Color Doppler ultrasonography of an agitated solution is predictive of accurate catheter placement for a continuous popliteal sciatic nerve block.

BACKGROUND: Continuous peripheral nerve catheters (PNCs) have been shown to provide superior postoperative analgesia, decrease opioid consumption, and improve patient satisfaction compared with single injection techniques. In order to achieve success and reliability, accurate catheter positioning is an essential element of PNC placement. An agitated solution of normal saline, D5W, or a local anesthetic solution can be produced by the introduction of air to the injectate, creating air bubbles that can enhance ultrasonographic visualization and possibly improve block success. METHODS: Eighty-three patients were enrolled. Ultrasound-guided continuous popliteal sciatic nerve blocks were performed by positioning the tip of a Tuohy needle between the tibial and common peroneal branches of the sciatic nerve and threading a catheter. An agitated local anesthetic solution was injected through the catheter, viewed with color Doppler ultrasound and video recorded. A peripheral block score (lower score = greater blockade, range 0-14) was calculated based upon the motor and sensory testing at 10, 20, and 30 min after block completion. The color Doppler agitation coverage pattern for the branches of the sciatic nerve was graded as follows: complete (> 50%), partial (> 0%, ≤ 50%), or none (0%). RESULTS: The degree of nerve blockade at 30 min as judged by median (10th, 90th percentile) peripheral block score was significant for partial or complete color Doppler coverage of the sciatic nerve injectate compared to no coverage [3 (0, 7) vs 8 (4, 14); p < 0.01] and block onset was faster (p = 0.03). The block success was higher in groups with partial or complete coverage of the branches of the sciatic nerve vs no coverage (96% vs 70%; p = 0.02). CONCLUSIONS: Injection of an agitated solution through a popliteal sciatic perineural catheter is predictive of accurate catheter placement when partial or complete coverage of the sciatic nerve branches is visualized with color Doppler ultrasound. TRIAL REGISTRATION: NCT01591603.

Comprehensive Analysis of 13,897 Consecutive Regional Anesthetics at an Ambulatory Surgery Center.

Objective: The authors investigated a wide range of perioperative outcome measures in the context of a robust regional anesthesia practice. Design: Comprehensive review of a prospectively collected six-year database. Setting: Freestanding, academic ambulatory surgery center. Subjects: There were 13,897 consecutive regional anesthetics in 10,338 patients. Methods: We investigated patient satisfaction, postoperative nausea and vomiting (PONV), postoperative pain, catheter analgesia, and complications. Clinical risk factors were examined and presented as odds ratios for multiple outcome analyses including block success, patient satisfaction, PONV, and postoperative neurologic symptoms (PONS). Results: Decreased block success was associated with nerve stimulation alone (P < 0.001), obesity (P = 0.001), higher American Society of Anesthesiologists classification (ASA; P = 0.01), lower extremity blocks (P = 0.04), and male sex (P < 0.001). Decreased patient satisfaction was associated with poor catheter analgesia (P < 0.001), complications (P < 0.001), higher ASA (P = 0.001), and younger age (P = 0.008). PONV was associated with postoperative pain (P < 0.005), female sex (P < 0.001), general anesthesia (P < 0.001), younger age (P = 0.001), lack of catheter (P = 0.03), and lack of dexamethasone/clonidine (D + C) adjuncts (P = 0.01). Serious complications and unexpected hospitalizations were rare (<0.2%). D + C adjuncts, lower extremity blocks, clonidine (but not dexamethasone alone), and female sex were associated with PONS (all P < 0.001). Conclusions: A regional anesthesia-based practice in ambulatory surgery is an effective means of providing excellent postoperative analgesia and is associated with a low rate of PONV and unexpected admissions. Dexamethasone, clonidine, and their combination when combined with 0.5% ropivacaine may have mixed effects on PONS risk that warrant dose/concentration alterations of these three drugs in the context of off-label perineural adjunct use.

Duration of upper and lower extremity peripheral nerve blockade is prolonged with dexamethasone when added to ropivacaine: a retrospective database analysis.

BACKGROUND: Dexamethasone, when added to local anesthetics, has been shown to prolong the duration of peripheral nerve blocks; however, there are limited studies utilizing large numbers of patients. The purpose of this study was to examine the effect of adding dexamethasone to ropivacaine on duration of nerve blocks of the upper and lower extremity. METHODS: We reviewed 1,040 patient records collected in an orthopedic outpatient surgery center that had received an upper or lower extremity peripheral nerve block with ropivacaine 0.5% with or without dexamethasone and/or epinephrine. The primary outcome was duration of analgesia in upper or lower extremity blocks containing dexamethasone as an adjunct. Secondary outcomes included postoperative patient pain scores, satisfaction, and the incidence of block related complications. Linear and ordinal logistic regression models were used to examine the independent effect of dexamethasone on outcomes. RESULTS: Dexamethasone was observed to increase median block duration by 37% (95% confidence interval: 31-43%). The increased block duration persisted within body regions (upper and lower) and across a range of block types. Dexamethasone was also observed to reduce pain scores on the day of surgery (P = 0.001) and postoperative day 1 (P < 0.001). There was no significant difference in duration of nerve blocks when epinephrine (1:400,000) was added to 0.5% ropivacaine with or without dexamethasone. CONCLUSION: The addition of dexamethasone to 0.5% ropivacaine prolongs the duration of peripheral nerve blocks of both the upper and lower extremity.

Regional blockade of the shoulder: approaches and outcomes.

The article reviews the current literature regarding shoulder anesthesia and analgesia. Techniques and outcomes are presented that summarize our present understanding of regional anesthesia for the shoulder. Shoulder procedures producing mild to moderate pain may be managed with a single-injection interscalene block. However, studies support that moderate to severe pain, lasting for several days is best managed with a continuous interscalene block. This may cause increased extremity numbness, but will provide greater analgesia, reduce supplemental opioid consumption, improve sleep quality and patient satisfaction. In comparison to the nerve stimulation technique, ultrasound can reduce the volume of local anesthetic needed to produce an effective interscalene block. However, it has not been shown that ultrasound offers a definitive benefit in preventing major complications. The evidence indicates that the suprascapular and/or axillary nerve blocks are not as effective as an interscalene block. However in patients who are not candidates for the interscalene block, these blocks may provide a useful alternative for short-term pain relief. There is substantial evidence showing that subacromial and intra-articular injections provide little clinical benefit for postoperative analgesia. Given that these injections may be associated with irreversible chondrotoxicity, the injections are not presently recommended.

Regional anesthesia procedures for shoulder and upper arm surgery upper extremity update--2005 to present.

This review of the literature since 2005 assesses developments of RA techniques commonly used for shoulder surgery, and their effectiveness for postoperative analgesia. Advantages of regional techniques include site-specific anesthesia and decreased postoperative opioid use. For shoulder surgeries, the ISB provides effective analgesia with minimal complications, whereas the impacts of IA single-injections remain unclear. When combined with GA, ISB can be used in lower volumes and reducing the complications for shoulder and proximal upper extremity. USG ISB and SCB are both effective and safe for shoulder surgery with a low incidence of complications, especially PONS.53 When compared with intravenous patient-controlled opioid analgesia, a perineural LA infusion using a disposable pump with patient-controlled LA bolus function has led to better pain relief and functional recovery while decreasing the need for rescue analgesics and the number of adverse events after ambulatory orthopedic surgery. The most remarkable advance in RA in the past 5 years is the increased usage of USG. Although there are no large-scale prospective studies to show the safety, efficacy, and success and complication rates for USG blocks, USG RA theoretically could have less risk for neurologic symptoms, except for those induced by LA (less likely perineurally, much more likely intraneurally). The next "quantum leap" lies in reducing LA concentrations and augmenting anesthetic-analgesic effects with perineural additives (including clonidine, buprenorphine, and likely low-dose dexamethasone). Since 2005, perineural catheters have been an analgesic option that offers improved pain relief among other benefits, and are now being used at home. It is clear that patients benefit greatly from a single injection and continuous nerve block for postoperative pain management,but the financial and logistical aspects need to be resolved, not to mention the phrenic hemiparesis coin toss. Whether combined perineural analgesic adjuvants prolong low-concentration LA nerve blocks sufficiently to render brachial plexus catheters as unnecessary would certainly represent another quantum leap.

Brachial plexus entrapment of interscalene nerve catheter after uncomplicated ultrasound-guided placement.

We report on the case of an entrapped interscalene nerve catheter in a 46-year-old male undergoing left shoulder arthroscopic lysis of adhesions for a frozen shoulder. The catheter was placed under ultrasound guidance without any apparent complications. The continuous interscalene nerve block was successfully used as the primary anesthetic and for postoperative pain management. Upon attempted catheter removal, the patient experienced severe pain and paresthesias. Fluoroscopy revealed possible brachial plexus involvement, and surgery was performed to extract the catheter, which had become hooked and entrapped around the C5 nerve root and sheath.

Selective local anesthetic placement using ultrasound guidance and neurostimulation for infraclavicular brachial plexus block.

BACKGROUND: In this study, we performed the infraclavicular block with combined ultrasound guidance and neurostimulation to selectively target cords to compare the success rates of placing a single injection of local anesthetic either in a central or peripheral location. METHODS: Two hundred eighteen patients were enrolled in a consecutive, prospective study. Patients were randomized to injection of local anesthetic either centrally (posterior cord) or peripherally (medial or lateral cord) using ultrasound guidance and neurostimulation. Supervised senior anesthesiology residents or attending anesthesiologists performed the blocks. Both intent-to-treat and treatment-received analyses were used to compare central and peripheral placement efficacy. RESULTS: The overall success rate was significantly higher for the central placements than peripheral placements (96% vs 85%, P = 0.004). Individual cord success rates were as follows: posterior 99%, lateral 92%, and medial 84% (P = 0.001). The central group required attending physician intervention more frequently (27% vs 6%, P < 0.001). Postoperative pain scores of < or =3 were more likely with central placement (100% vs 94%, P = 0.012). CONCLUSION: Central placement of a single injection of local anesthetic targeted at the posterior cord resulted in a higher success rate for infraclavicular block.