Construct Validity of Simulation Model for Training the Ultrasound-Guided Nerve Block and Catheter Placement

Background: Continuous ultrasound-guided peripheral nerve block is a widely practiced technique that can be a challenge for young anesthesiologists. We developed a new simulation model for learning perineural catheter placement. This study aims to test the validity of the model and investigate the learning process of residents on this model. Methods: The simulation model was constructed with partial animal tissue and physical materials. Ultrasound-guided simulation of perineural catheter placement was then performed. Twenty-eight anesthesiologists representing novices, intermediates and experts were required to perform 30 trials within one single day. Practice trials were video-recorded to extract data of task time and performance errors. Construct validity were assessed. Results: Practicing on the simulation model, experts were able to achieve superior task performance, i.e., shorter task time (P < 0.001) and fewer performance errors (P < 0.001), than intermediates and novices. Learning curve recorded from young residents suggested that they were not able to reach the proficiency level as experts within one training day. Conclusions: This hybrid simulation model was capable of training the skills required for continuous ultrasound-guided peripheral nerve block. Future studies under this model need to concern extending the duration of the training phase for residents.

EFFECTIVENESS OF INTRAOPERATIVE PLACEMENT OF A PERINEURAL NERVE CATHETER IN PATIENT ROAD TO RECOVERY

Post surgical pain after major lower limb amputation is a major problem to the patients recovery. The majority of patients require continuous opioid analgesics and NSAIDs after surgery, which are associated with side-effects. In order to overcome the pain encountered by these patients, we routinely practice intraoperative placement of aNerve catheter along the peripheral nerve stump. The anesthetic medication is used to calm the nerves and overcome pain perceived by the patient. We study the effectiveness of pain control and reduction in the need for oral / parenteral administration of analgesics. This step could potentially reduce post-procedure analgesics usage and other related adverse effects. Methods: A retrospective study and data review of 98 patients who had major lower limb amputation for peripheral vascular disease over a 5-year duration. Intra-operatively, 42 patients had a perineural catheter placement were compared to 56 patients who had oral and parenteral analgesics prescribed to treat post operative pain. The primary outcomes of this studywere the number and quantity of drug needed in the first 4 days postoperatively and swiftness in postoperative recovery to do rehabilitation. Results: 98 major lower-limb amputations were selected. Analysis shows that perineural catheter use was associated with a decreased need for postoperative analgesics and decreased postoperative pain scores at 72 hours. Perineural catheter use led to a 65% reduction inopioid + NSAIDs use during the early postoperative period. Data also suggests the patient tend to fair better in rehabilitation work with nerve catheter placement. Conclusions: Post operative continuous infusions of local anesthetic through nerve catheter are safe and effective in reducing pain post-amputation. The analgesic medications requirement after major lower limb amputation can be significantly lowered so are the complications.

Bone stump formation against the background of post-amputation pain syndrome

Introduction: Bone is the basis of the stump. Aim: To study the impact of post-amputation pain syndrome on the nature of reparative processes in the bone residual limb. Material and methods: Three series of experiments were performed on 45 rabbits, 15 in each with mid-third thigh amputation and muscular plasty. In series 1, 2, a perineural catheter was attached to the sciatic nerve stump during amputation, and mechanical irritation of the nerve was performed daily for 20 minutes in series 1 for 20 days. In series 2, 0.3 mL of lidocaine (1%) was injected through the catheter into the circumference of the nerve twice daily for 20 days. Series 3 is a control. The follow-up periods were 1, 3, 6 months. The study method was histological with infusion of the vessels with ink-gelatin mixture. Results and discussion: In series 1, there was a sharp disturbance of the reparative process, which consisted in shape changes, resorption of the cortical diaphyseal plate, fractures, stump deformity, absence of bone closure plate formation, and microcirculatory disturbances. In the overall majority of experiments of series 2, the stumps retained the shape and structure characteristic of diaphysis with normalization of microcirculation. In series 3, the results of the residual limb formation were better than in series1, but worse than in series 2. Conclusions: When the pain syndrome is resolved within 20 days after amputation, a bone stump is formed with an organotypic shape and structure characteristic of the diaphysis, the formation of a compact closure plate of mature bone tissue, normalization of the medullary tissues and blood circulation. In post-amputation pain syndrome, organotypic formation of the residual limb does not occur.

Decreasing the leakage of continuous femoral nerve catheter fixation using 2 - octyl cyanoacrylate glue ( Demabond® ): A Randomized Controlled Trial study

Background : Continuous peripheral nerve catheters (CPNCs) have been used for postoperative pain relief. The common problem with CPNCs is pericatheter leakage that can compromise the sterile dressing, un-necessitating frequent dressing that may increase the risk of dislodgement and perineural catheter colonization or infections. Adhesive glue is useful for fixing peripheral nerve catheter as well as prevent leakage around the puncture site. This study aimed to evaluate the incidence of pericatheter leakage by using fixation with 2 -octyl cyanoacrylate glue (Demabond) compared to sterile strip. Methods : Thirty patients undergoing unilateral total knee arthroplasty and received continuous femoral nerve block were randomized to perineural catheter fixation with 2-octyl cyanoacrylate glue or sterile strip. The primary outcome was the incidence of pericatheter leakage. Secondary outcomes included frequent of catheter migration, difficulty of catheter removal, pain score and patient satisfaction. Results : The incidence of pericatheter leakage at 48 hours was 0% versus 100% in the intervention and control group. The incidence of displacement at 24 and 48 hours was 6.7% versus 93.3% and 6.7% versus 100%, respectively (P < 0.001). There was no difference in numeric rating scale, difficulty of catheter removal as well as satisfaction scores between groups. Conclusion : Catheter fixation with 2-octylcyanoacrylate reduced the incidence of pericatheter leakage as well as catheter displacement over 48 hours compare to sterile strip.