Citations

ABSTRACTIntroduction/AimsNeuromuscular ultrasound (NMUS), initially performed by physicians, is increasingly performed by technicians in many electrodiagnostic (EDX) laboratories for certain studies under physician supervision. The aims of this study were to determine: (1) the reproducibility of nonphysician sonographers' assessments of the median nerve and (2) the need for ongoing training to maintain the reproducibility and reliability of median nerve ultrasound assessments.MethodsThe median nerve was examined sonographically in a healthy volunteer by 12 nonphysicians on 3 separate occasions: Day 1 and then 2 weeks (Day 2) and 4 months (Day 3) later. Cross‐sectional area (CSA) and wrist‐to‐forearm ratios (WFRs) were calculated each time. Sonographers were retrained prior to Day 2. Reproducibility and reliability were determined using coefficients of variation calculated for each characteristic for each day and each nonphysician sonographer, comparing performance across the 3 time points.ResultsThere was overall less variation for each characteristic (wrist CSA, forearm CSA, and WFR) on Day 2 compared to Day 1 (coefficients of variation 3.0%, 5.4%, and 5.7% vs. 8.8%, 15.5%, and 11.3%, respectively), both when viewed at the group and individual levels, indicating an improvement in reproducibility and reliability after the retraining session. The improvement was similar for Day 3.DiscussionThis study demonstrates the need for training and subsequent retraining sessions to ensure the reproducibility and reliability of NMUS measurements in the median nerve.

Abstract Introduction/Aims Point‐of‐care ultrasound of the diaphragm is highly sensitive and specific in the detection of neuromuscular diaphragmatic dysfunction. In some patients with neuromuscular diaphragmatic dysfunction, paradoxical thinning of the diaphragm during inspiration is observed on ultrasound; however, its frequency, electrodiagnostic associations, and prognostic significance remain uncertain. Methods Medical records of patients presenting to two electrodiagnostic laboratories (Mayo Clinic, Rochester, Minnesota and University of Alberta, Edmonton, Alberta) from January 1, 2022 to December 31, 2022, for evaluation of suspected neuromuscular respiratory failure, were reviewed. Results 214 patients were referred and 19 patients excluded due to incomplete information. Of 195 patients (384 hemidiaphragms), 104 had phrenic neuropathy, 12 had myopathy, and 79 had no evidence of neuromuscular disease affecting the diaphragm. Paradoxical thinning occurred in 31 (27%) patients with neuromuscular diaphragmatic dysfunction and was unilateral in 30, the majority (83%) having normal contralateral ultrasound. Phrenic nerve conduction studies and diaphragm electromyography results did not distinguish patients with paradoxical thinning versus without. Most patients (71%) with paradoxical thinning required non‐invasive ventilation (NIV), including 16 with unilateral paradoxical thinning. Paradoxical thinning and BMI ≥30 kg/m 2 were risk factors for requiring NIV in multivariable logistic regression analysis, with odds ratios of 2.887 (95% CI:1.166, 7.151) and 2.561 (95% CI: 1.186, 5.532), respectively. Discussion Paradoxical thinning of the diaphragm occurs in patients with prominent neuromuscular diaphragmatic dysfunction, most commonly from phrenic neuropathy, and is a significant risk factor for requiring NIV. Unilateral paradoxical thinning is sufficient for needing NIV. BMI ≥30 kg/m 2 additionally increases risk of requiring NIV in patients with neuromuscular diaphragmatic dysfunction.