Different Learning Curves for Axillary Brachial Plexus Block: Ultrasound Guidance versus Nerve Stimulation

Impact of Regional Block Failure in Ambulatory Hand Surgery on Patient Management: A Cohort Study

Regional anesthesia (RA) is an anesthetic technique essential for the performance of ambulatory surgery. Failure rates range from 6% to 20%, and the consequences of these failures have been poorly investigated. We determined the incidence and the impact of regional block failure on patient management in the ambulatory setting. This retrospective cohort study includes all adult patients who were admitted to a French University Hospital (Hôpital Saint-Antoine, AP-HP) between 1 January 2016 and 31 December 2017 for unplanned ambulatory distal upper limb surgery. Univariate and stepwise multivariate analyses were performed to determine factors associated with block failure. Among the 562 patients included, 48 (8.5%) had a block failure. RA failure was associated with a longer surgery duration (p = 0.02), more frequent intraoperative analgesics administration (p < 0.01), increased incidence of unplanned hospitalizations (p < 0.001), and a 39% prolongation of Post-Anesthesia Care Unit (PACU) length of stay (p < 0.0001). In the multivariate analysis, the risk factors associated with block failure were female sex (p = 0.04), an American Society of Anesthesiologists (ASA) score > 2 (p = 0.03), history of substance abuse (p = 0.01), and performance of the surgery outside of the specific ambulatory surgical unit (p = 0.01). Here, we have documented a significant incidence of block failure in ambulatory hand surgery, with impairment in the organization of care. Identifying patients at risk of failure could help improve their management, especially by focusing on providing care in a dedicated ambulatory circuit.

Analysis of previous training with simulated models on the success rate of ultrasound-guided supraclavicular block. Prospective cohort study

INTRODUCTION

The teaching based on simulation and acquisition of skills is changing the paradigm of education and restructuring the clinical residences, with the aim of acquiring better skills, increasing procedural success, reducing complications, as well as providing safe, effective, and efficient and focused care of the patient. Peripheral nerve blocks have advanced as techniques for anatomical repairs, use of neurostimulator, and ultrasound. The posgraduate anaesthesiology program implemented a teaching program that included phases of theoretical teaching, training with simulated models, and application in real scenarios.

OBJECTIVE

To analyse the success, the management of the ultrasound equipment and the incidence of complications of ultrasound-guided supraclavicular blocks (BSE) in the clinical scenario, performed by residents of anaesthesiology previously trained with a theoretical and simulated model.

METHODS

Prospective cohort study among residents of anaesthesiology (R1, R2, R3, R4), who received previous theoretical-practical training on simulated models. The evaluation was performed by expert anaesthesiologists, with video analysis of the ultrasound screen performed at the time of BSE initiation.

RESULTS

The evaluation included 16 residents, who performed 156 BSE. None had previous experience in ultrasound-guided blocks. The success of the block was 96.15%. The team management was excellent (from 86% to 95%), with no significant differences among the residents. (P=.61) The incidence of complications was 0.64%, corresponding to arterial puncture.

CONCLUSIONS

In BSE, previous training with a theoretical and simulated model could increase the probability of success and reduce complications. With adequate training, first year residents managed to successfully carry out the procedure.

Ultrasound-Guided Needle Technique Accuracy: Prospective Comparison of Passive Magnetic Tracking Versus Unassisted Echogenic Needle Localization

Background and Objectives

Ultrasound-guided regional anesthesia facilitates an approach to sensitive targets such as nerve clusters without contact or inadvertent puncture. We compared accuracy of needle placement with a novel passive magnetic ultrasound needle guidance technology (NGT) versus conventional ultrasound (CU) with echogenic needles.

Methods

Sixteen anesthesiologists and 19 residents performed a series of 16 needle insertion tasks each, 8 using NGT (n = 280) and 8 using CU (n = 280), in high-fidelity porcine phantoms. Tasks were stratified based on aiming to contact (target-contact) or place in close proximity with (target-proximity) targets, needle gauge (no. 18/no. 22), and in-plane (IP) or out-of-plane (OOP) approach. Distance to the target, task completion by aim, number of passes, and number of tasks completed on the first pass were reported.

Results

Needle guidance technology significantly improved distance, task completion, number of passes, and completion on the first pass compared with CU for both IP and OOP approaches (P ≤ 0.001). Average NGT distance to target was lower by 57.1% overall (n = 560, 1.5 ± 2.4 vs 3.5 ± 3.7 mm), 38.5% IP (n = 140, 1.6 ± 2.6 vs 2.6 ± 2.8 mm), and 68.2% OOP (n = 140, 1.4 ± 2.2 vs 4.4 ± 4.3 mm) (all P ≤ 0.01). Subgroup analyses revealed accuracy gains were largest among target-proximity tasks performed by residents and for OOP approaches. Needle guidance technology improved first-pass completion from 214 (76.4%) per 280 to 249 (88.9%) per 280, a significant improvement of 16.4% (P = 0.001).

Conclusions

Passive magnetic NGT can improve accuracy of needle procedures, particularly among OOP procedures requiring close approach to sensitive targets, such as nerve blocks in anesthesiology practice.

Anaesthesia in austere environments: literature review and considerations for future space exploration missions

Future space exploration missions will take humans far beyond low Earth orbit and require complete crew autonomy. The ability to provide anaesthesia will be important given the expected risk of severe medical events requiring surgery. Knowledge and experience of such procedures during space missions is currently extremely limited. Austere and isolated environments (such as polar bases or submarines) have been used extensively as test beds for spaceflight to probe hazards, train crews, develop clinical protocols and countermeasures for prospective space missions. We have conducted a literature review on anaesthesia in austere environments relevant to distant space missions. In each setting, we assessed how the problems related to the provision of anaesthesia (e.g., medical kit and skills) are dealt with or prepared for. We analysed how these factors could be applied to the unique environment of a space exploration mission. The delivery of anaesthesia will be complicated by many factors including space-induced physiological changes and limitations in skills and equipment. The basic principles of a safe anaesthesia in an austere environment (appropriate training, presence of minimal safety and monitoring equipment, etc.) can be extended to the context of a space exploration mission. Skills redundancy is an important safety factor, and basic competency in anaesthesia should be part of the skillset of several crewmembers. The literature suggests that safe and effective anaesthesia could be achieved by a physician during future space exploration missions. In a life-or-limb situation, non-physicians may be able to conduct anaesthetic procedures, including simplified general anaesthesia.

[Ultrasound guidance improves the success rate of axillary plexus block: a meta-analysis]

OBJECTIVE

To evaluate the value of real-time ultrasound (US) guidance for axillary brachial plexus block (AXB) through the success rate and the onset time.

METHODS

The meta-analysis was carried out in the Anesthesiology Department of the Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China. A literature search of Medline, Embase, Cochrane database from the years 2004 to 2014 was performed. The literature searches were carried out using medical subject headings and free-text word: "axilla", "axillary", "brachial plexus", "ultrasonography", "ultrasound", "ultrasonics". Two different reviewers carried out the search and evaluated studies independently.

RESULTS

Seven randomized controlled trials, one cohort study and three retrospective studies were included. A total of 2042 patients were identified. 1157 patients underwent AXB using US guidance (US group) and the controlled group included 885 patients (246 patients using traditional approach (TRAD) and 639 patients using nerve stimulation (NS)). Our analysis showed that the success rate was higher in the US group compared to the controlled group (90.64% vs. 82.21%, p<0.00001). The average time to perform the block and the onset of sensory time were shorter in the US group than the controlled group.

CONCLUSION

The present study demonstrated that the real-time ultrasound guidance for axillary brachial plexus block improves the success rate and reduce the mean time to onset of anesthesia and the time of block performance.

Sonographic identification of peripheral nerves in the forearm

Background:

With the growing utilization of ultrasonography in emergency medicine combined with the concern over adequate pain management in the emergency department (ED), ultrasound guidance for peripheral nerve blockade in ED is an area of increasing interest. The medical literature has multiple reports supporting the use of ultrasound guidance in peripheral nerve blocks. However, to perform a peripheral nerve block, one must first be able to reliably identify the specific nerve before the procedure.

Objective:

The primary purpose of this study is to describe the number of supervised peripheral nerve examinations that are necessary for an emergency medicine physician to gain proficiency in accurately locating and identifying the median, radial, and ulnar nerves of the forearm via ultrasound.

Methods:

The proficiency outcome was defined as the number of attempts before a resident is able to correctly locate and identify the nerves on ten consecutive examinations. Didactic education was provided via a 1 h lecture on forearm anatomy, sonographic technique, and identification of the nerves. Participants also received two supervised hands-on examinations for each nerve. Count data are summarized using percentages or medians and range. Random effects negative binomial regression was used for modeling panel count data.

Results:

Complete data for the number of attempts, gender, and postgraduate year (PGY) training year were available for 38 residents. Nineteen males and 19 females performed examinations. The median PGY year in practice was 3 (range 1–3), with 10 (27%) in year 1, 8 (22%) in year 2, and 19 (51%) in year 3 or beyond. The median number (range) of required supervised attempts for radial, median, and ulnar nerves was 1 (0–12), 0 (0–10), and 0 (0–17), respectively.

Conclusion:

We can conclude that the maximum number of supervised attempts to achieve accurate nerve identification was 17 (ulnar), 12 (radial), and 10 (median) in our study. The only significant association was found between years in practice and proficiency (P = 0.025). We plan to expound upon this research with an additional future study that aims to assess the physician's ability to adequately perform peripheral nerve blocks in efforts to decrease the need for more generalized procedural sedation.

Ultrasound guidance improves the success rate of axillary plexus block: a meta-analysis

OBJECTIVE

To evaluate the value of real-time ultrasound (US) guidance for axillary brachial plexus block (AXB) through the success rate and the onset time.

METHODS

The meta-analysis was carried out in the Anesthesiology Department of the Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China. A literature search of Medline, EMBASE, Cochrane database from the years 2004 to 2014 was performed. The literature searches were carried out using medical subject headings and free-text word: "axilla", "axillary", "brachial plexus", "ultrasonography", "ultrasound", "ultrasonics". Two different reviewers carried out the search and evaluated studies independently.

RESULTS

Seven randomized controlled trials, one cohort study and three retrospective studies were included. A total of 2042 patients were identified. 1157 patients underwent AXB using US guidance (US group) and the controlled group included 885 patients (246 patients using traditional approach (TRAD) and 639 patients using nerve stimulation (NS)). Our analysis showed that the success rate was higher in the US group compared to the controlled group (90.64% vs. 82.21%, p<0.00001). The average time to perform the block and the onset of sensory time were shorter in the US group than the controlled group.

CONCLUSION

The present study demonstrated that the real-time ultrasound guidance for axillary brachial plexus block improves the success rate and reduce the mean time to onset of anesthesia and the time of block performance.

An evaluation of brachial plexus block using a nerve stimulator versus ultrasound guidance: A randomized controlled trial

Background and Aims:

This study was carried out to evaluate the difference in efficacy, safety, and complications of performing brachial plexus nerve blocks by using a nerve locator when compared to ultrasound (US) guidance.

Material and Methods:

A total of 102 patients undergoing upper limb surgery under supraclavicular brachial plexus blocks were randomly divided into two groups, one with US and the other with nerve stimulator (NS). In Group US, “Titan” Portable US Machine, Sonosite, Inc. Kensington, UK with a 9.0 MHz probe was used to visualize the brachial plexus and 40 ml of 0.25% bupivacaine solution was deposited around the brachial plexus in a graded manner. In Group (NS), the needle was inserted 1-1.5 cm above mid-point of clavicle. Once hand or wrist motion was detected at a current intensity of less than 0.4 mA 40 ml of 0.25% bupivacaine was administered. Onset of sensory and motor block of radial, ulnar and median nerves was recorded at 5-min intervals for 30-min. Block execution time, duration of block (time to first analgesic), inadvertent vascular puncture, and neurological complications were taken as the secondary outcome variables.

Results:

About 90% patients in US group and 73.1% in NS group, had successful blocks P = 0.028. The onset of block was faster in the Group US as compared to Group NS and this difference was significant (P 0.007) only in the radial nerve territory. The mean duration of the block was longer in Group US, 286.22 ± 42.339 compared to 204.37 ± 28.54-min in Group NS (P < 0.05). Accidental vascular punctures occurred in 7 patients in the NS group and only 1 patient in the US group.

Conclusion:

Ultrasound guidance for supraclavicular brachial plexus blockade provides a block that is faster in onset, has a better quality and lasts longer when compared with an equal dose delivered by conventional means.

Ultrasound-guided nerve blocks--is documentation and education feasible using only text and pictures?

PURPOSE

With the advancement of ultrasound-guidance for peripheral nerve blocks, still pictures from representative ultrasonograms are increasingly used for clinical procedure documentation of the procedure and for educational purposes in textbook materials. However, little is actually known about the clinical and educational usefulness of these still pictures, in particular how well nerve structures can be identified compared to real-time ultrasound examination. We aimed to quantify gross visibility or ultrastructure using still picture sonograms compared to real time ultrasound for trainees and experts, for large or small nerves, and discuss the clinical or educational relevance of these findings.

MATERIALS AND METHODS

We undertook a clinical study to quantify the maximal gross visibility or ultrastructure of seven peripheral nerves identified by either real time ultrasound (clinical cohort, n = 635) or by still picture ultrasonograms (clinical cohort, n = 112). In addition, we undertook a study on test subjects (n = 4) to quantify interobserver variations and potential bias among expert and trainee observers.

RESULTS

When comparing real time ultrasound and interpretation of still picture sonograms, gross identification of large nerves was reduced by 15% and 40% by expert and trainee observers, respectively, while gross identification of small nerves was reduced by 29% and 66%. Identification of within-nerve ultrastructure was even less. For all nerve sizes, trainees were unable to identify any anatomical structure in 24 to 34%, while experts were unable to identify anything in 9 to 10%.

CONCLUSION

Exhaustive ultrasonography experience and real time ultrasound measurements seem to be keystones in obtaining optimal nerve identification. In contrast the use of still pictures appears to be insufficient for documentation as well as educational purposes. Alternatives such as video clips or enhanced picture technology are encouraged instead of still pictures extracted from basic ultrasonograms.

Use of needle enhancing software to improve injection technique amongst inexperienced anaesthetists performing ultrasound-guided peripheral nerves blocks in dogs

OBJECTIVE

To determine if the use of needle enhancing software facilitate injection technique in ultrasound-guided peripheral nerve blocks.

STUDY DESIGN

Prospective, blinded, randomized controlled trial.

ANIMALS

Eight hind limbs from canine cadavers.

METHODS

The limbs were randomly allocated to two groups; software on (group I) and software off (group II). Eight anaesthetists with no previous experience of ultrasound-guided regional anaesthesia were recruited. Thirty-six procedures were carried out (18 per group). After sciatic nerve visualisation via ultrasonography, the anaesthetist introduced a needle guided by ultrasonography. When the tip of the needle was considered by the anaesthetist to be as close as possible to the nerve without touching it, 0.05 mL of methylene blue dye was injected. Parameters evaluated included: number of attempts to visualise the needle with ultrasonography, time spent to perform the technique, subjective evaluation of ease of needle visualisation, proximity of the tip of the needle to the nerve, and, at dissection of the leg, inoculation site of the dye in relation to the nerve.

RESULTS

Significant differences between groups were identified in relation to the number of attempts (group I: median 1, IQR: 1 - 1 attempts versus group II: median 1, IQR: 1 - 4 attempts, p = 0.019), and the relationship between the dye and the nerve during hind limb dissection (72.2% of the nerves were stained in group I versus 16.6% in group II, p = 0.003). No significant difference between groups was observed with respect to the time taken to perform the procedure (group I: median 25.5, IQR: 18.4 - 44.3 seconds versus group II: median 35.7, IQR: 18.6-78.72 seconds, p = 0.31), subjective evaluation of the needle visualization (p = 0.45) or distance between the tip of the needle and the nerve as measured from the ultrasound screen (p = 0.23).

CONCLUSIONS AND CLINICAL RELEVANCE

This study identified greater success rate in nerve staining when the needle enhancing software was used. The results suggest that the use of this technique could improve injection technique amongst inexperienced anaesthetists performing ultrasound-guided peripheral nerve blocks in dogs.