Medical Student Instruction in Peripheral Nerve Blockade Utilizing Fresh Cadaver Limbs in a Simulation Center.

Background: Ultrasound imaging is increasingly used in medical practice, but many institutions have room for growth regarding its incorporation into medical education. An elective hands-on course was developed for preclinical medical students using ultrasound to review and enhance their understanding of anatomy as well as to teach ultrasound-guided nerve blocks on cadaver extremities. The hypothesis was that after 3 instructional sessions students would be able to identify 6 anatomic structures, representing 3 types of tissue, in cadaver upper extremities. Methods: Students received didactic instruction on ultrasound and regional anatomy at the beginning of each class, followed by hands-on practice, including ultrasound use with phantom task trainers, live models, and fresh cadaver limbs. The primary outcome was the students' ability to correctly identify anatomic structures using ultrasound. Secondary outcomes included their ability to perform a simulated nerve block in the cadaver extremities in comparison with a standardized checklist, as well as their response to a post-course survey. Results: Overall, the students had a 91% success rate in identifying anatomic structures and showed capability of performing simulated nerve block with occasional instructor prompting. The post-course survey revealed that the students felt strongly that both the ultrasound and cadaveric components of the course were beneficial to their education. Conclusion: Ultrasound instruction with live models and fresh cadaver extremities in a medical student elective course resulted in a high degree of recognition of anatomic structures, as well as permitted a valued clinical correlation in the form of simulated peripheral nerve blockade.

Effect of superior trunk block on diaphragm function and respiratory parameters after shoulder surgery.

BACKGROUND: The interscalene brachial plexus block has been used effectively for intraoperative and postoperative analgesia in patients undergoing shoulder surgery, but it is associated with high rates of diaphragmatic dysfunction. Performing the block more distally, at the level of the superior trunk, may reduce the incidence of phrenic nerve palsy. We hypothesized that superior trunk block would result in diaphragmatic paralysis rate of less than 20%. METHODS: 30 patients undergoing arthroscopic shoulder surgery received superior trunk block under ultrasound guidance. Measurements of diaphragm excursion were determined with ultrasound prior to the block, 15 min after the block, and postoperatively in phase II of postanesthesia care unit, in conjunction with clinical parameters of respiratory function. RESULTS: 10 patients (33.3%, 95% CI 17.3% to 52.8%) developed complete hemidiaphragmatic paralysis at the postoperative assessment. An additional eight patients (26.7%) developed paresis without paralysis. Of the 18 patients with diaphragm effects, seven (38.9%) reported dyspnea. 83.3% of patients with abnormal diaphragm motion (56.7% of the total sample) had audibly reduced breath sounds on auscultation. Oxygen saturation measurements did not correlate with diaphragm effect and were not significantly reduced by the postoperative assessment. CONCLUSION: Although injection of local anesthetic at the superior trunk level is associated with less diaphragmatic paralysis compared with traditional interscalene block, a significant portion of patients will continue to have ultrasonographic and clinical evidence of diaphragmatic weakness or paralysis.

Non-Fellowship regional anesthesia training and assessment: an international Delphi study on a consensus curriculum.

BACKGROUND AND OBJECTIVES: While there are several published recommendations and guidelines for trainees undertaking subspecialty Fellowships in regional anesthesia, a similar document describing a core regional anesthesia curriculum for non-fellowship trainees is less well defined. We aimed to produce an international consensus for the training and teaching of regional anesthesia that is applicable for the majority of worldwide anesthesiologists. METHODS: This anonymous, electronic Delphi study was conducted over two rounds and distributed to current and immediate past (within 5 years) directors of regional anesthesia training worldwide. The steering committee formulated an initial list of items covering nerve block techniques, learning objectives and skills assessment and volume of practice, relevant to a non-fellowship regional anesthesia curriculum. Participants scored these items in order of importance using a 10-point Likert scale, with free-text feedback. Strong consensus items were defined as highest importance (score ≥8) by ≥70% of all participants. RESULTS: 469 participants/586 invitations (80.0% response) scored in round 1, and 402/469 participants (85.7% response) scored in round 2. Participants represented 66 countries. Strong consensus was reached for 8 core peripheral and neuraxial blocks and 17 items describing learning objectives and skills assessment. Volume of practice for peripheral blocks was uniformly 16-20 blocks per anatomical region, while ≥50 neuraxial blocks were considered minimum. CONCLUSIONS: This international consensus study provides specific information for designing a non-fellowship regional anesthesia curriculum. Implementation of a standardized curriculum has benefits for patient care through improving quality of training and quality of nerve blocks.

Osteonecrosis of Bilateral Mandibular Tori After Direct Laryngoscopy.

A 36-year-old man underwent direct laryngoscopy with routine general anesthesia for a knee procedure. Several days later, he experienced pain involving an ulceration along the medial aspect of the right mandible in the floor of the mouth. This evolved to a painful bony mass, and subsequently, a bony sequestrum was spontaneously shed. The initially misdiagnosed pathologic process occurred several more times on both sides of the mouth. A computed tomography scan eventually revealed large bilateral mandibular tori, a feature that likely predisposed the patient to this course of events. Pain in the floor of the mouth after airway manipulation should be carefully evaluated and the possibility of osteonecrosis considered.

Liposomal bupivacaine infiltration in the surgical site for analgesia after rotator cuff repair: a randomized, double-blinded, placebo-controlled trial.

INTRODUCTION: Arthroscopic rotator cuff repair is among the most painful of orthopedic surgeries. Liposomal bupivacaine is Food and Drug Administration approved for administration into surgical sites to provide postsurgical analgesia and has been used to address postoperative pain after many types of surgery, including total shoulder arthroplasty. However, its efficacy for pain control after rotator cuff repair is unclear. METHODS: In this randomized, double-blind, placebo-controlled trial, we compared liposomal bupivacaine with an equivalent volume of saline injected into the subacromial space and arthroscopy portal sites in patients undergoing rotator cuff repair under the interscalene block with sedation. The primary outcome measure was numeric rating pain score at the time of block resolution, as reported during the follow-up phone call on postoperative day 1. Secondary outcomes included mean pain scores at rest as well as oral morphine equivalent requirements on postoperative days 1, 2, and 3. This study provides Level 1 evidence. RESULTS: There were no statistically significant differences in the primary outcome of numeric rating pain scores on resolution of the interscalene nerve block, nor in those reported on postoperative day 1 or 2. There was a minor but statistically significant difference in mean resting pain scores on day 3, though opioid consumption and patient satisfaction score did not differ between groups. In those instructed to perform passive range-of-motion exercises, there was no difference in reported mean pain scores among the groups. DISCUSSION: In this study of patients undergoing arthroscopic rotator cuff repair, we found no statistically significant difference in mean pain scores on interscalene block resolution, a result consistent with a number of studies investigating liposomal bupivacaine for total shoulder arthroplasty. A modest reduction in pain was evident only on day 3, and there was no impact on perioperative opioid requirements, opioid-related side effects, or pain with motion. Liposomal bupivacaine, when injected into the subacromial space and the tissues around the arthroscopy port sites, provided minimal improvement in pain control in this patient population.

Has the future arrived? Liposomal bupivacaine versus perineural catheters and additives for interscalene brachial plexus block.

PURPOSE OF REVIEW: Single injection interscalene block (ISB) provides effective analgesia for shoulder surgery. However, the duration of these is limited. This review summarizes the effectiveness of three potential means of extending the duration of analgesia: perineural infusion of local anesthetic agents, addition of adjuvant drugs to local anesthetics in single-injection nerve block, and utilization of liposomal bupivacaine in the surgical field or in the block itself. RECENT FINDINGS: Perineural infusion of local anesthetics with interscalene catheters provides superior pain relief with reduction of postoperative opioids. Both dexmedetomidine and dexamethasone effectively extend the duration of single injection ISB. Liposomal bupivacaine holds promise when injected perineurally in ISB, either as a sole agent or when mixed with standard bupivacaine. SUMMARY: Interscalene catheters, adjunctive drugs added to local anesthetics in single-injection interscalene brachial plexus blocks, or liposomal bupivacaine may be used to effectively prolong the duration of analgesia for shoulder surgery patients.

The Ultrasound Anatomy of Nerves in the Interscalene Groove: Can We Reliably Distinguish the Nerve Structures for Needle Placement During Nerve Blocks?

In the interscalene groove, nerve structures are in close proximity and may not be visible as separate structures, increasing the risk of insertion of the needle tip within the epineurium. We evaluated whether experienced regional anesthesiologists can distinguish between nerve elements lying in close proximity on ultrasound images.Brachial plexus elements from 4 nonpreserved cadavers were arranged in a water bath. Ultrasound images of the nerve roots and trunks were taken. Regional anesthesiologists and residents were asked whether they could distinguish the nerves as 2 separate structures and if they could identify a pair of nerve roots versus a single trunk.Attending anesthesiologists reported the ability to discriminate 2 nerve structures when a 2-mm space was arranged between them in 54% of images; however, when in direct contact, this recognition was significantly lower. The residents reported a higher ability to discriminate the 2 nerves in all scenarios. In addition, the attending anesthesiologists successfully identified paired nerve roots versus nerve trunks in 70% of the images, significantly higher than chance (P = 0.01), whereas the fraction of correct resident responses was not significantly different from guessing.When nerves were placed in close proximity, experienced regional anesthesiologists had difficulty identifying them as separate structures and were incorrect nearly one-third of the time in discriminating 2 closely positioned roots versus a nerve trunk. This underscores the importance of cautious needle insertion into the interscalene groove, where nerve elements are often juxtaposed one to another.

A review of peripheral nerve blocks for cesarean delivery analgesia.

Peripheral nerve blocks have a unique role in postcesarean delivery multimodal analgesia regimens. In this review article, options for peripheral nerve blocks for cesarean delivery analgesia will be reviewed, specifically paravertebral, transversus abdominis plane, quadratus lumborum, iliohypogastric and ilioinguinal, erector spinae, and continuous wound infiltration blocks. Anatomy, existing literature evidence, and specific areas in need of future research will be assessed. Considerations for local anesthetic toxicity, and for informed consent for these modalities in the context of emergency cesarean deliveries, will be presented.

A Porcine Model for Learning Ultrasound Anatomy of the Larynx and Ultrasound-Guided Cricothyrotomy.

BACKGROUND: Difficulty with tracheal intubation is the most common cause of serious adverse respiratory events during anesthesia. Cricothyrotomy is a life-saving procedure that is seldom performed by anesthesiologists. Anesthesiology residents are traditionally trained to perform cricothyrotomy with artificial mannequins and exposed larynx models from animals. These models lack the tissue feel of performing a cricothyrotomy on a patient with difficult neck anatomy. To improve the training experience, we developed a novel training model for cricothyrotomy using a porcine larynx, which incorporates ultrasonographic examination to identify the cricothyroid membrane, and permits varying degrees of difficulty. METHODS: Twenty-five residents were enrolled in a training curriculum consisting of (1) preprocedure training modules, (2) preprocedure hands-on demonstrations, and (3) three separate cricothyrotomy procedures using a porcine trachea. The first two procedures consisted of residents performing an open and a percutaneous cricothyrotomy on a model, which consisted of porcine trachea with chicken skin pinned over the larynx. The third procedure involved performing an open cricothyrotomy on a more challenging model, constructed by placing several layers of bacon fat between the larynx and chicken skin, making digital palpation of the laryngeal landmarks impossible. Before performing the procedure, residents located the cricothyroid interval with ultrasound. A postcurriculum survey was administered. RESULTS: Twenty-three of 25 residents were able to perform the open cricothyrotomy by digital palpation on the airway model on the first attempt. With the more challenging model, all 25 residents were able to locate the cricothyroid membrane by ultrasound and successfully perform open and percutaneous cricothyrotomy. Participants felt that they learned new information regarding ultrasound identification of laryngeal anatomy and gained valuable procedural experience in this training exercise. CONCLUSIONS: Use of the porcine trachea with overlying animal skin and fat provides an effective partial-task trainer for open and percutaneous surgical airway education and lends itself to integration of ultrasound imaging for real-time identification of laryngeal and tracheal anatomy.