Superficial vs combined cervical plexus block for carotid endarterectomy: a prospective, randomized study

Hemodynamic Safety and Effect of Dexmedetomidine on Superficial Cervical Block Quality for Carotid Endarterectomy: A Prospective Study

OBJECTIVE

Dexmedetomidine as an adjuvant to local anesthetics (LAs) in regional anesthesia has demonstrated a positive effect on the quality of regional blocks, but there are no studies on usage in superficial cervical block (SCB) for carotid endarterectomy (CEA), in which the management of mean arterial pressure is essential. The authors designed a prospective, randomized, double-blinded study to investigate the effects of the addition of dexmedetomidine on the hemodynamic management and quality of SCB.

DESIGN

A prospective, randomized, double-blinded study.

SETTING

A single-center study at a university hospital center.

PARTICIPANTS

Ultrasound-guided SCB was performed on 60 patients classified as American Society of Anesthesiologists Grades II and III undergoing elective CEA surgery who were assigned into 2 groups randomly.

INTERVENTION(S)

Both groups received 2 mg/kg of 0.5% levobupivacaine with 2 mg/kg of 2% lidocaine. The intervention group additionally received 50 μg of dexmedetomidine.

MEASUREMENTS AND MAIN RESULTS

The onset and duration of sensory block and analgesia, hemodynamic parameters, and adverse effects were recorded. There were minimum effects on hemodynamic parameters and no differences in the incidence of adverse effects. The time to first analgesia was longer in the intervention group than in the control group (N = 30). There was no difference in the duration of the sensory block between groups. The log-rank test indicated a significant difference in the probability of the Numeric Pain Rating Scale <3.

CONCLUSION

The addition of 50 μg of dexmedetomidine to 0.5% levobupivacaine and 2% lidocaine for SCB did not influence the hemodynamics and frequency of adverse effects. The median sensory block duration time showed no statistical difference between the groups, but the quality of analgesia postoperatively was much improved in the study group.

Regional Anesthesia for Vascular Surgery and Pain Management

Patients undergoing vascular surgery tend to have significant systemic comorbidities. Vascular surgery itself is also associated with greater cardiac morbidity and overall mortality than other types of noncardiac surgery. Regional anesthesia is amenable as the primary anesthetic technique for vascular surgery or as an adjunct to general anesthesia. When used as the primary anesthetic, regional anesthesia techniques avoid complications associated with general anesthesia in this challenging patient population. In this article, the authors describe regional anesthetic techniques for carotid endarterectomy, arteriovenous fistula creation, lower extremity bypass surgery, and amputation.

Regional Anesthesia in Neuroanesthesia Practice

Regional anesthesia has been an undervalued entity in neuroanesthetic practice. However, in the past few years, owing to the development of more advanced techniques, drugs and the prolific use of ultrasound guidance, the unrecognised potential of these modalities have been highlighted. These techniques confer the advantages of reduced requirements for local anesthetics, improved hemodynamic stability in the intraoperative period, better pain score postoperatively and reduced analgesic requirements in the postoperative period. Reduced analgesic requirement translates into lesser side effects associated with analgesic use. Furthermore, the transition from the traditional blind landmark-based techniques to the ultrasound guidance has increased the reliability and the safety profile. In this review, we highlight the commonly practised blocks in the neuroanesthesiologist's armamentarium and describe their characteristics, along with their individual particularities.

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.

Ultrasound-guided superficial cervical plexus block under dexmedetomidine sedation versus general anesthesia for carotid endarterectomy: a retrospective pilot study

Background

Carotid endarterectomy (CEA) has been performed under regional and general anesthesia (GA). The general anesthesia versus local anesthesia for carotid surgery study compared the two techniques and concluded that there was no difference in perioperative outcomes. However, since this trial, new sedative agents have been introduced and devices that improve the delivery of regional anesthesia (RA) have been developed. The primary purpose of this pilot study was to compare intraoperative hemodynamic stability and postoperative outcomes between GA and ultrasound-guided superficial cervical plexus block (UGSCPB) under dexmedetomidine sedation for CEA.

Methods

Medical records from 43 adult patients who underwent CEA were retrospectively reviewed, including 16 in the GA group and 27 in the RA group. GA was induced with propofol and maintained with sevoflurane. The UGSCPB was performed with ropivacaine under dexmedetomidine sedation. We compared the intraoperative requirement for vasoactive drugs, postoperative complications, pain scores using the numerical rating scale, and the duration of hospital stay.

Results

There was no difference between groups in the use of intraoperative antihypertensive drugs. However, intraoperative inotropic and vasopressor agents were more frequently required in the GA group (p<0.0001). In the GA group, pain scores were significantly higher during the first 24 h after surgery (p<0.0001 between 0-6 h, p<0.004 between 6-12 h, and p<0.001 between 12-24 h). The duration of hospital stay was significantly more in the GA group (13.3±4.6 days in the GA group vs. 8.5±2.4 days in the RA group, p<0.001).

Conclusion

In this pilot study, intraoperative hemodynamic stability and postoperative outcomes were better in the RA compared to the GA group.

[Regional anesthesia for carotid surgery : An overview of anatomy, techniques and their clinical relevance]

BACKGROUND

Perioperative care for patients undergoing carotid endarterectomy (CEA) often presents a challenge to the anesthesia provider, as this patient group commonly suffers from a wide range of comorbidities. Although clinical trials could not demonstrate a significant benefit associated with regional anesthesia for outcomes such as insult, cardiac infarction or mortality, many authors concur that regional anesthetic techniques might be preferential in specific patient populations for this type of surgery.

OBJECTIVES

This article aims to present an overview of the currently used techniques for regional anesthesia in CEA, as well as discussing their influence on the perioperative outcome.

MATERIALS AND METHODS

After performing an extensive search of medical databases (Pubmed/Medline) the authors present a narrative analysis and interpretation of recent literature.

RESULTS

Currently there is a clear trend towards ultrasound guided regional anesthesia and away from classic landmark based techniques. The literature seems to support the notion that superior and intermediate cervical blocks are safer and less invasive than deep blocks.

CONCLUSIONS

With regional anesthetic techniques evolving to be more and more complex, the use of ultrasound is becoming increasingly indispensable in the operating theatre. For anesthesiologists with sufficient training and a profound knowledge of the respective anatomy, regional anesthesia seems to be a veritable alternative to general anesthesia for CEA.

Effect of Superficial Cervical Plexus Block on Baroreceptor Sensitivity in Patients Undergoing Carotid Endarterectomy

OBJECTIVES

Regional anesthesia for patients undergoing carotid endarterectomy is associated with improved intraoperative hemodynamic stability compared with general anesthesia. The authors hypothesized that the reported advantages might be related to attenuated ipsilateral baroreflex control of blood pressure, caused by chemical denervation of the carotid bulb baroreceptor nerve fibers.

DESIGN

A prospective cohort study.

SETTING

Single-center university hospital.

PARTICIPANTS

The study included 46 patients undergoing carotid endarterectomy using superficial cervical block.

INTERVENTIONS

A noninvasive computational periprocedural measurement of baroreceptor sensitivity was performed in all patients. Two groups were formed, depending on the patients' subjective response to surgical stimulation regarding the necessity of additional intraoperative local anesthesia (LA) administration on the carotid bulb. Group A (block alone) included 23 patients who required no additional anesthesia, and group B (block + LA) consisted of 23 patients who required additional anesthesia.

MEASUREMENTS AND MAIN RESULTS

Baroreceptor sensitivity showed no significant change after application of the block in both groups (group A: median [IQR], 5.19 [3.07-8.54] v 4.96 [3.1-9.07]; p = 0.20) (group B: median [IQR], 4.47 [3.36-8.09] v 4.53 [3.29-8.01]; p = 0.55). There was a significant decrease in baroreceptor sensitivity in group B after intraoperative LA administration (median [IQR], 4.53 [3.29-8.01] v 3.31 [2.26-7.31]; p = 0.04).

CONCLUSIONS

Standard superficial cervical plexus block did not impair local baroreceptor function, and, therefore, it was not related to improved cerebral perfusion in awake patients undergoing carotid endarterectomy. However, direct infiltration of the carotid bulb was associated with the expected attenuation of baroreflex sensitivity.

Regional anesthesia for vascular surgery

Patients presenting for vascular surgery present a challenge to anesthesiologists because of their severe systemic comorbidities. Regional anesthesia has been used as a primary anesthetic technique for many vascular procedures to avoid the cardiovascular and pulmonary perturbations associated with general anesthesia. In this article the use of regional anesthesia for carotid endarterectomy, open and endovascular abdominal aortic aneurysm repair, infrainguinal arterial bypass, lower extremity amputation, and arteriovenous fistula formation is described. A focus is placed on reviewing the literature comparing anesthetic techniques, with brief descriptions of the techniques themselves.

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.

Bilateral superficial cervical plexus block in combination with general anesthesia has a low efficacy in thyroid surgery: a meta-analysis of randomized controlled trials

BACKGROUND

A combination of bilateral superficial cervical plexus block (BSCPB) and general anesthesia is recommended for thyroid surgery. Proof of the efficacy of this combination remains weak. Furthermore, data on the safety of this regimen are lacking. Therefore, a meta-analysis of randomized controlled trials (RCT) to evaluate the efficacy and safety of BSCPB as an adjunct to general anesthesia in patients receiving thyroid surgery was performed.

METHODS

A meta-analysis of RCT was performed that included interventional groups evaluating the efficacy of BSCPB 6 and 24 hours after thyroid surgery.

RESULTS

Eight RCT, including a total of 799 patients (463 who underwent BSCPB and 336 controls), were analyzed. A meta-analysis demonstrated a reduction in pain scores 6 hours (Hedges' g: -0.46 [95% CI: -0.74 to -0.19]; p=0.001) and 24 hours postoperatively (Hedges' g: -0.49 [95% CI: -0.71 to -0.27]; p<0.001) in patients who had undergone BSCPB. The relative risk for postoperative nausea and vomiting (PONV) was 0.80 (95% CI: 0.58 to 1.09, p=0.159) in patients receiving BSCPB. Procedure-related adverse events were reported in three of the 476 patients who had undergone BSCPB (0.6%; 95% CI: 0.1% to 2.0%). These three patients had transient paresis of the brachial plexus, combined with a diaphragmatic paresis in one case, and all spontaneously resolved.

CONCLUSION

The combination of BSCPB and general anesthesia has a significant benefit in reducing pain 6 and 24 hours after thyroid surgery. However, the effect on pain reduction is too small to be of clinical relevance. Although it is a safe procedure, the existing evidence allows for no recommendation concerning the application of BSCPB in thyroid surgery. Further trials should evaluate a dose-response relationship and the incidence of PONV with this regimen.

[Anesthesia for carotid endarterectomy: a review]

Cardiovascular diseases are associated with high rates of morbidity and mortality. Carotid artery stenosis causes between 20% and 25% of ischemic strokes, especially when an embolism is the underlying cause. Carotid endarterectomy is the treatment of choice when stenosis exceeds 60%. It is important to have an understanding of how to manage perioperative factors that can decrease the risk of stroke, infarction, and death. In contrast to the findings of earlier meta-analyses, the recent GALA trial of general versus local anesthesia concluded that the rates of stroke, myocardial infarction, and mortality during or soon after surgery are similar for both types of anesthesia.

Randomized controlled trial of bilateral superficial cervical plexus block versus placebo in thyroid surgery

Background

Bilateral superficial cervical block during thyroid surgery can reduce postoperative pain but its value is unclear. This randomized clinical trial assessed the efficacy of such regional anaesthesia on postoperative pain after thyroid surgery performed under general anaesthesia.

Methods

Patients undergoing thyroid surgery were randomized to one of four groups in a double-blind fashion. Patients received a cervical block with placebo or bupivacaine at the start or end of surgery. Postoperative pain, analgesic use and length of hospital stay were assessed.

Results

There were 159 patients eligible for analysis. The bupivacaine group had significantly less pain than the placebo group (P = 0·016). The timing of bupivacaine administration did not significantly influence pain (preoperative versus postoperative, P = 0·723). There was no difference between groups in the amount of analgesic used. Length of hospital stay was the same in the bupivacaine and placebo groups (P = 0·925) and when bupivacaine was administered at the beginning or end of surgery (P = 0·087).

Conclusion

Bilateral superficial cervical block with bupivacaine combined with general anaesthesia significantly reduced postoperative pain after thyroid surgery. Registration number: NCT00472446 (http://www.clinicaltrials.gov).

Thyroid surgery under monitored anesthesia care (MAC)

BACKGROUND

Thyroid surgery is usually performed under general anesthesia, but thyroid surgery under monitored anesthesia care (MAC) has become re-introduced. We report our experiences of 40 cases of thyroid surgery under MAC.

METHODS

Forty patients were enrolled in this study. Bilateral superficial cervical plexus block (BSCPB) was performed by using 1% mepivacaine with 1 : 200,000 epinephrine. After BSCPB, patients were sedated with propofol and fentanyl. Postoperative pain, sore throat, hoarseness, and postoperative nausea and vomiting (PONV) were assessed.

RESULTS

Mean postoperative pain VAS were 1.3, 1.2, 1.0, 0.8 and postoperative sore throat VAS 1.4, 1.4, 1.1, 0.9 at PACU (post-anesthesia care unit) and postoperative 3, 6, 12 h, respectively. The incidence of hoarseness was 25, 5, 2.5%, and 0% and PONV were 0, 5, 10%, and 7.5% at PACU and postoperative 3, 6, 12 h, respectively.

CONCLUSIONS

Thyroid surgery under MAC may be a suitable alternative to general anesthesia.

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.

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.

Effects of clonidine and superficial cervical plexus block on hemodynamic stability after carotid endarterectomy

OBJECTIVES

To evaluate the effects of 2 interventions (intravenous clonidine and superficial cervical block) on hemodynamic stability after carotid endarterectomy and to identify variables associated with hemodynamic instability.

DESIGN

Prospective, observational study, sequential enrollment.

SETTING

University hospital.

PARTICIPANTS

Two hundred seventy-five patients undergoing elective carotid endarterectomy under general anesthesia.

INTERVENTIONS

Group NN (n = 50) received no intervention. In group CN (n = 85), 3 mug/kg of clonidine were administered intravenously 30 minutes before the end of the operation. Group CB (n = 140) additionally received a superficial cervical plexus block (SCB) with 20 mL of naropine 0.5% before the induction of anesthesia.

MEASUREMENTS AND MAIN RESULTS

Clonidine alone (odds ratio [OR], 2.33; 95% confidence interval [CI], 1.45-3.76) and clonidine combined with an SCB (OR, 4.99; 95% CI, 3.19-7.82) resulted in a significant increase in hemodynamic stability after CEA (p < 0.001) from 53.3% (NN) to 70.0% (CN) and 83.3% (CB), respectively. The need for rescue medication decreased from 40.0% to 17.6% and 13.6% (p < 0.001). Both interventions significantly reduced the need for postoperative opioid analgesics (p < 0.01). Logistic regression analysis showed preoperative systolic blood pressure values greater than 170 mmHg (OR, 3.23; 95% CI, 1.76-5.93), previous cardiac interventions (OR, 3.3; 95% CI, 1.54-7.11), and the need for rescue medication in the awakening period (OR, 5.8; 95% CI, 2.88-11.52) to be independent risk factors for postoperative hemodynamic instability (p < or = 0.002).

CONCLUSIONS

Intravenous clonidine and superficial cervical block significantly improve cardiovascular stability after carotid endarterectomy. Patients with pre-existing excessive hypertension and previous coronary interventions must be considered a high-risk group.

The Superficial Cervical Plexus Block for Postoperative Pain Therapy in Carotid Artery Surgery. A Prospective Randomised Controlled Trial

OBJECTIVES

Rapid and reliable neurological evaluation soon after carotid artery surgery is feasible with modern methods of general anesthesia, but postoperative pain therapy remains a challenge. Use of opioids can mask neurological deficits. We investigated whether superficial cervical plexus block reduced postoperative opioid consumption after carotid endarterectomy.

DESIGN

Prospective, randomised, double-blinded, placebo controlled trial.

METHODS

46 patients undergoing unilateral carotid endarterectomy under general anesthesia were randomized to either superficial cervical block with ropivacaine (n=23) or placebo (n=23). A patient controlled analgesia device (PCA) delivering morphine was provided for all patients. Subjective pain levels (visual analog scale, VAS) were recorded. The primary outcome was total morphine consumption on discharge from the recovery room. Secondary outcomes included arterial pCO2 (as an indicator of central nervous effects of morphine) and patient satisfaction.

RESULTS

No adverse effects of the superficial cervical plexus block were reported. Four patients in the placebo group were excluded because of other drug use post-operatively. Per protocol analysis compared 23 patients in ropivacaine group and 19 patients in the placebo group. The ropivacaine group had a significant reduction in morphine consumption (3.8+/-2.0 versus 12.9+/-4.0, p<0.001), lower maximal pain scores (2.6+/-2.0 versus 5.8+/-1.6, p<0.001), and paCO2 levels (39.0+/-2.6 versus 41.9+/-3.4, p=0.008) at discharge from the recovery room. Patient satisfaction (1=very good to 6=insufficient) was substantially higher in the ropivacaine group (1.7+/-0.7 versus 3.1+/-1.2, p<00.01).

CONCLUSION

The significant and clinically relevant lower morphine consumption and pain score, as well as the substantially higher patient satisfaction demonstrate that superficial cervical plexus block provides effective pain relief for patients undergoing carotid endarterectomy.

Does clonidine 50 μg improve cervical plexus block obtained with ropivacaine 150 mg for carotid endarterectomy? A randomized, double-blinded study

STUDY OBJECTIVE

To evaluate the effects of adding 50 microg clonidine to 150 mg ropivacaine for superficial cervical plexus block in patients undergoing elective carotid endarterectomy (TEA).

DESIGN

Randomized, double-blind study.

SETTING

Departments of Anesthesia and Vascular Surgery of a university hospital.

PATIENTS

40 ASA physical status II and III patients undergoing elective TEA during superficial cervical plexus block.

INTERVENTIONS

Superficial cervical plexus block was placed using 20 mL of 0.75% ropivacaine alone (Ropi group, n = 20) or with the addition of 50 microg clonidine (Ropi-Clonidine group, n = 20). If required, analgesic supplementation was given with local infiltration with 1% lidocaine and intravenous fentanyl (50-microg boluses). Nerve block profile, need for intraoperative analgesic supplementation, and time to first analgesic request were recorded.

MEASUREMENTS AND MAIN RESULTS

Median (range) onset time was 10 minutes (5-25 min) in the Ropi group and 5 minutes (5-20 min) in the Ropi-Clonidine group (P < 0.05). Intraoperative consumption of both 1% lidocaine and fentanyl was higher in patients of the Ropi group (15 mL [0-25 mL] and 250 microg [50-300 microg]) than in patients of the Ropi-Clonidine group (8 mL [0-20 mL] and 0 microg [0-150 microg]; P < 0.05 and P < 0.05, respectively). First postoperative analgesic request occurred after 17 hours (10-24 hrs) in the Ropi group and 20 hours (10-24 hrs) in the Ropi-Clonidine group (P > 0.05).

CONCLUSIONS

Adding 50 microg clonidine to 150 mg ropivacaine for superficial cervical plexus block shortened the onset time and improved the quality of surgical anesthesia in patients undergoing elective TEA.