesthetic was injected below the sternocleidomastoid muscle along the previously identified nerves of the intermediate cervical plexus. The necessity for intra-operative supplementation and the conversion rate to general anesthesia were recorded. Ultrasonic visualization of the region of interest was possible in all cases. Needle direction was successful in all cases. Three to five milliliters of 0.5% ropivacaine produced satisfactory spread around the carotid bifurcation. For intermediate cervical plexus block, 10 to 20 mL of 0.5% ropivacaine produced sufficient intra-operative analgesia. Conversion to general anesthesia because of an incomplete block was not necessary. Five cases required additional local infiltration with 1% prilocaine (2-6 mL) by the surgeon. Visualization with high-resolution ultrasound yields safe and accurate performance of the block. Because of the low rate of intra-operative supplementation, we conclude that the described ultrasound-guided perivascular anesthesia technique is effective for carotid artery surgery.

Regional anesthesia for vascular surgery

Vascular surgical patients are a diverse group of patients who tend to be elderly, with multiple comorbidities, while vascular procedures may involve significant blood loss and ischemia of tissues beyond the arterial obstruction. Regional anesthesia techniques may offer benefits to patients undergoing vascular surgery because of their cardiorespiratory comorbidities. However, this group of patients is commonly receiving multiple medications, including anticoagulants, so regional techniques are not without risks. This review will discuss this topic based around 3 fundamental revascularization procedures, carotid, abdominal aortic aneurysm repair, and infrainguinal surgery, discussing the clinical applications of regional techniques relevant to each key area.

Ultrasound-guided combined intermediate and deep cervical plexus nerve block for regional anaesthesia in oral and maxillofacial surgery

OBJECTIVES

We examined the application of an ultrasound-guided combined intermediate and deep cervical plexus nerve block for regional anaesthesia in patients undergoing oral and maxillofacial surgery.

METHODS

A total of 19 patients receiving ultrasound-guided combined intermediate and deep cervical plexus anaesthesia followed by neck surgery were examined prospectively. The sternocleidomastoid and the levator of the scapula muscles as well as the cervical transverse processes were used as easily depicted ultrasound landmarks for the injection of local anaesthetics. Under ultrasound guidance, a needle was advanced in the fascial band between the sternocleidomastoid and the levator of the scapula muscles and 15 ml of ropivacaine 0.75% was injected. Afterwards, the needle was advanced between the levator of the scapula and the hyperechoic contour of the cervical transverse processes and a further 15 ml of ropivacaine 0.75% was injected. The sensory block of the cervical nerve plexus, the analgesic efficacy of the block within 24 h after injection and potential block-related complications were assessed.

RESULTS

All patients showed a complete cervical plexus nerve block. No patient required analgesics within the first 24 h after anaesthesia. Two cases of blood aspiration were recorded. No further cervical plexus block-related complications were observed.

CONCLUSIONS

Ultrasound-guided combined intermediate and deep cervical plexus block is a feasible, effective and safe method for oral and maxillofacial surgical procedures.

Ultrasound anatomy of the cervical paravertebral space: a preliminary study

PURPOSE

The aim of the study was to examine the ultrasound anatomy of the cervical paravertebral space in order to facilitate the implementation of sonographically guided regional anesthesia techniques for this region.

METHODS

Twenty volunteers were recruited, and the anatomic components of the cervical paravertebral space were sonographically examined. The transducer was positioned in the axial and coronal plane at the posterior cervical triangle. The cervical transverse processes with their respective nerve roots, the deep cervical fascia and the paravertebral muscles were identified.

RESULTS

There was excellent visualization of the C-3, C-4, C-5, C-6 and C-7 transverse processes in all cases. Excellent visualization of the scalene muscles, vertebral artery and deep cervical fascia was also achieved in all cases. Visualization of the levator of scapula muscle was difficult in 9 and excellent in 11 out of the 20 cases. In all cases, visualization of the C-1, C-2 and C-3 nerve roots was unfeasible. The identification of the C-4 nerve root was excellent in 3, difficult in 6 and unfeasible in 11 out of the 20 cases. The C-5, C-6 and C-7 nerve roots were excellently identified in all cases. The C-8 nerve root was identified only in 8 of the 20 cases. The cervical nerve roots also showed high variation, dividing into more than one branch as they exited the cervical transverse processes.

CONCLUSION

Cervical paravertebral anatomy can be depicted with ultrasound imaging techniques. This could be highly clinically significant for the implementation of regional anesthesia techniques.

Pharmacokinetics of levobupivacaine 0.5% after superficial or combined (deep and superficial) cervical plexus block in patients undergoing minimally invasive parathyroidectomy

STUDY OBJECTIVE

To evaluate the pharmacokinetic profile of 0.35 mL/kg of 0.5% levobupivacaine during superficial and combined (deep and superficial) cervical plexus block (CPB) in patients undergoing minimally invasive parathyroidectomy.

DESIGN

Prospective randomized study.

SETTING

Operating theater of a university hospital.

PATIENTS

12 ASA physical status II and III patients (11 women and 1 man), scheduled for minimally invasive parathyroidectomy.

INTERVENTIONS

Seven and 5 patients were randomly assigned to receive either superficial or combined CPB, respectively. The superficial CPB was performed with an injection of 0.35 mL/kg of 0.5% levobupivacaine subcutaneously along the posterior border of the sternocleidomastoid muscle and deeper on its medial surface. The combined CPB was initiated by the deep block at the C3 level vertebra by injecting 0.2 mL/kg of 0.5% levobupivacaine, followed by the superficial block with an injection of the remaining 0.15 mL/kg. After completion of the block, venous blood was sampled at the intervals of 5, 10, 15, 20, 30, 45, and 60 minutes.

MEASUREMENTS AND MAIN RESULTS

Venous plasma concentrations were measured using gas chromatography-mass spectroscopy. Mean +/- SD of maximal concentrations of levobupivacaine was 0.58 +/- 0.41 mg/L in group superficial and 0.52 +/- 0.28 mg/L in group combined (P = 0.71). The median (range) time required to reach the maximal concentrations was 30 minutes (20-30 min) in group superficial and 20 minutes (15-30 min) in group combined (P = 0.45). The areas under the drug concentration/time curve (AUC(10-60)) were also similar in both groups. No signs of central nervous system or cardiovascular toxicity or other untoward events were observed in any patient.

CONCLUSION

With the given dose regimen, levobupivacaine plasma concentrations were within safe ranges.

Comparison between general anesthesia and superficial cervical plexus block in partial thyroidectomies

Aim

Case report and Methods

Results

Conclusion

A prospective, randomized comparison between combined (deep and superficial) and superficial cervical plexus block with levobupivacaine for minimally invasive parathyroidectomy

BACKGROUND

Minimally invasive parathyroidectomy (MIP) can be performed under cervical plexus block (CPB). Superficial CPB has been reported to be easier to perform with similar efficacy and less anesthesia-related complications than combined deep and superficial CPB. In this study, we compared the efficacy of superficial and combined (deep and superficial) CPB in patients undergoing MIP.

METHODS

Forty-two patients with primary hyperparathyroidism due to a solitary adenoma were randomized to receive either a superficial (group superficial, n = 20) or a combined deep and superficial CPB (group combined, n = 22) using 0.35 mL/kg of 0.5% levobupivacaine. The primary end-point was the amount of supplemental fentanyl required to complete surgery.

RESULTS

There were no differences in onset of block, pain scores during surgery, or time to first analgesic request between groups. Fentanyl consumption was similar in both groups, i.e., 50 (0-200) microg in group superficial and 50 (0-100) microg in group combined (P = 0.60). Six patients [1 in group superficial (5%) and 5 in group combined (22.7%)] were converted to general anesthesia for surgically required bilateral neck dissection (P = 0.18). General anesthesia for block failure was reported in three superficial (15%) and two combined group patients (9%) (P = 0.99). In group combined, only one patient (4.5%) showed diaphragmatic paresis after the block (P = 0.99).

CONCLUSION

Superficial CPB is an alternative to combined block for MIP.

Regional anaesthesia for carotid endarterectomy: an audit over 10 years

BACKGROUND

The aim of this retrospective study was to compare the failure rates and the frequency of anaesthesia-related complications of two different methods of regional anaesthesia used for carotid endarterectomy--cervical epidural (CE) anaesthesia and cervical plexus block (CPB).

METHODS

The study included 1828 carotid endarterectomies performed in 1455 patients between 1996 and 2006. A combination of deep and superficial CPB was used for 1166 procedures, whereas in 662 cases surgery was performed under CE anaesthesia.

RESULTS

The failure rate of CPB was 3% compared with 6.9% for CE anaesthesia (P < 0.0001). The reasons for failure of the anaesthetic techniques were (1) technical failure, (2) insufficient analgesia, (3) non-compliant patients, and (4) anaesthetic complications. The incidence of complications resulting from CE anaesthesia was significantly higher than with CPB; life-threatening complications--2% compared with 0.3% (P < 0.0001); other anaesthesia-related complications 5.7 vs 4.7%. Serious complications included inadvertant injection into the subarachnoid space or vertebral artery. The frequency of shunt insertion, perioperative stroke, and death from any cause was similar in both groups of patients.

CONCLUSIONS

Both methods of regional anaesthesia are acceptable for carotid artery surgery. CPB is associated with a significantly lower frequency of anaesthesia-related complications and should therefore be considered the anaesthetic of choice. CE anaesthesia should not be performed except in extenuating circumstances such as variant anatomy or the requirement for more extensive surgery.

Superficial or deep cervical plexus block for carotid endarterectomy: a systematic review of complications †

Carotid endarterectomy is commonly conducted under regional (deep, superficial, intermediate, or combined) cervical plexus block, but it is not known if complication rates differ. We conducted a systematic review of published papers to assess the complication rate associated with superficial (or intermediate) and deep (or combined deep plus superficial/intermediate). The null hypothesis was that complication rates were equal. Complications of interest were: (1) serious complications related to the placement of block, (2) incidence of conversion to general anaesthesia, and (3) serious systemic complications of the surgical-anaesthetic process. We retrieved 69 papers describing a total of 7558 deep/combined blocks and 2533 superficial/intermediate blocks. Deep/combined block was associated with a higher serious complication rate related to the injecting needle when compared with the superficial/intermediate block (odds ratio 2.13, P = 0.006). The conversion rate to general anaesthesia was also higher with deep/combined block (odds ratio 5.15, P < 0.0001), but there was an equivalent incidence of other systemic serious complications (odds ratio 1.13, P = 0.273; NS). We conclude that superficial/intermediate block is safer than any method that employs a deep injection. The higher rate of conversion to general anaesthesia with the deep/combined block may have been influenced by the higher incidence of direct complications, but may also suggest that the superficial/combined block provides better analgesia during surgery.

Frequency of transient ipsilateral vocal cord paralysis in patients undergoing carotid endarterectomy under local anesthesia

BACKGROUND

Especially because of improvements in clinical neurologic monitoring, carotid endarterectomy done under local anesthesia has become the technique of choice in several centers. Temporary ipsilateral vocal nerve palsies due to local anesthetics have been described, however. Such complications are most important in situations where there is a pre-existing contralateral paralysis. We therefore examined the effect of local anesthesia on vocal cord function to better understand its possible consequences.

METHODS

This prospective study included 28 patients undergoing carotid endarterectomy under local anesthesia. Vocal cord function was evaluated before, during, and after surgery (postoperative day 1) using flexible laryngoscopy. Anesthesia was performed by injecting 20 to 40 mL of a mixture of long-acting (ropivacaine) and short-acting (prilocaine) anesthetic.

RESULTS

All patients had normal vocal cord function preoperatively. Twelve patients (43%) were found to have intraoperative ipsilateral vocal cord paralysis. It resolved in all cases < or =24 hours. There were no significant differences in operating time or volume or frequency of anesthetic administration in patients with temporary vocal cord paralysis compared with those without.

CONCLUSION

Local anesthesia led to temporary ipsilateral vocal cord paralysis in almost half of these patients. Because pre-existing paralysis is of a relevant frequency (up to 3%), a preoperative evaluation of vocal cord function before carotid endarterectomy under local anesthesia is recommended to avoid intraoperative bilateral paralysis. In patients with preoperative contralateral vocal cord paralysis, surgery under general anesthesia should be considered.

A comparison of dexmedetomidine versus conventional therapy for sedation and hemodynamic control during carotid endarterectomy performed under regional anesthesia

The properties of dexmedetomidine (DEX) that result in titratable sedation and sympathetic modulation suggest that it would be suitable for use during carotid endarterectomy (CEA) performed under regional anesthesia. We performed a randomized, double-blind study in 56 patients having CEA under regional anesthesia and compared hemodynamic control using DEX versus a conventional sedation technique using midazolam and fentanyl standard (STD). Sedation was titrated to a Ramsay Sedation Score of 2-4 in both groups. The primary outcome was the number of pharmacological interventions required to treat deviations of arterial blood pressure and heart rate outside of predetermined limits. We also compared recovery hemodynamic profiles, patient satisfaction, and adverse cardiac and neurological events. There was no difference in the overall rate of hemodynamic interventions (DEX 80% versus STD 79%; P = 1.0). However, the nature of interventions differed in that patients in the DEX group were less likely to require treatment for hypertension and/or tachycardia (DEX 40% versus STD 72%; P = 0.03). The number of interventions per patient for hypertension and/or tachycardia was also lesser in the DEX group (P = 0.02). There were no significant differences in the numbers of patients needing intraoperative treatment for hypotension or bradycardia or in the need for intraarterial shunting. In the postanesthesia care unit, more patients in the DEX group required hemodynamic drug interventions (DEX 11, 44%, versus STD 4, 14%; P = 0.03). These were primarily for hypotension (DEX 7, 28% versus STD 3, 11%; P = 0.16). The number of patients requiring no additional pain relief in the postanesthesia care unit was significantly larger for patients in the DEX group (DEX 18, 72% versus STD 11, 38%; P = 0.027). DEX provides an acceptable alternative, without superiority to standard techniques for sedation during awake CEA.

Bilateral Vocal Cord Palsy During Carotid Endarterectomy Under Cervical Plexus Block

We describe a case of vocal cord palsy leading to respiratory obstruction during carotid endarterectomy under cervical plexus block in a patient who had preexisting contralateral vocal cord paralysis subsequent to a previous thyroidectomy. The patient required immediate tracheal intubation and subsequent tracheostomy to maintain the airway postoperatively. Care must be given to avoid contralateral vocal cord paralysis in the presence of a preexisting vocal cord palsy.

Regional anaesthesia and propofol sedation for carotid endarterectomy

BACKGROUND

Many surgeons now perform carotid endarterectomy under regional anaesthesia. The aim of the present study was to review a sedation technique using a computer-controlled infusion of propofol.

METHODS

A consecutive series of 84 carotid endarterectomies done by a single surgeon and commenced under regional anaesthesia with sedation was studied. There were 54 men and 27 women (three bilateral procedures), with a median age of 71 years (range 48-87 years). All patients had carotid stenosis > 70% 80 procedures were done for symptomatic disease and three asymptomatic patients were treated before cardiac surgery (one bilateral).

RESULTS

Seventy-seven procedures were completed under regional anaesthesia and sedation alone; seven required conversion to general anaesthetic, usually for intolerance of the operation. An intraoperative shunt was required on only four occasions (5%). Postoperatively eight patients required critical care monitoring, usually for blood pressure control. The remainder were nursed on the vascular ward, and 68% were discharged home on the day after surgery. No patient died, but there were two neurological complications. One patient had a cerebellar stroke 10 days after surgery, but recovered fully after 4 months. A second developed cerebral oedema due to severe intraoperative hypertension and required intensive care for 15 days. He too recovered fully. Five patients had a further episode of transient cerebral ischaemia within 1 month of operation, but in all cases duplex imaging showed a widely patent carotid and there were no sequelae.

CONCLUSION

Target controlled propofol infusion is an effective method of sedation in patients undergoing carotid endarterectomy.

Acute respiratory failure after deep cervical plexus block for carotid endarterectomy as a result of bilateral recurrent laryngeal nerve paralysis

We report about a case of acute respiratory distress (73-year-old female), which occurred minutes after a deep cervical plexus block (40 ml ropivacaine 0.5%) for carotid endarterectomy (CEA) and required immediate endotracheal intubation of the patient's trachea and consecutive mechanical ventilation. Subsequently, CEA was performed under general anaesthesia (TIVA) with continuous monitoring by somatosensory-evoked potentials. After a period of 14 hours, the endotracheal tube could be removed, the patient being in fair respiratory, cardiocirculatory and neurological conditions. Retrospectively, acute respiratory distress was caused by a combination of ipsilateral plexus blockade-induced and pre-existing asymptomatic contralateral recurrent laryngeal nerve (RLN) paralysis confirmed by a postoperative ENT-check and related to previous thyroid surgery more than 50 years ago. RLN paralysis, often being asymptomatic, represents a typical complication of thyroid and other neck surgery with reported incidences of 0.5-3%. Therefore, a thorough preoperative airway check is advisable in all patients scheduled for a cervical plexus block. Particularly in cases with a history of respiratory disorders or previous neck surgery a vocal cord examination is recommended, and the use of a superficial cervical plexus block may lower the risk of respiratory complications. This may prevent a possibly life-threatening coincidence of ipsilateral plexus blockade-induced and pre-existing asymptomatic contralateral RLN paralysis.

Dexmedetomidine for awake carotid endarterectomy: efficacy, hemodynamic profile, and side effects

: A randomized, double-masked, placebo-controlled study was designed to compare dexmedetomidine as a primary sedative agent with a commonly used drug combination in patients undergoing awake carotid endarterectomy (CEA). Sixty-six patients undergoing CEA (ASA II-IV) were randomly assigned to receive either dexmedetomidine (total dose of 97.5 +/- 54.7 mcg) or normal saline (control). Supplemental doses of midazolam, fentanyl, and/or propofol were administered as deemed necessary by the anesthesiologist. An observer blinded to the study drug assessed sedation level (Observer's Assessment of Alertness-Sedation [OAA/S] scale). The primary outcomes were defined as the number of patients with an OAA/S score of 4 intraoperatively and an OAA/S score of 5 postoperatively. The authors also compared cardiorespiratory parameters, intra- and postoperative side effects, and complications. Chi-square tests were used to analyze the primary endpoints. All secondary parameters were analyzed using the Wilcoxon rank sum test. Three patients in the dexmedetomidine group (10%) had an OAA/S score of 4 at all four time points assessed intraoperatively, while no patient in the control group had a score of 4 at all the time points considered. Thirteen patients in the dexmedetomidine group had a score of 4 at three or more time points (42%) compared with six patients (19%) in the control group. Four patients in the control group (13%) and one patient in the dexmedetomidine group (3%) did not achieve a score of 4 at any of the four critical intraoperative time points (chi for association = 9.9, P < 0.05; chi for a trend = 8.6, P < 0.004, with the trend favoring dexmedetomidine). More patients in the control group required treatment with metoprolol (26% vs. 6%, P = 0.04) and labetalol (48% vs/ 6%, P < 0.01). Plasma levels of norepinephrine were significantly lower in the dexmedetomidine group during and after surgery compared with the control group. Six patients (19%) in the dexmedetomidine group required intra-arterial shunts, while only two patients (6%) required shunts in the control group (P = 0.16). These data show that the use of dexmedetomidine in patients undergoing awake CEA resulted in fewer fluctuations from the desired sedation level. Patients receiving dexmedetomidine required less antihypertensive therapy compared with the midazolam/fentanyl/propofol combination. The effect of dexmedetomidine on cerebrovascular circulation in the study population needs further investigation.

Remifentanil or propofol for sedation during carotid endarterectomy under cervical plexus block

BACKGROUND

During carotid endarterectomy under regional anaesthesia, patients often require medication to control haemodynamic instability and to provide sedation and analgesia. Propofol and remifentanil are used for this purpose. However, the benefits, side-effects, and optimal dose of these drugs in such patients are unclear.

METHODS

Sixty patients were included in a prospective, randomized, single blinded study. All patients received a deep cervical plexus block with 30 ml ropivacaine 0.75% and were randomized to receive either remifentanil 3 micro g kg(-1) h(-1) or propofol 1 mg kg(-1) h(-1). The infusions were started after performing the regional block and were stopped at the end of surgery. Arterial pressure, ECG, ventilatory rate, and Pa(CO(2)) were measured continuously and recorded at predetermined times. Twenty-four hours after surgery, patient comfort, and satisfaction were also evaluated.

RESULTS

In three patients, the infusion of remifentanil had to be stopped because of severe respiratory depression or bradycardia. No significant differences were found between the two groups in haemodynamic variables or sedative effects, but there was a significantly greater decrease in ventilatory frequency and increase in Pa(CO(2)) in the remifentanil group. The patient's subjective impressions and pain control were excellent in both groups.

CONCLUSION

As a result of the higher incidence of adverse respiratory effects with remifentanil and similar sedative effects, propofol is preferable for sedation during cervical plexus block in elderly patients with comorbid disease at the dosage used.

Insertion of vagal nerve stimulator using local and regional anesthesia

BACKGROUND

Vagal nerve stimulation (VNS) is a valuable therapy for patients with intractable epilepsy. Placement of a vagal nerve stimulator typically requires general anesthesia, which frequently interrupts anticonvulsant therapy. Insertion of the stimulator using regional/local anesthesia may offer the advantages of continuity of anticonvulsant therapy and implantation in the outpatient setting.

METHODS

We retrospectively compared the first 10 consecutive patients undergoing VNS implantation under general anesthesia with the first 12 consecutive patients undergoing VNS implantation under regional/local anesthesia. Patients for the regional/local anesthesia were selected on the basis of their ability to cooperate and follow commands. Regional anesthesia for implantation of the VNS leads was achieved by performing superficial and deep cervical plexus blocks. A local anesthetic field block of a small area of the posterior chest provided anesthesia for insertion of the generator.

RESULTS

All of the patients undergoing regional/local anesthesia completed the procedure without difficulty and on an outpatient basis. None complained of discomfort, sedation, nausea, or vomiting and none had seizures in the perioperative period. These results contrasted with the group that underwent general anesthesia (n = 10), who had an 80% incidence of nausea and vomiting and a 30% incidence of postoperative seizures.

CONCLUSION

VNS implantation under regional/local anesthesia is proficiently performed as an outpatient procedure with minimal postoperative side effects.

Remifentanil conscious sedation during regional anaesthesia for carotid endarterectomy: rationale and safety

OBJECTIVES

to prospectively evaluate the safety and efficacy of remifentanil during regional anaesthesia for carotid endarterectomy.

METHODS

twenty-eight consecutive patients underwent carotid endarterectomy with combined superficial and deep cervical plexus block supplemented with continuous intravenous 0.04 microg.kg(-1).min(-1)remifentanil infusion. Depth of sedation was monitored using the Observer's Assessment of Alertness/Sedation Scale (OAA/S). The degree of pain, discomfort and anxiety was self-assessed by the patients using a horizontal visual analogue scale.

RESULTS

all patients experienced adequate comfort and analgesia. No local anaesthetic supplementation was necessary. No patient had a OAA/S score lower than 4 (with 5=awake/alert to 1=asleep). Respiratory depression did not occur. Selective shunting was required in four cases. No patient was converted to general anaesthesia. There were no permanent neurological deficits, cardiopulmonary complications or deaths.

CONCLUSION

remifentanil as a supplement to regional anaesthesia for carotid endarterectomy, provides comfort and analgesia without hampering mental status evaluation.

Blood pressure manipulation during awake carotid surgery to reverse neurological deficit after carotid cross-clamping

We describe the management of three patients undergoing awake carotid surgery who developed signs of cerebral ischaemia after carotid cross-clamping. Drug treatment to increase arterial blood pressure above baseline reversed the neurological deficit and an internal carotid artery shunt was not needed. Shunt insertion is less frequent with regional rather than general anaesthesia, and blood pressure control can reduce this even more. Coincidentally, one of the patients, who gave a history of angina of effort after walking 100 m, complained of chest pain after cross-clamp release. This was treated successfully with sublingual nitroglycerin before ST segment changes became apparent on the ECG. These reports suggest that regional anaesthesia for carotid surgery allows potential complications to be identified earlier than under general anaesthesia using reports from the patient, so that treatment may be modified to prevent morbidity and even mortality.

A comparison of superficial versus combined (superficial and deep) cervical plexus block for carotid endarterectomy: a prospective, randomized study

Carotid endarterectomy may be performed by using cervical plexus blockade with local anesthetic supplementation by the surgeon during surgery. Most practitioners use either a superficial cervical plexus block or a combined (superficial and deep) block, but it is unclear which offers the best operative conditions or greatest patient satisfaction. We compared the two techniques in patients undergoing carotid endarterectomy. Forty patients undergoing carotid endarterectomy were randomized to receive either a superficial or a combined cervical plexus block. Bupivacaine 0.375% to a total dose of 1.4 mg/kg was used. The main outcome measure was the amount of supplemental lidocaine 1% used by the surgeon. Subsidiary outcome measures were postoperative pain score, sedative and analgesic requirements before and during surgery, and postoperative analgesic requirements. Median supplemental lidocaine requirements were 100 mg (range 30-180 mg) in the superficial block group and 115 mg (range 30-250 mg) in the combined block group. These differences were not statistically significant (Mann-Whitney U-test). There was no significant difference in the number of patients needing postoperative analgesia between the groups (11 of 20 in the deep block group versus 8 of 20 in the superficial block group) in the 24 h after surgery. The median time to first analgesia in the superficial block group was 150 min, more than in the combined block group (median time 45 min) but this difference, although large, was not statistically significant (Mann-Whitney U-test). We found no significant differences between the anesthetic techniques studied. All patients reported satisfaction with the techniques.

Recurrent laryngeal nerve blockade in patients undergoing carotid endarterectomy under cervical plexus block

We report two cases of recurrent laryngeal nerve blockade arising during carotid endarterectomy under cervical plexus anaesthesia. These nerve blocks were thought to be due to the instillation of local anaesthetic. The nerve block in one patient was responsible for a paroxysm of coughing which caused the formation of a large neck haematoma. We believe this to be the first report of local anaesthetic induced recurrent laryngeal nerve blockade leading to such a complication.