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Neuromuscular Monitoring (neuromuscular + monitoring)

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Medical Sciences	100%

Selected Abstracts

Acceleromyography and mechanomyography for establishing potency of neuromuscular blocking agents: a randomized-controlled trial

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 4 2009
C. CLAUDIUS
Background: Acceleromyography (AMG) is increasingly being used in neuromuscular research, including in studies establishing the potency of neuromuscular blocking and reversal agents. However, AMG is insufficiently validated for use interchangeably with the gold standard, mechanomyography (MMG) for this purpose. The aim of this study was to compare AMG and MMG for establishing dose,response relationship and potency, using rocuronium as an example. Methods: We included 40 adult patients in this randomized-controlled single-dose response study. Anaesthesia was induced and maintained with propofol and opioid. Neuromuscular blockade was induced with rocuronium 100, 150, 200 or 250 ,g/kg. Neuromuscular monitoring was performed with AMG (TOF-Watch® SX) with pre-load (Hand Adapter) at one arm and MMG (modified TOF-Watch® SX) on the other, using 0.1 Hz single twitch stimulation. Dose,response relationships were determined for both recording methods using log (dose) against probit (maximum block). The obtained slopes of the regression lines, ED50, ED95 and the maximum block were compared. Results: The ED50 and ED95 [95% confidence interval (CI)] for AMG were 185 ,g/kg (167,205 ,g/kg) and 368 ,g/kg (288,470 ,g/kg), compared with 174 ,g/kg (159,191 ,g/kg) and 338 ,g/kg (273,418 ,g/kg) for MMG. There were no statistically significant biases in maximum block, ED50, ED95 or slopes obtained with the two methods. Conclusion: Our results indicate that any possible difference between AMG and MMG is so small that it justifies AMG to be used for establishing the potency of neuromuscular blocking agents. However, the wide CIs show that we cannot rule out a 13% higher ED50 and a 26% higher ED95 for AMG. [source]

Probability of acceptable intubation conditions with low dose rocuronium during light sevoflurane anaesthesia in children

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 8 2001
M. Eikermann
Background: To define the rocuronium doses which would provide 50%, 90%, and 95% probability of ,acceptable' intubation conditions during light sevoflurane anaesthesia, we studied 60 children aged 2,7 years in a prospective, randomised, assessor blinded study. Methods: After mask ventilation with 1 MAC sevoflurane/N2O for 17±1 (x̌±SD) min we administered rocuronium (either 0.15, 0.22, 0.3, 0.5, or 1.0 mg ,· ,kg,1) or placebo, and quantified the evoked force of the adductor pollicis muscle. Intubation conditions were assessed before and 2 min after injection of the test drug. Results: Intubation conditions were improved significantly with rocuronium and scored ,acceptable' in 70%, 90%, and 100% of the children after injection of rocuronium 0.15, 0.22, and 0.3 mg ,· ,kg,1, respectively. In parallel, twitch tension decreased to 53% (6,100), 26% (11,100), and 11% (0,19) of baseline (median (range)). Recovery of train-of-four ratio to 0.8 was achieved 13 (7,19), 16 (8,28), and 27 (23,44) min after injection of the respective rocuronium doses. Higher rocuronium doses did not further improve intubation conditions but only prolonged time of neuromuscular recovery. Logistic regression analysis revealed that rocuronium 0.11 (CI 0.05,0.16), 0.21 (0.14,0.28), and 0.25 (0.15,0.34) mg ,· ,kg,1 provides a 50%, 90%, and 95% probability of ,acceptable' intubation conditions in children during 1 MAC sevoflurane/N2O anaesthesia, respectively. Furthermore, we calculated that force depression of adductor pollicis muscle to 81% (CI 72,90), 58% (42,74), and 50% (29,71) of baseline is associated with 50%, 90%, and 95% probability of ,acceptable' intubation conditions. Conclusions: Submaximal depression of muscle force with low dose rocuronium improves intubation conditions in children during light sevoflurane anaesthesia while allowing rapid recovery of neuromuscular function. However, when using low dose rocuronium neuromuscular monitoring may be helpful to detect children with inadequate response to the relaxant so as to avoid an unsuccessful intubation attempt. [source]

The use of sugammadex in a patient with myasthenia gravis

ANAESTHESIA, Issue 3 2010
C. Unterbuchner
Summary Myasthenia gravis, affecting neuromuscular transmission, leads to a large variability in sensitivity to depolarising and non-depolarising neuromuscular blocking drugs. We report the successful use of the modified ,-cyclodextrin sugammadex in a myasthenic patient to reverse a rocuronium-induced deep level of neuromuscular block. After spontaneous neuromuscular recovery of T2 (second twitch of the train-of-four series), we administered 2 mg.kg,1 of sugammadex intravenously, reversing neuromuscular blockade to a train-of-four ratio (T4/T1) > 90% within 210 s. Sugammadex, in combination with objective neuromuscular monitoring, can be used to reverse rocuronium-induced neuromuscular blockade in patients with myasthenia gravis, thereby avoiding the need for reversal with acetylcholinesterase inhibitors. [source]

Antagonism of non-depolarising neuromuscular block: current practice

ANAESTHESIA, Issue 2009
A. F. Kopman
Summary There is now mounting evidence that even small degrees of postoperative residual neuromuscular block increases the incidence of adverse respiratory events in the Post Anaesthesia Care Unit and may increase longer-term morbidity as well. In the absence of quantitative neuromuscular monitoring, residual block is easily missed. A very strong case can be made for the routine administration of a non-depolarising antagonist unless it can be objectively demonstrated that complete recovery has occurred spontaneously. However, the use of acetylcholinesterase inhibitors is associated with the potential for cardiovascular and respiratory side-effects, so there are cogent reasons for using low doses when the level of neuromuscular block is not intense. As little as 0.015,0.025 mg.kg,1 of neostigmine is required at a train-of-four count of four with minimal fade, whereas 0.04,0.05 mg.kg,1 is needed at a train-of-four count of two or three. If only a single twitch or none at all can be evoked, neostigmine should not be expected to promptly reverse neuromuscular block, and antagonism is best delayed till a train-of-four-count of two is achieved. [source]

Cyclodextrins and the emergence of sugammadex

ANAESTHESIA, Issue 2009
L. H. D. J. Booij
Summary Residual paralysis, with its subsequent postoperative pulmonary sequelae, is one of the major complications of anaesthesia, and was recognised shortly after the introduction of neuromuscular blocking drugs into routine clinical practice. Although its incidence decreased with the introduction of intermediate duration drugs, and further diminished with routine neuromuscular monitoring and reversal with cholinesterase inhibitors, residual paralysis still remained a problem. In the search for alternatives to stop the effect of neuromuscular blocking drugs and to match their duration of action to clinical need, chelation of the non-depolarising neuromuscular blocking drugs was considered. It was recognised that cyclodextrins could encapsulate steroidal molecules and thereby inactivate the aminosteroidal neuromuscular blocking drugs. In order to improve the binding of rocuronium to the cyclodextrin and to increase the compound's water solubility, the molecule was modified. This led to the development of sugammadex (Org 25969), a modified ,-cyclodextrin. The modification of the molecule and the initial in vitro studies that led to in vivo and later human studies of this conceptually new drug for anaesthesia are described. [source]

Monitoring neuromuscular block: an update

ANAESTHESIA, Issue 2009
T. Fuchs-Buder
Summary The first part of this article presents an update of the basic considerations of neuromuscular monitoring. It emphasises the need to assure supramaximal stimulation, to place the stimulating electrodes correctly and to use appropriate sites for nerve stimulation as well as appropriate stimulation patterns. The second part focuses on current developments and ongoing discussion. The authors describe the performance of acceleromyography and the need for initial calibration when using these quantitative devices. [source]