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Purpose: We have focused on the two-dimensional (B-mode) and the time-motion (M-mode) analysis of the zone of apposition to determine the reliability of diaphragm ultrasonography in the clinical environment., Methods: Ten healthy volunteers were enrolled and studied by three operators with different skills in ultrasonography. For every volunteer, each operator acquired three images of the diaphragm for each side, both in B-mode and in M-mode. Then a fourth operator calculated the thickening fraction (TF), by means of the formula TF = (TEI - TEE)/TEE (TEI is the thickness at end inspiration and TEE the thickness at end expiration). Afterwards, intraclass correlation coefficients (ICCs) were computed on TF to establish reproducibility and repeatability both in the B- and M-modes. A Coefficient of Repeatability or repeatability (CR) ≤ 0.3 was considered acceptable., Results: Both B-mode (CRs 0.16-0.26) and M-mode (CRs 0.10-0.15) were sufficiently repeatable to assess TF, except for the less experienced operator (CRs B-Mode 0.20-0.32). Reproducibility was moderate to good between operators with CRs much narrower for the M-Mode (0.13-0.14)., Conclusions: The results of our study have shown that diaphragm ultrasound is repeatable and reproducible when carried out by a radiologist or an intensivist with a basic curriculum in ultrasonography. The method is more accurate when using the M-mode for less experienced operators, and in this case, repeatability and reproducibility are not sufficient to make clinical decisions. No TF value lower than 36% was obtained using both techniques. This suggests the existence of a cut-off value that could be used as an initial tool to discriminate healthy subjects from those affected by diaphragmatic dysfunction., Clinical Trial Registration: EUDRACT 2015-004635-12., (© 2020. Società Italiana di Ultrasonologia in Medicina e Biologia (SIUMB).)

Background: The extensive use of neuromuscular blocking agents (NMBAs) during surgical procedures still leads to potential residual paralyzing effects in the postoperative period. Indeed, neuromuscular monitoring in an intra-operative setting is strongly advocated. Acetylcholinesterase inhibitors can reverse muscle block, but their short half-life may lead to residual curarization in the ward, especially when intermediate or long-acting NMBAs have been administered. Sugammadex is the first selective reversal drug for steroidal NMBAs; it has been shown to give full and rapid recovery of muscle strength, thus minimizing the occurrence of residual curarization. Acceleromyography of the adductor pollicis is the gold standard for detecting residual curarization, but it cannot be carried out on conscious patients. Ultrasonography of diaphragm thickness may reveal residual effects of NMBAs in conscious patients., Methods/design: This prospective, double-blind, single-center randomized controlled study will enroll patients (of American Society of Anesthesiologists physical status I-II, aged 18-80 years) who will be scheduled to undergo deep neuromuscular block with rocuronium for ear, nose, or throat surgery. The study's primary objective will be to compare the effects of neostigmine and sugammadex on postoperative residual curarization using two different tools: diaphragm ultrasonography and acceleromyography of the adductor pollicis. Patients will be extubated when the train-of-four ratio is > 0.9. Diaphragm ultrasonography will be used to evaluate the thickening fraction, which is the difference between the end expiratory thickness and the end inspiratory thickness, normalized to the end expiratory thickness. Ultrasonography will be performed before the initiation of general anesthesia, before extubation, and 10 and 30 min after discharging patients from the operating room. The secondary objective will be to compare the incidence of postoperative complications due to residual neuromuscular block between patients who receive neostigmine and those who receive sugammadex., Discussion: Postoperative residual curarization is a topic of paramount importance, because its occurrence can cause complications and increase the length of stay in hospital and the related costs. Diaphragm ultrasound assessment may become a bedside integrative tool in the neuromuscular monitoring field to detect concealed residual curarization in surgical patients who have received paralyzing agents., Trial Registration: EudraCT, 2013-004787-62. Registered on 18 June 2014, as "Evaluation of muscle function recovery after deep neuromuscular blockade by acceleromyography of the adductor pollicis or diaphragmatic echography: comparison between sugammadex and neostigmine." ClinicalTrials.gov, NCT02698969 . Registered on 15 February 2016, as "Recovery of Muscle Function After Deep Neuromuscular Block by Means of Diaphragm Ultrasonography and Adductor Pollicis Acceleromyography: Comparison of Neostigmine vs. Sugammadex as Reversal Drugs."