OBJECTIVE: Phase 1: to determine the feasibility of desensitizing ventral branches of spinal nerves within the rectus sheath using an ultrasound-guided rectus sheath block (USRSB). Phase 2: to determine the effect of preoperative USRSB on intraoperative responses to surgical stimulation and postoperative pain.
METHODS: Cadaveric study and prospective, randomized, blinded, parallel-arm clinical trial.
METHODS: A group of five cat cadavers and 37 shelter-owned cats undergoing ovariohysterectomy.
METHODS: Phase 1: anatomical dissection was performed on one uninjected cadaver. Abdominal walls were dissected in four cadavers (eight hemiabdomens) following bilateral USRSB using 1:1 new methylene blue and 0.5% bupivacaine (0.8 mL kg-1 total). Phase 2: preoperative bilateral USRSB was performed with 0.8 mL kg-1 of 0.25% bupivacaine (RSB) or equivalent volume of 0.9% saline (CONTROL). Intraoperative systolic arterial blood pressure (SAP), heart rate (HR), respiratory rate (fR) and vaporizer setting (vap%) were recorded before skin incision, during celiotomy and abdominal wall closure. In recovery, cats were administered robenacoxib (2 mg kg-1; CONTROL) or 0.9% saline (0.1 mL kg-1; RSB) subcutaneously. Postoperative pain was evaluated for 6 hours using the Glasgow Composite Measure Pain Scale.
RESULTS: Phase 1: spinal nerves T9-L3 were identified within the rectus sheath, and stained in 0%, 40%, 63%, 75%, 100%, 88%, 50% and 13% of hemiabdomens, respectively. Phase 2: 37 cats were included (RSB, n = 17; CONTROL, n = 20). Intraoperatively, SAP, HR and fR were not significantly different between groups. Vap% was significantly lower in RSB during celiotomy (p = 0.036) and closure (p = 0.044). Postoperatively, RSB cats were 5.3 times (95% CI 1.8-8.3) more likely to require rescue analgesia than CONTROL cats.
CONCLUSIONS: During surgery, USRSB with bupivacaine offered minor benefits and provided markedly less postoperative analgesia than robenacoxib, indicating that relying on USRSB provides insufficient postoperative analgesia for ovariohysterectomy in cats.

Modified thoracoabdominal nerve block through the perichondrial approach (M-TAPA) is a novel strategy for peripheral nerve block in the abdomen. Its usefulness has been highlighted in adults, but no literature is currently available regarding its efficacy in infants. This report describes the cases of a one-day-old neonate in open abdominal surgery and a one-month-old infant in laparoscopic surgery who received M-TAPA. The postoperative condition of the infants was assessed through a neonate pain scale and the Face, Legs, Activity, Cry, and Consolability behavioral scale, respectively; both scales remained at 0 until discharge. Despite the need for special attention, M-TAPA may provide effective analgesia in neonatal and infant abdominal surgery in addition to adult cases, and its indications should be considered.

OBJECTIVE: Simulation-based education in ultrasound-guided regional anesthesia (UGRA) improves knowledge, skills, and patient outcomes. Nevertheless, it is not known how simulation-based UGRA education is used across Canada. We aimed to characterize the current use of simulation-based UGRA education in Canadian anesthesiology residency training programs.
METHODS: We developed and distributed a structured national survey to simulation leads of all 17 Canadian anesthesiology residency training programs. The survey inquired about program demographics, simulation modalities, facilitators and barriers to simulation use, use for assessment, and beliefs around simulation-based UGRA education. We gathered data from August to November 2023 and summarized our findings descriptively.
RESULTS: Fifteen programs (88%) responded to our survey. Eight programs (53%) used UGRA simulation for technical training and nine programs (60%) for nontechnical training. The most common simulators used were live model scanning (13 programs, 87%) and gel phantom models (7 programs, 47%). Five programs (33%) mandated simulation-based UGRA in their curriculum. We found that deliberate practice and improved patient safety were most valued in simulation training while lack of funding and faculty availability were the most common barriers to implementation. Most respondents agreed that formative simulation-based education would improve trainee skills and called for greater standardization. Nevertheless, there were mixed responses regarding summative UGRA simulation and the need for simulation proficiency before clinical practice.
CONCLUSIONS: Our findings show significant variations in simulation implementation and views on UGRA simulation-based education among Canadian anesthesiology residency training programs. Future studies should explore avenues to overcome barriers and improve knowledge translation in UGRA.
RéSUMé: OBJECTIF: La formation basée sur la simulation en anesthésie régionale échoguidée améliore les connaissances, les compétences et les issues pour les patient·es. Néanmoins, on ne sait pas comment la formation en AR échoguidée basée sur la simulation est utilisée au Canada. Nous avons cherché à caractériser l’utilisation actuelle de l’enseignement de l’AR échoguidée basée sur la simulation dans les programmes canadiens de résidence en anesthésiologie. MéTHODE: Nous avons élaboré et distribué un sondage national structuré aux responsables de la simulation des 17 programmes canadiens de résidence en anesthésiologie. L’enquête portait sur les données démographiques du programme, les modalités de simulation, les facilitateurs et les obstacles à l’utilisation de la simulation, son utilisation pour l’évaluation, et les croyances concernant l’éducation en AR échoguidée basée sur la simulation. Nous avons recueilli des données d’août à novembre 2023 et résumé nos résultats de manière descriptive. RéSULTATS: Quinze programmes (88 %) ont répondu à notre sondage. Huit programmes (53 %) utilisent la simulation en AR échoguidée pour la formation technique et neuf programmes (60 %) pour la formation non technique. Les simulateurs les plus couramment utilisés étaient le balayage sur modèles vivants (13 programmes, 87 %) et les modèles de fantômes en gel (7 programmes, 47 %). Cinq programmes (33 %) ont rendu obligatoire l’AR échoguidée basée sur la simulation dans leur programme. Nous avons constaté que la pratique délibérée et l’amélioration de la sécurité des patient·es étaient les plus appréciées dans la formation par simulation, tandis que le manque de financement et la disponibilité du corps professoral étaient les obstacles les plus courants à la mise en œuvre. La plupart des répondant·es ont convenu que l’éducation formative basée sur la simulation améliorerait les compétences des stagiaires et ont appelé à une plus grande standardisation. Néanmoins, les réponses étaient mitigées concernant la simulation sommative en AR échoguidée et la nécessité d’une maîtrise de la simulation avant la pratique clinique. CONCLUSION: Nos résultats montrent des variations significatives dans la mise en œuvre de la simulation et les points de vue sur l’éducation basée sur la simulation en AR échoguidée parmi les programmes canadiens de résidence en anesthésiologie. Les études futures devraient explorer les moyens de surmonter les obstacles et d’améliorer l’application des connaissances à l’anesthésie régionale échoguidée.

OBJECTIVE: To evaluate the in vivo spread of iodinated contrast following injections in the transversus abdominis plane (TAP) and rectus sheath in anesthetized dogs via computed tomography. Secondarily, the time of performing each block was compared.
METHODS: 6 adult, purpose-bred Beagles.
METHODS: In a prospective crossover study, dogs were administered injections either in the rectus sheath or transversus abdominis fascial plane in the same manner as a rectus sheath block (RSB) or TAP block using dilute iodinated contrast. Computed tomography scans were performed immediately following injection (time [T]-0) and at 3, 9, 18, and 30 minutes postinjection. Data regarding the spread in the cranial-caudal and lateral directions and time to perform the injections were compared between the 2 techniques using paired or 2-sample t tests.
RESULTS: There was significantly greater spread in the cranial-caudal direction in the RSB group (62.9 ± 6.4 mm vs 54.8 ± 6.8 mm at T30; P = .009), whereas spread in the lateral direction was greater in the TAP group (37.3 ± 3.0 mm vs 48.6 ± 6.1 mm at T30; P < .0001). The RSB injection was performed in a more time-efficient manner than TAP injection (48.2 ± 3.2 seconds vs 82.3 ± 8.7 seconds; P = .03).
CONCLUSIONS: In living subjects, RSB injections resulted in greater cranial-caudal spread while TAP injections resulted in greater lateral spread. Rectus sheath block injections were performed in a more time efficient manner compared to a single point TAP injection in anesthetized dogs.
CONCLUSIONS: The RSB was performed in a more time-efficient manner and would likely result in greater coverage of the ventral midline. The TAP block would likely result in more significant regional anesthetic coverage of the lateral abdominal wall. Further studies are required to determine the degree of the clinical significance of these results.

UNASSIGNED: Simulation is increasingly used in medical teaching. Various studies have evaluated different simulation models for training of regional anesthesia (RA). We compared the use of human cadaver and blue phantom models for training of regional anesthesia to novice postgraduate students of anesthesiology.
UNASSIGNED: Fifty students were taught knobology of the ultrasonography (USG) machine. They were divided into two equal groups by computer-generated random number table, and the groups assigned were kept in sealed envelopes. In group BP, students were trained on a blue phantom model, and in group HC, students were trained on human cadaver. After training, a didactic video of sonoanatomy of the supraclavicular block was shown to all participants. The block performance was then judged on patients requiring supraclavicular block. The primary objective of the study was to compare the block performance time, and secondary objectives were the quality of image acquired, orientation of transducer to the target, identification of ultrasound artifacts, errors committed, complications, and success rate.
UNASSIGNED: The mean block performance time was shorter in group HC compared to group BP (451.96 ± 50.25 and 526.48 ± 43.486 s, respectively; P < 0.001). The image quality score, transducer orientation to the target, and identification of USG artifacts were better in group HC compared to group BP, with lesser number of needle passes.
UNASSIGNED: Cadaver-based training produced better results compared to blue phantom simulator model for teaching of ultrasound-guided RA to novice postgraduate trainees of anesthesiology.

Interscalene nerve block (ISB) is an effective and low-risk local anesthetic (LA) procedure that is commonly employed for shoulder surgery. While phrenic nerve involvement occurs to some degree in every ISB procedure, the incidence of hypoxemia and other clinical signs of diaphragmatic disruption is much lower. This is a case of a 36-year-old female with no underlying respiratory disease who developed hypoxemia requiring a night of observation following an ISB for a rotator cuff repair procedure in an ambulatory surgical center. Her hypoxemia was easily treated with supplemental oxygen and she made a full recovery by the next day. The use of ultrasound guidance, reduced LA volume, less potent medication, sterile fluid for optimal visualization, and extrafascial administration should be considered for all patients receiving an ISB to prevent respiratory complications.

Methods to remove retained peripheral nerve catheters range from non-invasive techniques to open surgical procedures. This study reviews two cases requiring surgical intervention for catheter remnant removal after catheter breakage and presents a systematic review describing the diagnosis and treatment of retained perineural catheters. While still very rare, our case report and systematic review demonstrate that retained nerve catheters can occur as the result of kinking or knotting, but also from catheter breakage. We recommend risk mitigation strategies for providers placing or caring for patients with regional nerve catheters.

Breast cancer is unfortunately the most common cancer in women, although survival rates have greatly increased in recent years. Breast surgery can be very aggressive and therefore highly painful, leading to high rates of acute postsurgical pain and chronic pain. In addition to general anesthesia (GA), ultrasound-guided regional anesthesia (RA) is sometimes performed to help reduce acute postoperative pain and consumption of opioids. Although effective, the main limitation of fascial plane blocks is that they require high volumes of local anesthetics, carrying the risk of local anesthetic systemic toxicity. In this article, we present the case of a 41-year-old woman, who refused GA and was successfully operated on for bilateral breast cancer, under a spontaneous breathing opioid-free sedation and ultrasound-guided RA, based on only 0.2% levobupivacaine with the addition of dexamethasone and dexmedetomidine as adjuvants. Despite this, postoperative analgesia lasted for more than 48 hours, and the patient did not require additional analgesia or opioids.

Postoperative pain after surgical clavicle fixation is difficult to treat and often responds incompletely to opioid analgesics. Unfavorable side effects and the risk of misuse of opioid analgesics make regional anesthetic techniques an attractive strategy for treating clavicular pain. Literature on continuous nerve blocks with catheter placement for more prolonged pain control for clavicle fractures is scarce, while such techniques are common for other shoulder surgeries. This case report presents a successful continuous interscalene brachial plexus block (ISB) after surgical fixation of a midshaft clavicle fracture. The patient was discharged home on the day of the operation with a portable pump, which provided a local anesthetic infusion for five days postoperatively. The patient was very satisfied with her pain control and only required one dose of oral opioid analgesic postoperatively.

Needle visualization is essential to avoid vascular puncture and nerve injury in ultrasound-guided regional anesthesia. Several factors that statistically influence needle visibility have been described but the dimensions of their individual impact remain unclear. This study aimed to quantify the impact of various independent factors on ultrasound needle visibility.
A total of 1500 ultrasound videos of in-plane needle insertions were obtained in embalmed cadavers with ten different commercially available echogenic and non-echogenic needles at different insertion angles and bevel orientations in a full factorial study design. The visibility of needle tip and shaft were rated as \"good\" or \"poor\" visibility. Nominal logistic regression analyses were calculated for the visibility of the needle tip and shaft.
SonoPlex Stim Sprotte, SonoTAP Facet (needle tip and shaft) and Spinostar PencilPoint (needle tip)), insertion angle and bevel orientation were associated with good ultrasound visibility, reaching statistical significance (p < 0.05). The range of the effect on the log-odds scale for needle tip visibility was largest for the insertion angle with 6.33, followed by the tissue condition (3.76), bevel orientation (1.45) and the needle types (1.25). Regarding the needle shaft visibility, the largest effect range was observed with the insertion angle (7.36), followed by the tissue conditions with 3.96, needle type (1.86) and bevel orientation (0.95).
In-plane needle visibility in ultrasound images depends mainly on the insertion angle, as expected. This is closely followed by the tissue condition, which is a factor related to the patient, thus cannot be altered to improve needle visibility. In the dimensions of the log-odds scale, the choice of a specific needle is far less important towards achieving a good visualization, whereas optimizing the bevel orientation can have a larger impact than the needle choice. Concluding from the relative dimensions of factors that determine needle visibility in this model, the importance of needles with echogenic features may be overrated.