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

Comparison of Two Different Techniques in Ultrasound Guided Infraclavicular Block: Jedi and Classic Grip

Background: The widespread use of ultrasonography in peripheral nerve blocks requires an assistant. Pappin et al. described the “Jedi grip” technique in which the practitioner works alone by controlling the ultrasound prob with one hand and the needle and injector with the other. In this study, we aimed to compare the block characteristics of the “Jedi grip” technique with the classical technique that performed with an assistant. Methods: 78 patients were included in our study. They were randomly divided into two groups (Group I: Jedi grip and Group II: Classical grip technique). Local anesthetic was applied to both groups from 10 ml of 0.5% bupivacaine +10 ml of 2% prilocaine mixture. The block characteristics were evaluated and recorded every 5 minutes for the first 30 minutes after each block. When the sensory block score was 7 and the total score was 14 or above, the block was considered successful, and the patient was ready for surgery. Results: There was no significant difference between the groups in terms of block characteristics such as block pain, number of attempts, arterial puncture, sensory and motor block onset and regression times, time to be ready for surgery, tourniquet pain, use of additional anesthesia method, use of postoperative analgesia. The duration of block application was 158±47 sec in the Jedi group and 121±83 sec in the control group. Conclusion: The Jedi grip technique has been found to be applicable with the same confidence compared to the classical method in terms of block success and complications.

Prediction of nerve block success using ultrasonographic parameters: A preliminary animal study

This study aimed to evaluate the diagnostic value of ultrasonographic parameters as an indicator for predicting regional nerve block success. Ultrasound-guided sciatic nerve block was performed in seven dogs using either 2% mepivacaine (nerve-block group) or saline (sham-block group). The cross-sectional area (CSA), nerve blood flow (NBF), and shear wave velocity (SWV) of the sciatic nerve (SWVN), SWV of the biceps femoris muscle (SWVM), and their ratio (SWVNMR) were measured at 0, 30, 60, and 90 min after the nerve block as well as the change rate of each parameter from the baseline. A receiver operating characteristic (ROC) curve analysis was performed to determine the diagnostic value of each parameter in the prediction of nerve block success. No significant changes were observed in the CSA or NBF in association with the nerve block. The SWVN and SWVNMR in the nerve-block group were significantly higher than those in the sham-block group at 90 min and at 30, 60, and 90 min, respectively (p < 0.05). The change rates of SWVN and SWVNMR in the nerve-block group were significantly higher than those in the sham-block group at all time points (p < 0.05). The ROC curve analysis showed that SWVN had a moderate diagnostic accuracy (area under the curve [AUC], 0.779), whereas SWVNMR and change rates of SWVN and SWVNMR had a high diagnostic accuracy (AUC, 0.947, 0.998, and 1.000, respectively). Ultrasonographic evaluation of the SWVN and SWVNMR could be used as indicators for predicting nerve block success.

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 minutes 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 minutes as judged by median (10 th, 90 th 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

Comparative of the Effectiveness of Different Objective Method for Infraclavicular Brachial Plexus Block Success; Which One of Them is A Reliable and Early Indicator?

ABSTRACT BACKGROUND Traditional methods that evaluate the success of peripheral nerve block have been replaced by methods that allow objective evaluations over time. Multiple objective techniques for peripheral nerve block have been discussed in the literature. OBJECTIVE This study aims to investigate whether perfusion index (PI), non-invasive tissue hemoglobin monitoring (SpHb), tissue oxygen saturation (StO2), tissue hemoglobin index (THI) and body temperature are reliable and objective methods to evaluate the adequacy of infraclavicular blockage. DESIGN A prospective observational study. SETTING Single center, Department of Anesthesiology, Harran University Medical Faculty, Turkey, from February 2019 to December 2019. PATIENTS A total of 100 patients scheduled to undergo forearm surgery. INTERVENTION Ultrasound-guided infraclavicular block (ICB) in 100 patients undergoing forearm surgery. MAIN OUTCOME MEASURES PI, SpHb, StO2, THI and Body Temperature measurements were recorded 5 min before the block procedure, right after the procedure, and until the 25th minute after the procedure at 5-min intervals. These values were compared between the blocked limbs and non-blocked limbs while being statistically compared between the successful and failed block groups. RESULTS Although there were significant differences between the groups of blocked extremity and non-blocked extremity in terms of StO2 (P = 0.001), THI (P = 0.001), PI (P = 0.001) and body temperature (P = 0.001), there was no significant difference between these groups in terms of SpHb (P > 0.05). Moreover, a significant difference was detected between the groups of successful block and failed block in terms of StO2 (P = 0.002), PI (P = 0.002) and body temperature (P = 0.005), while there was no significant difference between these groups in terms of THI (P > 0.05) and SpHb (P > 0.05). CONCLUSION StO2, PI and body temperature measurements are the simple, objective, noninvasive techniques to be used to evaluate success of block procedures. According to The receiver operating characteristic (ROC) analysis, StO2 is the specific parameter with the highest sensitivity among these parameters.

Paracoracoid versus Costoclavicular Approach to Infraclavicular Block: A Prospective, Two Arm, Parallel design, Single-centre Randomized Controlled Trial

ABSTRACTIntroductionParacoracoid approach to the brachial plexus block is the conventional infraclavicular technique for upper limb surgeries. In this approach, the ultrasound transducer is placed in the parasagittal plane below the clavicle, medial to the coracoid process. In this view, three cords are separated from each other and are rarely visualized in a single ultrasound window. In the costoclavicular approach, the ultrasound transducer is placed parallel to and below the clavicle. In this view, the cords are clustered together, at a more superficial level. We conducted a randomized controlled trial to compare these two infraclavicular brachial plexus approaches.MethodsSeventy patients were randomized to receive either a paracoracoid or costoclavicular infraclavicular block. Both groups received 35 ml of 0.5% ropivacaine under ultrasound guidance. The primary outcome was sensory block onset time while secondary outcomes included performance times, complications during block insertion (paresthesia, vascular puncture, pleural puncture), block failure, patient satisfaction, and postoperative complications. Telephone follow-up was done 24 h and 7 days later.ResultsSensory block onset time was significantly shorter in the paracoracoid group 18.7 (4.4) min versus 22.2 (6.2) min (p=0.045). Block success at 30 minutes was the same between both groups. There was no difference in any secondary outcomes.ConclusionsThis randomized controlled trial demonstrated that the novel costoclavicular approach to the infraclavicular brachial plexus block had similar procedure time, block success and similar complication rates for upper limb surgery when compared to the traditional paracoracoid technique. However, it resulted in longer sensory block onset time.

Optimal local anesthetic regimen for saddle block in ambulatory anorectal surgery: an evidence-based systematic review

BackgroundAmbulatory anorectal surgery requires an anesthetic of short duration but profound depth. Saddle block anesthesia (SBA) can provide dense sacral anesthesia with minimal motor blockade, but the ideal local anesthetic agent remains undefined. This systematic review aims to identify the optimal SBA regimen for ambulatory anorectal surgery.MethodsWe sought randomized trials examining SBA for ambulatory anorectal surgery and stratified patients into four subgroups according to local anesthetic type and dose: (1) longer acting, higher dose; (2) longer acting, lower dose; (3) shorter acting, higher dose; and (4) shorter acting, lower dose. Longer acting agents included bupivacaine and levobupivacaine; shorter acting agents included chloroprocaine, mepivacaine, and prilocaine. Lower dose was defined as ≤5 mg and ≤20 mg for longer and shorter acting local anesthetics, respectively. The primary outcome was time to discharge; secondary outcomes included times to sensory and motor block regression, urine voiding, and ambulation, as well as block success.ResultsA total of 11 trials (1063 patients) were included. Overall study quality and reporting consistency was poor. Doses ranged from 1.5–7.5 mg to 3–30 mg of longer and shorter acting local anesthetics, respectively. Hyperbaric local anesthetics were used in eight trials (953 patients, 86%). The median time to discharge appeared similar across all subgroups with an overall time of 182 (IQR 102) min. The use of long-acting, lower dose regimens was associated with a faster median time to motor block regression. Block success approached 99% among all trials.ConclusionsThere is presently insufficient qualitative and quantitative evidence to identify an optimal SBA regimen for ambulatory anorectal surgery. Nonetheless, we found that doses as low as 1.5 and 3 mg of longer and shorter acting hyperbaric local anesthetics, respectively, can achieve effective and reliable SBA with timely hospital discharge. Despite similar discharge times, longer acting, lower dose local anesthetics may produce faster motor block regression following SBA for ambulatory anorectal surgery.