Dosimetric feasibility study ("proof of concept") of refractory ventricular tachycardia radioablation using proton minibeams.

PURPOSE: Preclinical data demonstrated that the use of proton minibeam radiotherapy reduces the risk of toxicity in healthy tissue. Ventricular tachycardia radioablation is an area under clinical investigation in proton beam therapy. We sought to simulate a ventricular tachycardia radioablation with proton minibeams and to demonstrate that it was possible to obtain a homogeneous coverage of an arrhythmogenic cardiac zone with this technique. MATERIAL AND METHODS: An arrhythmogenic target volume was defined on the simulation CT scan of a patient, localized in the lateral wall of the left ventricle. A dose of 25Gy was planned to be delivered by proton minibeam radiotherapy, simulated using a Monte Carlo code (TOPAS v.3.7) with a collimator of 19 0.4 mm-wide slits spaced 3mm apart. The main objective of the study was to obtain a plan ensuring at least 93% of the prescription dose in 93% of the planning target volume without exceeding 110% of the prescribed dose in the planning target volume. RESULTS: The average dose in the planning treatment volume in proton minibeam radiotherapy was 25.12Gy. The percentage of the planning target volume receiving 93% (V93%), 110% (V110%), and 95% (V95%) of the prescribed dose was 94.25%, 0%, and 92.6% respectively. The lateral penumbra was 6.6mm. The mean value of the peak-to-valley-dose ratio in the planning target volume was 1.06. The mean heart dose was 2.54Gy versus 5.95Gy with stereotactic photon beam irradiation. CONCLUSION: This proof-of-concept study shows that proton minibeam radiotherapy can achieve a homogeneous coverage of an arrhythmogenic cardiac zone, reducing the dose at the normal tissues. This technique, ensuring could theoretically reduce the risk of late pulmonary and breast fibrosis, as well as cardiac toxicity as seen in previous biological studies in proton minibeam radiotherapy.

Fusion product measurements by nuclear diagnostics in the Joint European Torus deuterium-tritium 2 campaign (invited).

A new deuterium-tritium experimental, DTE2, campaign has been conducted at the Joint European Torus (JET) between August 2021 and late December 2021. Motivated by significant enhancements in the past decade at JET, such as the ITER-like wall and enhanced auxiliary heating power, the campaign achieved a new fusion energy world record and performed a broad range of fundamental experiments to inform ITER physics scenarios and operations. New capabilities in the area of fusion product measurements by nuclear diagnostics were available as a result of a decade long enhancement program. These have been tested for the first time in DTE2 and a concise overview is provided here. Confined alpha particle measurements by gamma-ray spectroscopy were successfully demonstrated, albeit with limitations at neutron rates higher than some 1017 n/s. High resolution neutron spectroscopy measurements with the magnetic proton recoil instrument were complemented by novel data from a set of synthetic diamond detectors, which enabled studies of the supra-thermal contributions to the neutron emission. In the area of escaping fast ion diagnostics, a lost fast ion detector and a set of Faraday cups made it possible to determine information on the velocity space and poloidal distribution of the lost alpha particles for the first time. This extensive set of data provides unique information for fundamental physics studies and validation of the numerical models, which are key to inform the physics and scenarios of ITER.

Clinical and dosimetric impact of totally implantable venous access devices in radiotherapy of supra diaphragmatic Hodgkin Lymphoma.

PURPOSE: To evaluate attenuation of the totally implantable vascular access device (TIVAD) and assess its clinical and dosimetric impact on radiotherapy (RT) of lymphoma patients. MATERIALS AND METHODS: The first part of the study consisted of an in vitro approach by irradiating the TIVAD with different electron and photon energies. The attenuation data measured were compared with data calculated by our treatment planning system. All patients treated by radiotherapy for Hodgkin's lymphoma with their TIVAD in the target volume were then reviewed to assess the clinical outcome and dosimetric comparison using different plan metrics. All patients were treated by 3D conformal radiotherapy (3DCRT) or intensity-modulated radiotherapy delivered by Helical Tomotherapy (HT). RESULTS: Nineteen patients treated for stage I-III HL were studied. Seven patients were treated exclusively on the side of TIVAD and 12 were treated bilaterally. Median prescription dose was 30Gy. No significant clinical or dosimetric differences were observed between the side of the TIVAD and the contralateral side in patients treated bilaterally. HT resulted in a significantly higher conformity index (P<0.0022) and a significantly lower healthy tissue coverage (P=0.0008) than 3DCRT. The observed attenuation was 79% for 6 MeV, 59% for 9 MeV, and 46% for 12 MeV for electrons and 9% for 4 MV, 8% for 6 MV, 5% for 10 MV and 15 MV and 3% for 20 MV for X photons. CONCLUSION: TIVADs induce significant beam attenuation when using electrons, which can be overcome by using high-energy photons or by creating an exclusion zone in when HT is used.

Access to innovative medicines for metastatic melanoma worldwide: Melanoma World Society and European Association of Dermato-oncology survey in 34 countries.

According to data from recent studies from Europe, a large percentage of patients have restricted access to innovative medicines for metastatic melanoma. Melanoma World Society and European Association of Dermato-oncology conducted a Web-based survey on access to first-line recommended treatments for metastatic melanoma by current guidelines (National Comprehensive Center Network, European Society for Medical Oncology [ESMO] and European Organization for Research and Treatment of Cancer/European Association of Dermato-oncology/European dermatology Forum) among melanoma experts from 27 European countries, USA, China, Australia, Argentina, Brazil, Chile and Mexico from September 1st, 2017 to July 1st, 2018. Data on licencing and reimbursement of medicines and the number of patient treated were correlated with the data on health expenditure per capita (HEPC), Mackenbach score of health policy performance, health technology assessment (HTA), ASCO and ESMO Magnitude of clinical benefit scale (ESMO MCBS) scores of clinical benefit and market price of medicines. Regression analysis for evaluation of correlation between the parameters was carried out using SPSS software. The estimated number of patients without access in surveyed countries was 13768. The recommended BRAFi + MEKi combination and anti-PD1 immunotherapy were fully reimbursed/covered in 19 of 34 (55.8%) and 17 of 34 (50%) countries, and combination anti-CTLA4+anti-PD1 in was fully covered in 6 of 34 (17.6%) countries. Median delay in reimbursement was 991 days, and it was in significant correlation with ESMO MCBS (p = 0.02), median market price (p = 0.001), HEPC and Mackenbach scores (p < 0.01). Price negotiations or managed entry agreements (MEAs) with national authorities were necessary for reimbursement. In conclusion, great discrepancy exists in metastatic melanoma treatment globally. Access to innovative medicines is in correlation with economic parameters as well as with healthcare system performance parameters. Patient-oriented drug development, market access and reimbursement pathways must be urgently found.

More than 5000 patients with metastatic melanoma in Europe per year do not have access to recommended first-line innovative treatments.

BACKGROUND: Despite the efficacy of innovative treatments for metastatic melanoma, their high costs has led to disparities in cancer care among different European countries. We analysed the availability of these innovative therapies in Europe and estimated the number of patients without access to first-line recommended treatment per current guidelines of professional entities such as the European Society for Medical Oncology (ESMO), the European Organisation for Research and Treatment of Cancer (EORTC), the European Association of Dermato-Oncology (EADO), and European Dermatology Forum (EDF). MATERIALS AND METHODS: Web-based online survey was conducted in 30 European countries with questions about the treatment schedules from 1st May 2015 to 1st May 2016: number of metastatic melanoma patients, registration and reimbursement of innovative medicines (updated data, as of 1st October 2016), percentage of patients treated and availability of clinical studies and compassionate-use programmes. RESULTS: The recommended BRAF inhibitor (BRAFi) + MEK inhibitor (MEKi) combination was both registered and fully reimbursed in 9/30 (30%) countries, and in 13/30 (43%) (all from Eastern Europe) not reimbursed. First-line immunotherapy with anti-PD1 antibodies was registered and fully reimbursed in 14/30 (47%) countries, while in 13/30 (43%) (all from Eastern Europe) not reimbursed. It was estimated that in Europe 19,600 patients with metastatic melanoma are treated, and 5238 (27%) do not have access to recommended first-line therapy. Significant correlation was found between human development index (HDI, UNDP report 2015), (r = 0.662; p < 0.001), health expenditure per capita (r = 0.695; p < 0.001) and the Mackenbach score of health policy performance (r = 0.765; p < 0.001) with the percentage of patients treated with innovative medicines and a number of reimbursed medicines. CONCLUSIONS: Great discrepancy exists in metastatic melanoma treatment across Europe. It is crucial to increase the awareness of national and European policymakers, oncological societies, melanoma patients' associations and pharma industry.

An arc control and protection system for the JET lower hybrid antenna based on an imaging system.

Arcs are the potentially most dangerous events related to Lower Hybrid (LH) antenna operation. If left uncontrolled they can produce damage and cause plasma disruption by impurity influx. To address this issue an arc real time control and protection imaging system for the Joint European Torus (JET) LH antenna has been implemented. The LH system is one of the additional heating systems at JET. It comprises 24 microwave generators (klystrons, operating at 3.7 GHz) providing up to 5 MW of heating and current drive to the JET plasma. This is done through an antenna composed of an array of waveguides facing the plasma. The protection system presented here is based primarily on an imaging arc detection and real time control system. It has adapted the ITER like wall hotspot protection system using an identical CCD camera and real time image processing unit. A filter has been installed to avoid saturation and spurious system triggers caused by ionization light. The antenna is divided in 24 Regions Of Interest (ROIs) each one corresponding to one klystron. If an arc precursor is detected in a ROI, power is reduced locally with subsequent potential damage and plasma disruption avoided. The power is subsequently reinstated if, during a defined interval of time, arcing is confirmed not to be present by image analysis. This system was successfully commissioned during the restart phase and beginning of the 2013 scientific campaign. Since its installation and commissioning, arcs and related phenomena have been prevented. In this contribution we briefly describe the camera, image processing, and real time control systems. Most importantly, we demonstrate that an LH antenna arc protection system based on CCD camera imaging systems works. Examples of both controlled and uncontrolled LH arc events and their consequences are shown.

Effects of magnetic shear on toroidal rotation in tokamak plasmas with lower hybrid current drive.

Application of lower hybrid (LH) current drive in tokamak plasmas can induce both co- and countercurrent directed changes in toroidal rotation, depending on the core q profile. For discharges with q(0) <1, rotation increments in the countercurrent direction are observed. If the LH-driven current is sufficient to suppress sawteeth and increase q(0) above unity, the core toroidal rotation change is in the cocurrent direction. This change in sign of the rotation increment is consistent with a change in sign of the residual stress (the divergence of which constitutes an intrinsic torque that drives the flow) through its dependence on magnetic shear.

Effects of airway occlusion on breathing muscle electromyogram signals, during isoflurane anaesthesia, with and without the effects of fentanyl and hypercapnia.

BACKGROUND: Expiratory muscle action is prominent during anaesthesia and can impair lung function. This activity is exaggerated by the use of opioids. Airway pressure during occlusion of expiration would be a valuable measure in the study of expiratory muscle activation. However, this would only be valid if the imposed occlusion did not itself alter muscle activation. This possibility can be checked by directly assessing muscle activity by electromyography; varying arterial carbon dioxide tensions and opioid action should be considered. METHODS: We studied seven spontaneously breathing patients, anaesthetized with nitrous oxide and isoflurane, in four conditions: during an infusion of fentanyl and after naloxone, breathing normally and with breathing stimulated with CO(2). We compared diaphragm and external oblique abdominal electromyogram (EMG) signals during normal and occluded breaths. We also measured chest wall volume and compared airway occlusion pressure, during inspiration and expiration, with the EMG results. RESULTS: Inspiratory occlusion increased the duration of inspiration during hypercapnia by 20%, but not the rate of electrical activation of the diaphragm, indicating that occlusion does not cause a reflex increase in diaphragm contraction. In contrast, expiratory occlusion did not affect either the duration of expiration or the electrical activity of the external oblique muscles. CONCLUSIONS: In these conditions, except for a change in inspiratory duration, respiratory muscle activity is unaffected by airway occlusion. Airway occlusion will permit valid measures of muscle activity in inspiration and expiration and provide simple measurements of respiratory muscle function during anaesthesia.

[Radiotherapy for breast cancer and pacemaker]. / Radiothérapie pour un cancer du sein et stimulateur cardiaque.

PURPOSE: Patients with permanent cardiac pacemakers occasionally require radiotherapy. Therapeutic irradiation may cause pacemakers to malfunction due to the effects of ionizing radiation or electromagnetic interference. We studied the breast cancer patients who needed breast and/or chest wall and lymph node irradiation to assess the feasibility and tolerance in this population of patients. PATIENTS AND METHODS: From November 2008 to December 2009, more than 900 patients received radiotherapy for their breast cancer in our department using megavoltage linear accelerator (X 4-6 MV and electrons). Among them, seven patients were with permanent pacemaker. All patients have been treated to the breast and chest wall and/or lymph nodes. Total dose to breast and/or chest wall was 50 Gy/25 fractions and 46 Gy/23 fractions to lymph nodes. Patients who underwent conserving surgery followed by breast irradiation were boosted when indicated to tumour bed with 16 Gy/8 fractions. All patients were monitored everyday in presence of radiation oncologist to follow the function of their pacemaker. All pacemakers were controlled before and after radiotherapy by the patients' cardiologist. RESULTS: Seven patients were referred in our department for postoperative breast cancer radiotherapy. Among them, only one patient was declined for radiotherapy and underwent mastectomy without radiotherapy. In four cases the pacemaker was repositioned before the beginning of radiotherapy. Six patients, aged between 48 and 84 years underwent irradiation for their breast cancer. Four patients were treated with conserving surgery followed by breast radiotherapy and two with mastectomy followed by chest wall and internal mammary chain, supra- and infra-clavicular lymph node irradiation. The dose to the pacemaker generator was kept below 2 Gy. There was no pacemaker dysfunction observed during the radiotherapy. CONCLUSION: The multidisciplinary work with position change of the pacemaker before radiotherapy and everyday monitoring permitted the safe treatment of our patients. Updated guidelines are definitely needed with more details about acceptable doses at the different parts of the pacemaker.

Dose-response effect of serum butyrylcholinesterase activity after clinical doses of pancuronium.

INTRODUCTION: Low-dose pancuronium is known to affect serum cholinesterase activity (BChE); however, the dose-response effect of clinical doses of pancuronium on BChE has not been investigated. METHODS: Thirteen ASA I-II patients scheduled for elective surgery requiring muscle relaxation were enrolled in this study. All patients had normal BChE before surgery. Incremental doses of pancuronium (10, 20, 50, and 100 microg/kg) were injected in accordance with surgical needs every 45 min. BChE was measured 3 min after injection by an automatic colorimetric method. RESULTS: BChE decreased significantly in all except one patient in comparison to the baseline (P < 0.05). However all values remained within normal clinical range. A dose of 100 microg/kg yielded significant decrease in comparison to 10 microg/kg but not to other dosages. Linear regression was not significant for the dose-response relationship (P = 0.05). CONCLUSION: After clinical incremental doses of pancuronium, BChE remained within clinical range.

Post-tetanic count at adductor pollicis is a better indicator of early diaphragmatic recovery than train-of-four count at corrugator supercilii.

BACKGROUND: Because the intensity of neuromuscular block at the diaphragm (DIA) is indirectly assessed, the electromyographic measurements of the DIA (DIA(EMG)) from surface electrodes were related to information provided by visual estimation of neuromuscular transmission at the adductor pollicis (AP) and the corrugator supercilii (CSC) during recovery from vecuronium block. METHODS: Twelve adult patients were studied during balanced anaesthesia. After induction of anaesthesia and tracheal intubation without neuromuscular blocking agent, supramaximal stimulations were applied to phrenic, ulnar and facial nerves. During recovery from vecuronium 0.1 mg kg(-1) an independent observer blinded to DIA(EMG) counted visually detectable train-of-four (TOF) at CSC (TOF(CSC)) and post-tetanic AP (PTC(AP)) responses. Times to recovery of PTC(AP) = 1, 10, and TOF(CSC) = 1-4 responses were related to DIA(EMG). Values are means (sd). RESULTS: Reappearance of the first response to PTC(AP) occurred significantly (P < 0.05) earlier and for a lower recovery of DIA(EMG) than that of TOF(CSC) [24 (8) min vs 33 (9) min, and 10 (10)% vs 25 (8)%, respectively]. With PTC(AP)

TOF count at corrugator supercilii reflects abdominal muscles relaxation better than at adductor pollicis.

BACKGROUND: A recovery profile from neuromuscular block similar to that of abdominal (AB) muscles, but different to that of the adductor pollicis (AP) muscle, has been demonstrated at the corrugator supercilii (CSC) muscle. We hypothesized that neuromuscular transmission (NMT) monitoring of CSC might provide useful information on AB relaxation compared with AP. We compared the visual estimation of NMT at CSC and AP with electromyographic measurements of AB during recovery from a vecuronium block. METHODS: Ten adult patients were studied during balanced anaesthesia. After induction of anaesthesia and tracheal intubation without neuromuscular blocking agents, supramaximal stimulations were applied to three nerves: left 10th intercostal, ulnar, and facial. Electromyographic activity (EMG) of AB was measured (ABemg). After a bolus dose of vecuronium 0.1 mg kg-1, an independent observer blinded to the EMG measurements counted visually detectable train-of-four (TOF) responses at CSC and AP. Values of ABemg associated with 1 to 4 TOF responses at CSC and AP were compared. Values are means (sd). RESULTS: Reappearance of the first and second TOF responses at CSC occurred significantly (P<0.05) earlier and at lower ABemg recovery than that of AP [35 (8) and 41 (9) min vs 51 (10) and 56 (12) min; and 17 (8) and 26 (9)% vs 56 (10) and 75 (11)%, respectively]. CONCLUSIONS: We demonstrated that the TOF response count at the CSC, compared with the AP, allowed a better quantification of the degree of AB muscle relaxation during recovery from vecuronium block.

[Rare endocrine tumors of the pancreas with secretion of cortisol].

UNLABELLED: The endocrine part of the pancreas consist 2% from the mass of the gland and it is built from little cells with name Langerhan's islands. The increased secretion of cells provokes to appearance of classic clinical syndrome, which is conditioned by large quantity of hormone in circulation of the blood. The endocrine tumors of the pancreas (ETP) are arisen out of cells that have large quantity to APUD-system. MATERIAL AND METHOD: We present a case report of rare ETP with secretion of cortisol (MEN2 syndrome), which is of interest by reason of the fact that this case report is the first announce in Bulgaria about similar tumor. Corporocaudal resention of the pancreas with spleenectomy has been made. RESULTS: Tumor cells with highly expresion (+++) of hromogranin were determined. The histological conclusion was malignant ETP (APUD system tumor)with secretion of cortisol. A decrease of the level of glucose in blood circulation, a decrease of blood pressure and reduction of the body weight were determined with range of first three postoperative weeks. CONCLUSION: The aims of the surgical therapy are a control over the level of hormones, clear resection and maximal organ saving operation.

Does repetition of post-tetanic count every 3 min during profound relaxation affect accelerographic recovery of atracurium blockade?

BACKGROUND: Post-tetanic count is a valuable method to assess profound neuromuscular blockade. However, subsequent responses to repetitive stimulation might be altered due to post tetanic facilitation (PTF). To avoid PTF, it has been advocated to limit the interval of stimulation from 6 to 10 min. The impact of PTF on 90% recovery of the TOF ratio has not been evaluated. Therefore, we assessed the effect of repetitive PTC stimulation on atracurium blockade with the primary outcome being the time to reach 90% TOF recovery in comparison to classical TOF stimulation. METHODS: After informed consent 20 patients ASA I-II, scheduled for peripheral surgery under general anaesthesia and requiring tracheal intubation were enrolled into the study. Anaesthesia was induced with fentanyl, propofol, and atracurium, 0.5 mg kg(-1). Neuromuscular characteristics were assessed at the adductor pollicis by a TOF Watch((R)) accelerometer (Organon, Teknika, Holland) on each arm. After onset of maximum neuromuscular blockade, repetitive PTC every 3 min on one arm and repetitive TOF stimulation every 15 s on the opposite arm was performed. The following parameters were recorded: onset of maximum blockade, mean time of PTC stimulation, the maximum number of responses to PTC, time of the first and second TOF responses, and recovery profile until 90% TOF ratio. RESULTS: Time to reach 90% TOF recovery was similar on both arms (48 +/- 9 min), with a difference of 16 +/- 38 s between the arms (P = 0.64). The first and second responses of the TOF on the PTC-stimulated arm appeared at 29 +/- 8 min and 33 +/- 7 min, respectively. On the other arm the responses appeared at 30 +/- 8 min and 35 +/- 8 min, respectively (P < 0.05). CONCLUSION: Repetitive PTC stimulation every 3 min hastened the first and second responses of the TOF stimulation but we could not detect a significant difference in the 90% recovery of TOF ratio during atracurium blockade.

Interaction between mivacurium and pancuronium: impact of the order of administration.

INTRODUCTION: Potentiation of mivacurium by low-dose pancuronium is mostly due to an inhibition of plasma butyryl cholinesterase (BchE) resulting in a decreased rate of hydrolysis of mivacurium. Nevertheless, an interaction at the receptor site could not be ruled out. By changing the order of the muscle relaxant injections, we may lessen the pharmacokinetic interaction and assess the impact at the acetylcholine receptor level. METHODS: Twenty patients scheduled for general anesthesia with propofol and fentanyl, and isoflurane were randomized into two groups receiving, mivacurium 100 microg kg-1 followed by pancuronium 15 microg kg-1 (group 1) or pancuronium 15 microg kg-1 followed by mivacurium 100 microg kg-1 (group 2). BchE before and after injection of each relaxant was measured. Neuromuscular block was assessed with a force transducer at the adductor pollicis measuring the elicited twitch to ulnar nerve stimulation. RESULTS: The neuromuscular block was greater when pancuronium was administered before mivacurium (100% versus 96+/-3%; P<0.05). Times to recovery of the elicited twitch response to 25% and 75% of control value were increased by 100% (P<0.05). After pancuronium, decreases in BchE of 11% and 14% in groups 1 and 2 were observed, respectively. CONCLUSION: Interaction between mivacurium and low dose pancuronium is significant only when mivacurium is injected after pancuronium.

Plasma rotation induced by directed waves in the ion-cyclotron range of frequencies.

Changes of the toroidal plasma rotation induced by directed waves in the ion-cyclotron range of frequencies (ICRF) have been identified experimentally for the first time on the JET tokamak. The momentum carried by the waves is initially absorbed by fast resonating ions, which subsequently transfer it to the bulk plasma. Thus, the results provide evidence for the influence of ICRF heated fast ions on plasma rotation.

[The case of diagnostic difficulties of submucous myoma in early pregnancy]. / Diagnostichni trudnosti pri ranna bremennost s nalichna submukozna mioma--kazus.

The authors describe observed case of pregnancy and degenerative submucous myoma. Diagnostic difficulties.

Comparison of the neuromuscular blocking effect of cisatracurium and atracurium on the larynx and the adductor pollicis.

BACKGROUND: Cisatracurium unlike atracurium is devoid of histamine-induced cardiovascular effects and this alone would be the greatest advantage in replacing atracurium for the facilitation of tracheal intubation. On the other hand, 2 ED(95) doses of cisatracurium (100 micro g/kg) do not yield satisfactory intubating conditions such as those seen with equipotent doses of atracurium and therefore the recommended intubating dose of cisatracurium is 3 ED(95). To understand this discrepancy better, we evaluated the potency and onset of atracurium and cisatracurium directly at the larynx adductors in humans. METHODS: The study was conducted in 54 patients (ASA class I or II) undergoing peripheral surgery requiring general anesthesia. Cisatracurium 25-150 micro g/kg or atracurium 120-500 micro g/kg intravenous (i.v.) boluses doses were administered during anesthesia with propofol, nitrous oxide, oxygen and fentanyl. Neuromuscular block was measured by electromyography (single twitch stimulation every 10 s) at the larynx and the adductor pollicis. The dose-response effect measured at both muscles included maximum neuromuscular blockade achieved (Emax), the time to maximum depression of twitch height (onset) and time to spontaneous recovery of the twitch height to 25%, 75% and 90% (T25, T75, T90) of control value. RESULT: The onset at the larynx was of 196 +/- 28 s after the 100 micro g/kg cisatracurium dose compared with 140 +/- 14 s after the 500 micro g/kg atracurium dose (P < 0.05). Emax at the larynx was 92 +/- 1% and 98 +/- 1% after 100 micro g/kg cisatracurium and 500 micro g/kg atracurium, respectively (P < 0.05). The time to onset of maximum suppression Emax = 100 +/- 0% after a 150 micro g/kg cisatracurium dose was 148 +/- 29 s. At the larynx, the ED(50) was 25 micro g/kg for cisatracurium and 180 micro g/kg for atracurium and the ED(95) was 87 micro g/kg for cisatracurium compared with 400 micro g/kg for atracurium. CONCLUSION: The slow onset time at the laryngeal muscles after cisatracurium can be explained by the higher potency as compared with atracurium.

Comparison between the Datex-Ohmeda M-NMT module and a force-displacement transducer for monitoring neuromuscular blockade.

BACKGROUND AND OBJECTIVE: The Datex-Ohmeda neuromuscular transmission module (M-NMT) is a new monitor that is part of the AS/3 anaesthesia monitor. It incorporates a mechanosensor, which is a piezoelectric polymer attached to the hand. The module was compared with a force transducer in 30 patients requiring neuromuscular blockade. METHODS: Anaesthesia was induced with fentanyl and propofol, and tracheal intubation was performed without muscle relaxants. Neuromuscular blockade was assessed by the test module on one arm and the force transducer on the other arm. When the response to train-of-four stimulation had been stable in both arms for 3 min, rocuronium 0.2 mg kg(-1) was injected intravenously. During recovery from blockade, the train-of-four ratio was measured in 15 patients, and the ratio of response to double-burst stimulation in the other 15 patients. Data analysis was by difference plots. RESULTS: Both devices had acceptable coefficients of repeatability. The M-NMT module was biased by + 1.3% (upper limit of agreement 14.2%, lower limit -12.9%) for the recovery of the train-of-four ratio, and by + 1.09% (17%, -16%) for the recovery of double-burst stimulation ratio. CONCLUSIONS: The Datex-Ohmeda M-NMT gives measurements that are repeatable and gives good enough correspondence with a force transducer that it can be used clinically to assess recovery of neuromuscular blockade, but the limits of agreement rule out research applications.

Effect of metoclopramide on mivacurium-induced neuromuscular block.

In order to investigate the effect of metoclopramide on the duration of action of mivacurium, 45 patients were randomized into three groups. Group M10 (n = 15) and M20 (n = 15) received 10 and 20 mg of metoclopramide i.v., respectively, and group S (n = 15) received saline 2 min before induction of anesthesia with fentanyl, thiopental and mivacurium. Plasma cholinesterase activity (pCHE) was measured before induction of anesthesia and 2 min after injection of metoclopramide and saline. Neuromuscular block was monitored by a force transducer using train of four nerve stimulation. Anesthesia was maintained with isoflurane and N2O. Time to recovery of a twitch height of 90% was significantly prolonged in group M10 and M20 (44 +/- 15 and 57 +/- 10 min) as compared to group S, 32 +/- 9 min, P < 0.05). A slight but significant decrease in pCHE was observed in group M20. Because of the risk of prolonged duration of action of mivacurium, neuromuscular blockade should always be monitored whenever metoclopramide is given before injection of mivacurium.