Home About us Contact
|
Home About us Contact | ||
|
|
||
Neuromuscular Block (neuromuscular + block)
Selected AbstractsTime course of rocuronium-induced neuromuscular block after pre-treatment with magnesium sulphate: a randomised studyACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 3 2010C. CZARNETZKI Background: A previously published study suggested that pre-treatment with magnesium sulphate (MgSO4) had no impact on the speed of onset of rocuronium-induced neuromuscular block. We set out to verify this assumption. Methods: Eighty patients (18,60 years) were randomly allocated to MgSO4 60 mg/kg or placebo (saline). Study drugs were given intravenously for 15 min before induction of anaesthesia with propofol, sufentanil and rocuronium 0.6 mg/kg. Anaesthesia was maintained with a target-controlled propofol infusion. Neuromuscular transmission was measured using train-of-four (TOF)-Watch SX® acceleromyography. Results: Onset was analysed in 37 MgSO4 and 38 saline patients, and recovery in 35 MgSO4 and 37 saline patients. Onset time (to 95% depression of T1) was on average 77 [SD=18] s with MgSO4 and 120 [48] s with saline (P<0.001). The total recovery time (DurTOF0.9) was on average 73.2 [22] min with MgSO4 and 57.8 [14.2] min with saline (P<0.003). The clinical duration (Dur25%) was on average 44.7 [14] min with MgSO4 and 33.2 [8.1] min with saline (P<0.0002). The recovery index (Dur25,75%) was on average 14.0 [6] min with MgSO4 and 11.2 [5.2] min with saline (P<0.02). The recovery time (Dur25%TOF0.9) was on average 28.5 [11.7] min with MgSO4 and 24.7 [8.4] min with saline (P=0.28). Conclusion: Magnesium sulphate given 15 min before propofol anaesthesia reduces the onset time of rocuronium by about 35% and prolongs the total recovery time by about 25%. Trial Registration: Clinicaltrials.gov identifier: NCT00405977. [source] Knowledge of residual curarization: an Italian surveyACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 3 2010P. DI MARCO Background: The use of neuromuscular blocking agents (NMBAs) is widespread in anesthetic practice; little is known about the current use of these drugs in Italy. This survey was conducted to obtain information about the most commonly used clinical tests and the train-of-four (TOF) ratios that are considered as being reliable for assessing recovery from neuromuscular blockade at the end of anesthesia and the estimated occurrence rates of post-operative paralysis in Italian hospitals. Methods: The questionnaire was given to Italian anesthesiologists attending the 62nd National Congress of the Italian Society of Anesthesia, Analgesia and Intensive Therapy. Collected data were stratified by age and the total number of surgical procedures performed in the hospitals concerned. Results: Seven hundred and fifty-four correctly compiled questionnaires were collected (response rate 88.7%). Seventy three percent of the respondents only used clinical tests for monitoring the level of neuromuscular blockade. The main clinical tests cited for the evaluation of residual paralysis were keeping the head lifted up for 5 s, protruding the tongue and opening the eyes. TOF was used by 35% of the respondents on a routine basis. Only 24% of the interviewed anesthesiologists reported that before extubation, a TOF ratio of at least 0.9 should be reached. Conclusions: Most Italian anesthetists assess the recovery from neuromuscular blockade only by clinical signs. There is poor awareness about the inability of such techniques to indicate even a significant amount of residual neuromuscular block. A more extensive use of quantitative instrumental monitoring is required for the more rational use of NMBAs. [source] Infusion requirements and reversibility of rocuronium at the corrugator supercilii and adductor pollicis musclesACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 10 2009T. SUZUKI Background: The aim of this study is to compare the infusion rates required to maintain a constant neuromuscular block and the reversibility of rocuronium at the corrugator supercilii muscle (CSM) and the adductor pollicis muscle (APM). Methods: We randomly allocated 30 female patients into two groups of 15 patients each to monitor neuromuscular block at either the CSM or the APM. After induction of anaesthesia and laryngeal mask insertion, contraction of the CSM to the facial nerve stimulation or that of the APM to the ulnar nerve stimulation was quantified using an acceleromyograph during 1.0,1.5% end-tidal sevoflurane anaesthesia. All the patients received a bolus of 1 mg/kg rocuronium. When the first twitch (T1) of train-of-four (TOF) recovered to 10% of the control, rocuronium infusion was commenced and maintained at T1 of 10% of the control at the CSM or APM for 120 min. Immediately after rocuronium infusion was discontinued, the time required for 0.04 mg/kg neostigmine-facilitated recovery to a TOF ratio of 0.9 was recorded. Results: Rocuronium infusion dose after a lapse of 120 min was significantly larger in the CSM than in the APM [7.1 (2.3) vs. 4.7 (2.6) ,g/kg/min; P=0.001]. The time for facilitated recovery was shorter in the CSM than in the APM [11.4 (3.8) vs. 16.2 (6.0) min; P=0.016]. Conclusion: A larger rocuronium infusion dose was required to maintain a constant neuromuscular block at the CSM. Neostigmine-mediated reversal was faster at the CSM. [source] Objective monitoring of neuromuscular block should become the standard of careACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 6 2009M. El-Orbany No abstract is available for this article. [source] Improving the prediction of a neuromuscular blockACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 4 2009M. Eikermann No abstract is available for this article. [source] Attenuation of a rocuronium-induced neuromuscular block in patients receiving prednisoloneACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 4 2009S. SOLTÉSZ Background: This study tested the influence of continuous medication (more than 4 weeks) with prednisolone on a rocuronium-induced neuromuscular block. Methods: The time course of a rocuronium-induced neuromuscular blockade (0.3 mg/kg) was investigated in 40 patients with chronic inflammatory bowel disease undergoing elective abdominal surgery. The primary end point was the time from the start of injection of rocuronium until recovery of the TOF ratio to 0.9. Twenty patients received continuous medication with prednisolone (group A), and 20 were without glucocorticoid medication (group B). Additionally, another 20 patients without inflammatory bowel disease and without glucocorticoid medication served as control (group C). Results: The onset time was prolonged in group A [253 (51.2) s] compared with group B [187 (61.3) s]. Twitch height at the onset of the block was higher in group A [16.5 (0,61)%] than that in group B [5.0 (0,33)%]. The duration to 25% twitch height was shorter in group A [12.6 (0,20.7) min] compared with group B [16.7 (0,25.3) min] and group C [16.9 (0,29.3) min]. The recovery to a train-of-four ratio of 0.9 was reduced in group A [25.7 (23,34.3) min] compared with group B [34.7 (32.7,44.2) min] and group C [36.5 (31.7,42.3) min]. Conclusions: Prednisolone treatment in patients with inflammatory bowel disease is associated with a delayed onset and a shorter duration of action of rocuronium. The presence of an inflammatory bowel disease did not influence the neuromuscular block. [source] The place of suxamethonium in pediatric anesthesiaPEDIATRIC ANESTHESIA, Issue 6 2009MARCIN RAWICZ MD Summary Suxamethonium is a drug that promotes very strong views both for and against its use in the context of pediatric anesthesia. As such, the continuing debate is an excellent topic for a ,Pro,Con' debate. Despite ongoing efforts by drug companies, the popular view still remains that there is no single neuromuscular blocking drug that can match suxamethonium in terms of speed of onset of neuromuscular block and return of neuromuscular control. However, with this drug the balance of benefit vs risk and side effects are pivotal. Suxamethonium has significant adverse effects, some of which can be life threatening. This is particularly relevant for pediatric anesthesia because the spectrum of childhood diseases may expose susceptible individuals to an increased likelihood of adverse events compared with adults. Additionally, the concerns related to airway control in the infant may encourage the occasional pediatric anesthetist to use the drug in preference to slower onset/offset drugs. In the current environment of drug research, surveillance and licensing, it is debatable whether this drug would achieve the central place it still has in pediatric anesthesia. The arguments for and against its use are set out below by our two international experts, Marcin Rawicz from Poland and Barbara Brandom from USA. This will allow the reader an objective evaluation with which to make an informed choice about the use of suxamethonium in their practice. [source] Reversal of rocuronium-induced neuromuscular blockade by pyridostigmine in patients with Duchenne muscular dystrophyPEDIATRIC ANESTHESIA, Issue 3 2008TINO MUENSTER MD Summary Background:, The aim of this study was to investigate the effect and safety of pyridostigmine for the reversal of a neuromuscular block (NMB) in patients with Duchenne muscular dystrophy (DMD). In patients with DMD recovery from a rocuronium-induced NMB is markedly delayed. Methods:, Fourteen DMD patients (aged between 11 and 19 years) scheduled for elective scoliosis repair were studied. Following tracheal intubation without muscle relaxant, all patients received a single dose of rocuronium 0.6 mg·kg,1. NMB was monitored by acceleromyography at the adductor pollicis muscle. When the first twitch height (T1) of the train-of-four (TOF) had recovered to 25% seven patients received either pyridostigmine 0.1 mg·kg,1 (the anticholinergic drug with a long duration of action) or saline in a blinded manner. The times to attain TOF ratio of 0.9 were recorded. For comparison the Mann,Whitney U -test was used. Results:, Recovery to TOF ratio of 0.9 was significantly (P < 0.05) accelerated by pyridostigmine [84 (median), 57,141(range)] compared with controls (148, 84,243 min). The recovery time (time between T1 of 25% and TOF of 90%) was also significantly (P < 0.01) shortened by pyridostigmine (15, 8,49 vs 76, 43,144 min, respectively). Time to recovery of T1 to 90% was not different between the groups (108, 63,134 vs 169. 61,208 min, respectively). Conclusions:, Pyridostigmine 0.1 mg·kg,1 effectively reversed a rocuronium-induced NMB in DMD patients. [source] Intraspinally mediated state-dependent enhancement of motoneurone excitability during fictive scratch in the adult decerebrate catTHE JOURNAL OF PHYSIOLOGY, Issue 15 2010Kevin E. Power This is the first study to report on the increase in motoneurone excitability during fictive scratch in adult decerebrate cats. Intracellular recordings from antidromically identified motoneurones revealed a decrease in the voltage threshold for spike initiation (Vth), a suppression of motoneurone afterhyperpolarization and activation of voltage-dependent excitation at the onset of scratch. These state-dependent changes recovered within 10,20 s after scratch and could be evoked after acute transection of the spinal cord at C1. Thus, there is a powerful intraspinal system that can quickly and reversibly re-configure neuronal excitability during spinal network activation. Fictive scratch was evoked in spinal intact and transected decerebrate preparations by stroking the pinnae following topical curare application to the dorsal cervical spinal cord and neuromuscular block. Hyperpolarization of Vth occurred (mean ,5.8 mV) in about 80% of ipsilateral flexor, extensor or bifunctional motoneurones during fictive scratch. The decrease in Vth began before any scratch-evoked motoneurone activity as well as during the initial phase in which extensors are tonically hyperpolarized. The Vth of contralateral extensors depolarized by a mean of +3.7 mV during the tonic contralateral extensor activity accompanying ipsilateral scratch. There was a consistent and substantial reduction of afterhyperpolarization amplitude without large increases in motoneurone conductance in both spinal intact and transected preparations. Depolarizing current injection increased, and hyperpolarization decreased the amplitude of rhythmic scratch drive potentials in acute spinal preparations indicating that the spinal scratch-generating network can activate voltage-dependent conductances in motoneurones. The enhanced excitability in spinal preparations associated with fictive scratch indicates the existence of previously unrecognized, intraspinal mechanisms increasing motoneurone excitability. [source] Comparison of mechanomyography and acceleromyography for the assessment of rocuronium induced neuromuscular block in myotonic dystrophy type 1ANAESTHESIA, Issue 6 2010L. E. H. Vanlinthout Summary We measured acceleromyography and mechanomyography simultaneously with monitoring of rocuronium-induced neuromuscular block in four patients with myotonic dystrophy type 1. Furthermore, we compared neuromuscular block measures from these patients with those from normal controls from previous studies. In myotonic dystrophy type 1 patients, the dose-response curve obtained with acceleromyography was steeper and right-shifted compared with that obtained using mechanomyography. However, the effective doses to produce 95% neuromuscular block determined with both acceleromyography and mechanomyography were similar to each other and to values found in normal patients. In the three myotonic dystrophy type 1 patients with mild to moderate disease, times to recovery from block were similar to those observed in normal controls. In both patients and normal controls, neuromuscular block recovered faster with acceleromyography. However, in one patient with severe muscle wasting, recovery of neuromuscular block was prolonged. We conclude that mechanomyography and acceleromyography cannot be used interchangeably to monitor neuromuscular block in myotonic dystrophy type 1 patients. [source] The use of sugammadex in a patient with myasthenia gravisANAESTHESIA, Issue 3 2010C. 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] Management of neuromuscular block: time for a change?ANAESTHESIA, Issue 2009R. K. Mirakhur First page of article [source] Basic principles of neuromuscular transmissionANAESTHESIA, Issue 2009J. A. J. Martyn Summary Neuromuscular transmission at the skeletal muscle occurs when a quantum of acetylcholine from the nerve ending is released and binds to the nicotinic acetylcholine receptors on the postjunctional muscle membrane. The nicotinic acetylcholine receptors on the endplate respond by opening channels for the influx of sodium ions and subsequent endplate depolarisation leads to muscle contraction. The acetylcholine immediately detaches from the receptor and is hydrolysed by acetylcholinesterase enzyme. Suxamethonium is a cholinergic agonist stimulating the muscle nicotinic acetylcholine receptors prior to causing neuromuscular block. Non-depolarising neuromuscular blocking drugs bind to the nicotinic acetylcholine receptors preventing the binding of acetylcholine. Non-depolarising neuromuscular blocking drugs also inhibit prejunctional ,3,2 nicotinic acetylcholine autoreceptors, which can be seen in the clinical setting as train-of-four fade. In some pathological states such as denervation, burns, immobilisation, inflammation and sepsis, there is expression of other subtypes of nicotinic acetylcholine receptors with upregulation of these receptors throughout the muscle membrane. The responses of these receptors to suxamethonium and non-depolarising neuromuscular blocking drugs are different and explain some of the aberrant responses to neuromuscular blocking drugs. [source] Antagonism of non-depolarising neuromuscular block: current practiceANAESTHESIA, Issue 2009A. 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] Sugammadex in clinical practiceANAESTHESIA, Issue 2009R. K. Mirakhur Summary The availability of sugammadex allows greater flexibility in the use of rocuronium and vecuronium during anaesthesia and surgery. The neuromuscular block induced by both drugs can be reversed from both superficial and deep levels of block by adjusting the dose of sugammadex. The dose of sugammadex for reversal of shallow block produced by these neuromuscular blocking drugs is approximately 2 mg.kg,1 and for deep block the dose is 4 mg.kg,1. A larger dose of sugammadex (16 mg.kg,1) administered 3 min after the neuromuscular blocking drug allows rapid reversal of a neuromuscular block induced by 1,1.2 mg.kg,1 of rocuronium, thereby raising the possibility of using rocuronium as a replacement for suxamethonium. The use of sugammadex has not been reported to be associated with recurrence of block provided a dose that is adequate for reversal has been used. Sugammadex appears to have an acceptable safety profile. There are no requirements for dose adjustment for age or the use of potent volatile anaesthetic agents. [source] Neuromuscular blocking drugs and their antagonists in patients with organ diseaseANAESTHESIA, Issue 2009R. G. Craig Summary The pharmacodynamics and pharmacokinetics of the currently available neuromuscular blocking and reversal drugs may be altered by organ disease. Adverse effects such as prolonged neuromuscular block, postoperative residual curarisation, recurarisation, the muscarinic effects of the anticholinesterases, and the side-effects of the antimuscarinics are encountered more frequently. This review will consider these potential problems and assess the role of sugammadex in enabling the anaesthetist to avoid them. It will also present the latest knowledge regarding the safety and efficacy of sugammadex in patients with renal, hepatic, cardiovascular and pulmonary disease. [source] Clinical implications of sugammadexANAESTHESIA, Issue 2009J. E. Caldwell Summary Sugammadex is a cyclodextrin molecule that encapsulates and inactivates rocuronium and vecuronium. As a result, any degree of neuromuscular block produced by rocuronium or vecuronium can be rapidly and completely reversed without autonomic effects. Because sugammadex is optimised for reversing rocuronium it is most likely to be used in conjunction with this drug. Sugammadex will allow deep levels of block to be maintained until the very end of surgery, and will allow block to be reversed at any time after rocuronium administration, even just a few minutes. The recommended dose-range is 2,16 mg.kg-1 (ascender), depending on the level of block. The availability of sugammadex reversal may increase the use of rocuronium, and decrease the use of suxamethonium and benzylisoquinoline neuromuscular blocking drugs. In addition, it will certainly increase pharmacy costs, which may be offset by faster recovery and discharge from the post-anesthesia recovery unit. Sugammadex may also change monitoring practices in that post-tetanic count will be required to quantify deep block, and quantitative monitoring of recovery may be driven by cost concerns in order to allow the use of the smallest dose of sugammadex that gives a satisfactory train-of-four ratio. Alternatively, monitoring may essentially be abandoned since a large dose of sugammadex will reliably reverse any degree of rocuronium-induced block. The ultimate clinical utility of sugammadex will be clear only after large-scale clinical use. [source] Monitoring neuromuscular block: an updateANAESTHESIA, Issue 2009T. 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] | ||||||||||