A Randomized Double-Blinded Trial on the Effects of Ultrasound Transducer Orientation on Teaching and Learning Ultrasound-Guided Regional Anesthesia.

OBJECTIVES: Learning ultrasound-guided regional anesthesia skills, especially needle/ beam alignment, can be especially difficulty for trainees, who can often become frustrated. We hypothesized that teaching novices to orient the transducer and needle perpendicular to their shoulders will improve performance on a standardized task, compared to holding the transducer and needle parallel to the shoulders. METHODS: This study compared the effects of transducer orientation on trainees' ability to complete a standardized ultrasound-guided nerve block simulation. The time to task completion and percentage of the attempt time without adequate needle visualization were measured. Participants were right-handed healthy adults with no previous ultrasound experience and were randomly assigned to training in either transducer and needle alignment in a coronal plane, parallel to the shoulders (parallel group) or transducer and needle alignment in a sagittal plane, perpendicular to the shoulders (perpendicular group). Participants used ultrasound to direct a needle to 3 targets in a standardized gelatin phantom and repeated this task 3 times. Their efforts were timed and evaluated by an assessor, who was blinded to group assignment. RESULTS: Data were analyzed on 28 participants. The perpendicular group was able to complete the task more quickly (P < .001) and with a smaller proportion of time lost to inadequate needle visualization (P < .001). CONCLUSIONS: Ultrasound-guided regional anesthesia trainees complete a standardized task more quickly and efficiently when instructed to hold the transducer and needle in an orientation perpendicular to their shoulders.

A Randomized Controlled Trial Evaluating the See, Tilt, Align, and Rotate (STAR) Maneuver on Skill Acquisition for Simulated Ultrasound-Guided Interventional Procedures.

OBJECTIVES: Achieving the best view of the needle and target anatomy when performing ultrasound-guided interventional procedures requires technical skill, which novices may find difficult to learn. We hypothesized that teaching novice performers to use 4 sequential steps (see, tilt, align, and rotate [STAR] method) to identify the needle under ultrasound guidance is more efficient than training with the commonly described probe movements of align, rotate, and tilt (ART). METHODS: This study compared 2 instructional methods for transducer manipulation including alignment of a probe and needle by novices during a simulated ultrasound-guided nerve block. Right-handed volunteers between the ages of 18 and 55 years who had no previous ultrasound experience were recruited and randomized to 1 of 2 groups; one group was trained to troubleshoot misalignment with the ART method, and the other was trained with the new STAR maneuver. Participants performed the task, consisting of directing a needle in plane to 3 targets in a standardized gelatin phantom 3 times. The performance assessor and data analyst were blinded to group assignment. RESULTS: Thirty-five participants were recruited. The STAR group was able to complete the task more quickly (P < .001) and visualized the needle in a greater proportion of the procedure time (P = .004) compared to the ART group. All STAR participants were able to complete the task, whereas 41% of ART participants abandoned the task (P = .003). CONCLUSIONS: Novices are able to complete a simulated ultrasound-guided nerve block more quickly and efficiently when trained with the 4-step STAR maneuver compared to the ART method.

A randomized clinical trial comparing the effectiveness of ultrasound guidance versus nerve stimulation for lateral popliteal-sciatic nerve blocks in obese patients.

OBJECTIVES: Ultrasound guidance may decrease the procedural time for many peripheral nerve blocks compared to nerve stimulation, but these studies have generally excluded obese patients. This single-blinded randomized clinical trial was designed to compare procedural times and related outcomes for ultrasound- versus nerve stimulation-guided lateral popliteal-sciatic nerve blockade specifically in obese patients. METHODS: With Institutional Review Board approval and informed consent, patients with a body mass index greater than 30 kg/m(2) who were scheduled for foot/ankle surgery and desiring a peripheral nerve block were offered enrollment. Study patients were randomly assigned to receive a lateral popliteal-sciatic nerve block under either ultrasound or nerve stimulation guidance. The patient and assessor were blinded to group assignment. The primary outcome was procedural time in seconds. Secondary outcomes included number of needle redirections, procedure-related pain, patient satisfaction with the block, success rate, sensory and motor onset times, block duration, and complication rates. RESULTS: Twenty-four patients were enrolled and completed the study. All patients had successful nerve blocks. The mean procedural times (SD) were 577 (57) seconds under nerve stimulation and 206 (40) seconds with ultrasound guidance (P< .001; 95% confidence interval for difference, 329-412 seconds). Patients in the ultrasound group had fewer needle redirections and less procedure-related pain, required less opioids, and were more satisfied with their block procedures. There were no statistically significant differences in other outcomes. CONCLUSIONS: The results of this study show that, for obese patients undergoing lateral popliteal-sciatic nerve blocks, ultrasound guidance reduces the procedural time and procedure-related pain and increases patient satisfaction compared to nerve stimulation while providing similar block characteristics.

A triple-masked, randomized controlled trial comparing ultrasound-guided brachial plexus and distal peripheral nerve block anesthesia for outpatient hand surgery.

Background. For hand surgery, brachial plexus blocks provide effective anesthesia but produce undesirable numbness. We hypothesized that distal peripheral nerve blocks will better preserve motor function while providing effective anesthesia. Methods. Adult subjects who were scheduled for elective ambulatory hand surgery under regional anesthesia and sedation were recruited and randomly assigned to receive ultrasound-guided supraclavicular brachial plexus block or distal block of the ulnar and median nerves. Each subject received 15 mL of 1.5% mepivacaine at the assigned location with 15 mL of normal saline injected in the alternate block location. The primary outcome (change in baseline grip strength measured by a hydraulic dynamometer) was tested before the block and prior to discharge. Subject satisfaction data were collected the day after surgery. Results. Fourteen subjects were enrolled. Median (interquartile range [IQR]) strength loss in the distal group was 21.4% (14.3, 47.8%), while all subjects in the supraclavicular group lost 100% of their preoperative strength, P = 0.001. Subjects in the distal group reported greater satisfaction with their block procedures on the day after surgery, P = 0.012. Conclusion. Distal nerve blocks better preserve motor function without negatively affecting quality of anesthesia, leading to increased patient satisfaction, when compared to brachial plexus block.

Ultrasound-guided parasacral approach to the sciatic nerve block in children.

BACKGROUND: The parasacral (PS) approach to sciatic nerve blockade has the potential for safe and effective use in children, but has never been studied in this population. Its potential advantages include increased posterior cutaneous nerve block reliability, potential for hip joint analgesia, and decreased nerve depth, making ultrasound guidance easier. OBJECTIVE: To assess the efficacy of an ultrasound-guided PS sciatic nerve block in children. METHODS: Nineteen patients, 1-16 years old, scheduled for lower limb surgery with peripheral nerve blockade (PNB) were prospectively enrolled. A PS sciatic block was performed using both ultrasound guidance and nerve stimulation, and 0.5 ml·kg(-1) ropivacaine 0.2% (maximum 20 ml) was administered. Patient demographics, the time to perform the block, the lowest intensity of nerve stimulation, evoked response, identification of gluteal arteries, and amount of narcotic given were recorded. Postoperatively, pain scores, block success or failure, block duration, and complications were recorded. RESULTS: The block was performed using the PS approach in 95% of the cases. The success rate was 100% in the PS sciatic blocks performed. The pain scores for all patients in the first postsurgical hour were zero, except one patient that had a pain score of 3 of 10 at 30 min; his pain improved to 0 of 10 after administration of one dose of fentanyl and distraction techniques. The blocks lasted 17.3 ± 5.4 h. No complications were identified. CONCLUSION: The PS approach is an effective option for sciatic nerve blockade to provide postoperative pain relief in children having lower extremity surgery.