The Relaxometer: A complete and comprehensive computer-controlled neuromuscular transmission measurement system developed for clinical research on muscle relaxants

Rowaan, Cornelis; Vandenbrom, R. H. G.; Wierda, J. M. K. H.

doi:10.1007/bf01627635

Cited by 40 publications

(20 citation statements)

References 23 publications

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“…Recordings of the single twitch contractions of the adductor pollicis muscle were obtained by stimulating the ulnar nerve at the wrist using surface electrodes with supramaximal squarewave stimuli of 0.2 msec duration at a frequency of 0.1 Hz. The resultant force of thumb adduction was quantified via a force displacement transducer after applying a resting tension of 200 -400 g and recorded via a Relaxometer 2 6 and calculated using a closed loop infusion computer program with an algorithm included. The closed-loop control system is based on a fuzzy logic system and consists of 32 fuzzy rules inferencing over three inputs (error, relaxation rate of change, relaxation stability).…”

Section: Methodsmentioning

confidence: 99%

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Smoking does not alter the dose-requirements and the pharmacodynamics of rocuronium

Pühringer

Keller

Löckinger

et al. 2000

Can J Anesth/J Can Anesth

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Purpose: Controversial data about the effect of smoking on the dose-requirements and the pharamcodynamics of rocuronium have been reported recently. This study was conducted to evaluate the dose-requirements and the pharmacodynamics of rocuronium in smokers using target controlled infusion. Methods:The dose-requirements of rocuronium for 60 min relaxation, using target controlled infusion, given under intravenous anaesthesia with propofol, fentanyl and nitrous oxide was studied in 37 smokers and 37 nonsmokers. Initially 450 µg·kg -1 rocuronium were administered, neuromuscular effects were quantified by recording the single twitch response of the adductor pollicis muscle after ulnar nerve stimulation using a force transducer, and the neuromuscular block was kept at 80% by target controlled infusion throughout the procedure.Results: The dose-requirements for one hour relaxation were 867 ± 116 µg·kg -1 ·hr -1 for smokers (S) and 839 ± 149 µg·kg -1 ·hr -1 for non-smokers (NS). The duration to 10% and the spontaneous recovery from 25% to 75% of the control twitch response also showed no differences between S (17.2 ± 3.4 min, 10.6 ± 0.9 min ) and NS (18.9 ± 4.3 min, 10.9 ± 3.2 min), as well as maximum block, onset time and infusion rate. Conclusion:Smoking does not alter the dose-requirements for rocuronium and no effects on the onset time, degree of block, time to maximum block, duration 10% and spontaneous recovery index were observed.Objectif : Des données controversées au sujet de l'effet du tabagisme sur les doses nécessaires de rocuronium et sur sa pharmacodynamie ont été publiées récemment. La présente étude a été menée pour évaluer les doses efficaces de rocuronium et sa pharmacodynamie chez des fumeurs en utilisant une perfusion cible contrôlée.Méthode : Les doses de rocuronium nécessaires pour provoquer un relâchement musculaire de 60 min ont été étudiées chez 37 fumeurs et 37 non fumeurs, à l'aide d'une perfusion cible contrôlée. Elles ont été administrées sous anesthésie intraveineuse avec du propofol, du fentanyl et du protoxyde d'azote. On a d'abord administré 450 µg·kg -1 de rocuronium, puis on a quantifié les effets neuromusculaires en enregistrant les contractions uniques de l'adducteur du pouce après la stimulation du nerf cubital à l'aide d'un transducteur de force. Le blocage neuromusculaire a été maintenu à 80 % par la perfusion cible contrôlée tout au long de l'intervention.Résultats : Les doses requises pour assurer une heure de myorelaxation ont été de 867 ± 116 µg·kg -1 ·h -1 chez les fumeurs (F) et de 839 ± 149 µg·kg -1 ·h -1 chez les non fumeurs (NF), P : NS. Le temps d'atteindre 10 % du bloc et la récupération spontanée de 25 % à 75 % des réponses par contractions contrôlées n'ont pas présenté de différences entre les patients du groupe F (17,2 ± 3,4 min, 10,6 ± 0,9 min ) et ceux du groupe NF (18,9 ± 4,3 min, 10,9 ± 3,2 min). Aucune différence n'est apparue pour le temps nécessaire à l'obtention du bloc maximal, le délai d'installation du bloc et le débit de la perfusion.Conclusion : L'habi...

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Section: Methodsmentioning

confidence: 99%

“…Skin temperature at the site of the surface electrodes was monitored and recorded continuously with the Relaxometer 2 6 and kept > 33.0°C.…”

Section: Methodsmentioning

confidence: 99%

Smoking does not alter the dose-requirements and the pharmacodynamics of rocuronium

Pühringer

Keller

Löckinger

et al. 2000

Can J Anesth/J Can Anesth

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“…The neuromuscular blocking effects were measured by mechanomyography using the Relaxometer (University of Groningen, The Netherlands) [5]. After induction of anaesthesia and calibration of the neuromuscular monitoring equipment, the ulnar nerve was stimulated at the wrist using surface electrodes.…”

Section: Neuromuscular Measurementsmentioning

confidence: 99%

Time course of action and intubating conditions following vecuronium, rocuronium and mivacurium

et al. 1995

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SummaryThe purpose of this study was to compare the time course of action and tracheal intubating conditions of vecuronium, rocuronium andmivacurium in anaesthetisedpatients. Anaesthesia consisted of thiopentone, fentanyl, N 2 0 / 0 2 and isoflurane. After a 2 x EDW dose thefrst attempt at tracheal intubation was made at 90s. Ifrequired, maintenance doses of 0.5 x EDw were administered.The intubating conditions after rocuronium were signiJicantly better than those after vecuronium and mivacurium. The average onset times of rocuronium (I 72 s) and vecuronium (I 92 s) were significantly shorter than that of mivacurium (229 s). The clinical duration and recovery time were significantly shorter after mivacurium (13 and 6min, respectively) than with vecuronium (33 and 14 rnin, respectivelys) and rocuronium (28 and 11 min, respectively). We conclude that rocuronium might be of advantage whenever the interval between the administration of the muscle relaxant and tracheal intubation must be short, whereas mivacurium may be of beneft i f fast spontaneous recovery is required.

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“…The arm was wrapped to keep the temperature of the hand above 32.58C. Preload was kept constant at 200-400 g. The isometric contraction of the adductor pollicis muscle was measured by a force transducer and recorded online (Relaxometer, Groningen, the Netherlands) [12]. Monitoring continued until the ST response recovered to its pre-relaxation control value.…”

Section: Anesthesiamentioning

confidence: 99%

Simultaneous versus sequential pharmacokinetic‐pharmacodynamic population analysis using an Iterative Two‐Stage Bayesian technique

Proost

Schiere

Eleveld

et al. 2007

Biopharm & Drug Disp

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A method for simultaneous pharmacokinetic-pharmacodynamic (PK-PD) population analysis using an Iterative Two-Stage Bayesian (ITSB) algorithm was developed. The method was evaluated using clinical data and Monte Carlo simulations. Data from a clinical study with rocuronium in nine anesthetized patients and data generated by Monte Carlo simulation using a similar study design were analysed by sequential PK-PD analysis, PD analysis with nonparametric PK data and simultaneous PK-PD analysis. Both PK and PD data sets were 'rich' with respect to the number of measurements per individual. The accuracy and precision of the estimated population parameters were evaluated by comparing their mean error (ME) and root mean squared error (RMSE), respectively. The influence of PD model misspecification on the results was also investigated. The simultaneous PK-PD analysis resulted in slightly more precise population parameter estimates than the sequential PK-PD analysis and the nonparametric PK method. In the presence of PD model misspecification, however, simultaneous analysis resulted in poor PK parameter estimates, while sequential PK-PD analysis performed well. In conclusion, ITSB is a valuable technique for PK-PD population analysis of rich data sets. The sequential PK-PD method is better suited for the analysis of rich data than the simultaneous analysis.

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The Relaxometer: A complete and comprehensive computer-controlled neuromuscular transmission measurement system developed for clinical research on muscle relaxants

Cited by 40 publications

References 23 publications

Smoking does not alter the dose-requirements and the pharmacodynamics of rocuronium

Smoking does not alter the dose-requirements and the pharmacodynamics of rocuronium

Time course of action and intubating conditions following vecuronium, rocuronium and mivacurium

Simultaneous versus sequential pharmacokinetic‐pharmacodynamic population analysis using an Iterative Two‐Stage Bayesian technique

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