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J Viby-Mogensen

Publications and source records attributed to J Viby-Mogensen.

At least 19 recordsLinked to original sources
PubMed2004

Remifentanil vs. alfentanil infusion in non-paralysed patients: a randomized, double-blind study.

BACKGROUND AND OBJECTIVE: Remifentanil has a short duration of action and constant elimination, which allow administration of high doses, without prolonging recovery. Remifentanil has been compared to alfentanil, as part of a total intravenous anaesthetic technique, where remifentanil provided better anaesthetic conditions than alfentanil, without adverse effect on recovery. However, these results were obtained during anaesthesia involving neuromuscular blockade, which may mask both signs of insufficient anaesthesia and side-effects such as muscle rigidity. The aim of this study was to compare remifentanil with alfentanil for anaesthesia without neuromuscular blockade. METHODS: We performed a prospective, randomized, double-blind, four-centre study to compare remifentanil infusion 15 microg kg(-1) h(-1) and alfentanil infusion 60 microg kg(-1) h(-1), using a total intravenous technique for non-paralysed patients, and the laryngeal mask airway for airway management. We enrolled 192 patients, 18-65 yr of age with ASA I-II, undergoing minor surgery. The primary endpoint was the number of patients having pre-defined responses to surgical stimulation. A number of secondary criteria was evaluated to assess undesirable properties of the procedures. RESULTS: In the alfentanil group, 85% of patients responded to surgical stimulation, vs. 35% in the remifentanil group (P < 0.0001). No difference was found in recovery data, or in any other parameter than those related to insufficient anaesthesia. CONCLUSIONS: The remifentanil-based technique provided significantly better anaesthetic conditions than the alfentanil-based technique in the setting of this study, without causing any significant adverse effects.

Adolescent↗
PubMed2004

Scandinavian research in anaesthesiology 1981-2000: visibility and impact in EU and world context.

BACKGROUND: We wished to assess the development in number and impact of publications in anaesthesiology and intensive care medicine from 1981 to 2000 in the four Scandinavian countries: Sweden, Norway, Finland, and Denmark. For comparison, we also analyzed data from the UK and the Netherlands. METHODS: Publication and citation data from 1981 to 2000 were gathered from National Science Indicators (2001), covering 33 journals indexed in Current Contents. Data were analyzed in running 5-year periods. The following informetric indicators were used: absolute number of publications; absolute number of citations; absolute citation impact (average number of citations per publication per 5-year period); citation impact relative to the European Union and the world; and the percentage of cited papers from each country. RESULTS: The annual number of publications from Denmark was stable over the 20-year period. Sweden increased its production by 35%, while the remaining four countries showed increases from 100% to 146%. Thus, Sweden and Denmark lost visibility within the European Union (EU) and in world context. The EU and world citation shares of Finland and Norway increased slightly, whereas those of Sweden, Denmark, the UK, and the Netherlands all declined significantly. The absolute citation impact (ACI) increased for all the four Scandinavian countries. The ACI of the Netherlands did not change and was surpassed by all the Scandinavian countries by 1994-98, while the UK finished below the other five countries. CONCLUSIONS: (1) The annual number of publications from Sweden, Norway, Finland, the UK, and the Netherlands increased after the late eighties, whereas the net publication output from Denmark was stagnant over the 20-year period investigated; (2) the international publication and citation visibility of Finland and Norway increased slightly, as opposed to the significant decrease seen by the other four countries; (3) judging from the increase in absolute and relative citation impact and in the percentage of cited papers, the recognition of publications from the four Scandinavian countries increased over the past 20 years.

Anesthesiology↗
PubMed2003

Pharmacokinetics and pharmacodynamics of mivacurium in patients phenotypically heterozygous for the usual and atypical plasma cholinesterase variants (UA).

BACKGROUND: Mivacurium is hydrolyzed by plasma cholinesterase (pChe). The purpose of this study was to evaluate the pharmacodynamics and the pharmacokinetics of the three isomers of mivacurium in patients phenotypically heterozygous for the usual and the atypical pChe variant (UA). METHODS: Thirty-two patients were included in a dose-response study, in which the patients received one of four doses of mivacurium. An additional bolus dose of mivacurium, to a total of 0.1 mg kg-1, was given followed by a continuous infusion adjusted to maintain 91-99% neuromuscular block. The times to different levels of recovery following the infusion were measured using mechanomyography and train-of-four (TOF) nerve stimulation. Twelve of the patients with an estimated duration of anaesthesia of more than 90 min were (randomly) selected for the pharmacokinetic part of the study. Venous samples were taken for determination of the three isomers of mivacurium. These results were compared with results from a previous study in phenotypically normal patients (UU). RESULTS: The estimated ED50 and ED95 were 24 and 69 microg kg-1, respectively. The median (range) infusion rate was 3.7 microg kg-1 min-1 (1.2-2.9) and the time to a TOF ratio of 0.7 was 29.8 min (16.1-44.8). The median clearances of the cis-cis, cis-trans and trans-trans isomers were 3.7, 29 and 28 ml kg-1 min-1, respectively. The elimination half-lives of the isomers were 45, 6.7 and 6.3 min, respectively. CONCLUSION: In patients heterozygous for the usual and the atypical variant (UA), the potency of mivacurium is higher, the infusion requirements lower and the rate of spontaneous recovery prolonged, compared with phenotypically normal patients. The clearances of the active isomers are significantly lower and the elimination half-lives longer in heterozygous patients than in phenotypically normal patients (UU). The pharmacokinetics of the inactive cis-cis isomer was not affected.

Adolescent↗
PubMed2002

Postoperative muscle paralysis after rocuronium: less residual block when acceleromyography is used.

BACKGROUND: Residual muscle paralysis after anesthesia is common after pancuronium, but less common following the intermediate-acting drugs vecuronium and atracurium. Therefore, many anesthetists do not monitor neuromuscular function when using an intermediate-acting agent. The purpose of this prospective, randomised and double-blind study was to establish the incidence and degree of postoperative residual block following the use of rocuronium in patients not monitored with a nerve stimulator, and to compare it with results obtained in patients monitored using acceleromyography (AMG). METHODS: During propofol/opioid anesthesia, 120 adult patients were randomised to two groups, one monitored with AMG, the other using only clinical criteria without a nerve stimulator. Postoperatively, TOF-ratio was measured with mechanomyography; a TOF-ratio < 0.80 indicated residual muscle paralysis. RESULTS: Residual muscle paralysis was found in 10 patients in the group without neuromuscular monitoring (16.7%) (95% confidence interval, 12-21%) and in two patients in the AMG-monitored group (3%) (95% CI, 0-8%); (P = 0.029, Fisher's exact test). Time from end of surgery to tracheal extubation was significantly longer in the AMG-monitored group (12.5 min) than in the group not monitored with AMG (10 min). CONCLUSION: Clinical evaluation of recovery of neuromuscular function does not exclude significant residual paralysis following the intermediate-acting muscle relaxant rocuronium, but the problem of residual block can be minimized by use of AMG.

Adolescent↗
PubMed2002

The pharmacodynamics and pharmacokinetics of mivacurium in children.

BACKGROUND: In children, onset time and duration of action of mivacurium are shorter than in adults. Some suggest that this is due to differences in plasma cholinesterase (pChe), whereas others indicate that there is no difference. The purpose of this study was to evaluate the pharmacodynamics and pharmacokinetics of mivacurium in phenotypically normal children aged 3-6 and 10-14 years old, respectively. METHODS: Ten children aged 3-6 years and 10 children aged 10-14 years were studied during halothane anaesthesia. Before induction of anaesthesia, a blood sample was drawn to measure the pChe activity and phenotype. The neuromuscular block was monitored at the thumb using train-of-four (TOF) nerve stimulation every 12 s and mechanomyography. The times to different levels of neuromuscular recovery following mivacurium 0.2 mg/kg were recorded. The concentrations in venous blood of the three isomers and the metabolites of mivacurium were measured. RESULTS: No statistically significant difference was found in pChe activity or in the pharmacodynamics of mivacurium. The onset time was 1.4 min (0.8-1.9) median (range) and 1.3 min (1.1-1.9) and the time to first response to TOF nerve stimulation was 9.6 min (6.5-12.6) and 10.5 min (7.0-14.0) in young and older children, respectively. The pharmacokinetic data were too sparse to allow analysis of the two age groups separately (8 and 8 patients), hence the data were pooled. The median clearances of the cis-cis, the cis-trans, and the trans-trans isomer were 5.5, 51.0 and 30.5 ml/kg/min, respectively. CONCLUSION: Our data indicate that there are no major differences in pharmacodynamics or pharmacokinetics of mivacurium between young (3-6 years) and older (10-14 years) children.

Adolescent↗
PubMed2002

Plasma cholinesterase activity and duration of action of mivacurium in phenotypically normal patients.

BACKGROUND: The short duration of action of mivacurium is due to its rapid hydrolysis by plasma cholinesterase (pChe). In patients with normal phenotype, low pChe activity because of, for instance, disease or intake of drugs may prolong the duration of action of mivacurium. The purpose of this study was to evaluate the relationship between pChe activity and the duration of action of mivacurium 0.2 mg/kg in phenotypically normal patients. MATERIAL: Forty-three adult patients with normal pChe phenotype and low or normal pChe activity, undergoing a variety of surgical procedures were included in the study with their informed consent and Ethics Committee approval. The neuromuscular block was monitored using TOF stimulation every 12 s and mechanomyography. The time to reappearance of the first response to TOF stimulation was measured. RESULTS: The patients pChe activities ranged from 45 to 1272 U/l (normal range 660-1620 U/l) and the time to first response to TOF from 8.1 to 62.7 min. An inverse relationship between enzyme activity and duration of action of mivacurium was found. The relationship was described by the equation: log10 (time) =alpha- beta log10 (pChe), where alpha (SD) is 2.547 (0.186) and beta (SD) 0.454 (0.069). CONCLUSION: In patients with phenotypically normal pChe, prediction of the duration of action of mivacurium is possible from the patients actual pChe activity. In patients with pChe activities below the normal range, the time to reappearance of the first response to TOF stimulation may vary from 10 to 180 min Only patients with pChe activities <220 U/l had a significantly prolonged duration of action of mivacurium.

Adult↗
PubMed2002

Pharmacokinetics and pharmacodynamics of mivacurium in young adult and elderly patients.

BACKGROUND: Mivacurium is hydrolyzed by plasma cholinesterase, and is therefore less dependent on liver metabolism and renal elimination than other neuromuscular blocking drugs. This might favor the use of mivacurium in elderly patients. The purpose of this study was to compare the pharmacodynamics and the pharmacokinetics of the three isomers of mivacurium and their metabolites in young adult and elderly patients. METHODS: Sixty-four patients were included in a dose-response study, in which 32 young adults and 32 elderly patients received one of four doses of mivacurium. An additional bolus dose of mivacurium to a total of 0.1 mg/kg was given followed by a continuous infusion adjusted to maintain a 91-99% neuromuscular block. The times to maximum block and different levels of recovery were measured using mechanomyography and train-of-four (TOF) nerve stimulation. Thirty-two patients were randomly selected for the pharmacokinetic study. Venous samples were taken for determination of the three mivacurium isomers and the metabolites. RESULTS: The estimated ED95 were 0.053 and 0.061 mg/kg in young adults and elderly patients, respectively (NS). The median infusion rate did not differ, but duration to a TOF ratio of 0.7 was significantly longer in elderly patients than in young adult patients (21.0 vs. 16.5 min). No statistically significant difference between the age groups in clearance and elimination half-life of the isomers was seen. The half-lives of the metabolites were significantly prolonged in the elderly patients. CONCLUSION: There were no significant differences in the potency or infusion requirements between the adult and elderly patients, but the rate of recovery was significantly, though only moderately prolonged, in the elderly patients. No significant difference in clearance was seen but the elimination half-lives of the metabolites was longer in the elderly patients.

Adolescent↗
PubMed2002

Acceleromyography of the orbicularis oculi muscle I: significance of the electrode position.

BACKGROUND: This study aimed to establish the best position of the stimulating electrodes for facial nerve stimulation during acceleromyographic monitoring from the orbital part of the orbicularis oculi muscle. METHODS: In 59 anaesthetised patients, an acceleration transducer was positioned over the middle of the eyebrow. In 47 patients, supramaximal train-of-four (TOF) stimulation was established for four electrode pairs with different positions along the facial nerve and behind the ear. The electrode pair with the lowest, the intermediate, and the highest supramaximal stimulating current based on first response (T1) in TOF was found in each patient. A possible response from direct muscle stimulation was evaluated during complete vecuronium block. In 12 patients, supramaximal stimulation was established using a stimulation sequence different from the one used in the first part of the study. RESULTS: The best positions for the stimulating electrodes were either with both electrodes just lateral to the eye, or with one electrode lateral to the eye and one in front of the ear. In most patients, supramaximal stimulation was obtained at these positions at 20-60 mA. However, in 10-21% of the patients, supramaximal stimulation could not be obtained. During complete block, 1-4 responses with a twitch height of 3-11% were recorded in 80% of the patients. CONCLUSION: The best placements of the stimulation electrodes are either just lateral to the eye or along the zygomatic arch. However, supramaximal stimulation may often not be obtainable, and activation of other facial muscles may be a confounding factor that may impede correct evaluation of the degree of neuromuscular block.

Adult↗
PubMed2002

Acceleromyography of the orbicularis oculi muscle II: comparing the orbicularis oculi and adductor pollicis muscles.

BACKGROUND: The orbicularis oculi (OO) muscle has been recommended for neuromuscular monitoring when the adductor pollicis (AP) muscle is not available. We investigated whether neuromuscular block could be measured reliably from the orbital part of the OO muscle by the use of acceleromyography. METHODS: During propofol, fentanyl, and alfentanil anaesthesia two TOF-Guards (Organon Teknika NV, Boxtel, the Netherlands) with acceleration transducers placed on the distal phalanx of the thumb and over the middle of the eyebrow, respectively, were used to measure neuromuscular block simultaneously in 23 patients during vecuronium-induced and neostigmine-antagonized neuromuscular block. For both muscles, the simultaneously recorded first response (T1) in the train-of-four (TOF) and TOF-ratio were measured both during onset and recovery of the block. Furthermore, both the AP muscle T1 and TOF-ratio responses were plotted against 10% intervals of the OO muscle responses during onset and recovery, respectively. RESULTS: The orbicularis oculi muscle had a shorter latency and a faster recovery to TOF-ratio 0.80 compared with the AP muscle. During onset and recovery, pronounced variations of the AP muscle T1 and TOF-ratio responses were observed when compared with the OO muscle. CONCLUSION: A significant clinical disagreement exists between the degree of paralysis measured at the OO and the AP muscles. It is impossible to obtain a reasonable estimate of the degree of block at the AP muscle when the block is measured from the OO muscle with acceleromyography. If used, there is substantial risk of overlooking a residual block, and adequate recovery of the block should be confirmed by a final AP muscle measurement.

Adult↗
PubMed2002

Mortality among anesthesiologists in Denmark, 1973-95.

BACKGROUND: Preliminary data from Sweden indicating that anesthesiologists have a high mortality risk has caused a lot of concern in Denmark. The aim of this study therefore was to compare mortality between consultant anesthesiologists and other consultants in Denmark. METHODS: A historical prospective cohort study based on the membership register of the Danish Medical Association from 1973 to 1992. The study population consisted of 6854 consultants who were members of the Association of Medical Specialists, 406 of whom were anesthesiologists. The all-cause mortality between the two groups was compared during the period 1972-95 using Cox's proportional hazard regression model. RESULTS: The study covered approximately 86000 person-years. A total of 1205 deaths occurred within the period studied, 41 of whom were anesthesiologists. The relative risk for all-cause mortality among the anesthesiologists compared with all the other consultants was 1.0 (95% confidence limit: 0.7-1.4). CONCLUSION: In Denmark there is no evidence of a high mortality risk in consultant anesthesiologists compared with other consultants.

Adult↗
PubMed2002

Rapid simultaneous genotyping of the frequent butyrylcholinesterase variants Asp70Gly and Ala539Thr with fluorescent hybridization probes.

BACKGROUND: The clinically important variants of butyrylcholinesterase (BChE) are the A- (Asp70Gly) and K-variants (Ala539Thr), which are common among Caucasians. These variants are associated with abnormal drug metabolism during anaesthesia, which leads to a prolonged neuromuscular block following administration of the neuromuscular blocking agents, mivacurium and succinylcholine. In addition, the K-variant has been proposed to be associated with Alzheimer's disease together with apolipoprotein E epsilon4. To facilitate diagnostics, we set out to establish a rapid and simple method for simultaneous genotyping of the A- and K-variants. METHODS: Using the LightCycler, a rapid-cycle duplex PCR is combined with generation of allele-specific fluorescent probe melting profiles. This allows simultaneous detection of both of the mutations in the BChE gene. The results were compared with direct sequencing and phenotyping results. RESULTS: Samples from 80 subjects were genotyped. The genotypes determined using the LightCycler were identical to those obtained by direct sequencing of conventional polymerase chain reaction products and was more accurate than phenotyping based on biochemical assays. CONCLUSIONS: A high-speed and easy to perform mutation detection assay has been established for the two most common mutations, Asp70Gly and Ala539Thr, in BChE, using the LightCycler technology and melting curves.

Adult↗
PubMed2002

Remifentanil vs. alfentanil for direct laryngoscopy: a randomized study comparing two total intravenous anaesthesia techniques. TIVA for direct laryngoscopy.

The ideal anaesthesia for direct laryngoscopy is profound and yet brief. The present study sought to determine whether a new anaesthetic technique based on infusion of the ultra short-acting opioid remifentanil was superior to our routine alfentanil multiple-dose technique in terms of haemodynamic stability, stress responses and recovery. A total of 58 patients were randomized to receive propofol and either remifentanil or alfentanil as part of a total intravenous anaesthesia. In the remifentanil group, systolic blood pressure during anaesthesia remained significantly lower than baseline values, while it increased significantly in the alfentanil group. None of the patients receiving remifentanil showed stress responses (hypertension, tachycardia, somatic or autonomic responses), compared to 22 patients (79%) in the alfentanil group (P < 0.0001). In the remifentanil group, hypotension or bradycardia requiring intervention arose in 5 (18%) and 3 patients (11%); neither response was seen in the alfentanil group. The period from the end of propofol infusion until extubation was 5 min longer in the remifentanil group (P < 0.0001), whereas the time from extubation until discharge was similar in the two groups. Thus, neither technique showed sufficient haemodynamic stability, and further studies are needed to determine optimal dosages of propofol and opioid.

Adolescent↗
PubMed2001

[Research in Danish departments of anesthesiology at the turn of the century. A bibliometric analysis].

INTRODUCTION: This investigation was based on the surmise that the scientific activity in the specialty of anaesthesiology and intensive care medicine in Denmark is declining. MATERIAL AND METHODS: A quantitative and qualitative analysis of the development in Danish anaesthesiological research during the seven-year period of 1992-1998 was performed with bibliometrical methods and a count of the PhD and doctoral theses produced by Danish anaesthesiologists during that period. RESULTS: In the period investigated, a total of 906 scientific articles were published, of which 749 (83%) originated from university hospitals. Total production decreased by 15% between the two-year periods of 1992-1993 and 1997-1998, whereas the output from university hospitals alone decreased by 10%. The number of scientific publications per anaesthesiologist decreased by 34%, corresponding to 6.7% per year. The quality of the research published, as examined by the cumulative and average impact, showed a slight increase. The number of PhD and doctoral theses per year showed no change. DISCUSSION: Research activity in Danish anaesthesiology is declining, and the specialty seems to be losing scientific ground, both nationally and internationally.

Academic Dissertations as Topic↗
PubMed2001

Response to mivacurium in a patient compound heterozygous for a novel and a known silent mutation in the butyrylcholinesterase gene: genotyping by sequencing.

BACKGROUND: Patients who are homozygous for the atypical mutation, compound heterozygous for atypical and silent mutations, or homozygous for silent mutations (SS) respond to mivacurium with extensively prolonged neuromuscular block. Although important, exact phenotyping of these patients is difficult. This article presents the pharmacodynamics and pharmacokinetics of a normal dose of mivacurium in a patient with phenotype SS, including a pedigree analysis and delineation of the molecular genetic method used to identify the genotype. METHODS: The neuromuscular block following administration of mivacurium, at a dose of 0.14 mg/kg, was monitored in a 30-yr-old healthy man with use of a mechanosensor and mechanomyography, and times to different levels of recovery were measured. Venous samples for determination of the mivacurium isomers were collected during the interval 134-494 min after administration of mivacurium, and the terminal half-lives were calculated. Butyrylcholinesterase activity, phenotype, and genotype were determined for both the patient and the family. Complete nucleotide sequencing was used to identify the genotype. RESULTS: A train-of-four ratio of 0.75 was reached 469 min after the injection of mivacurium. The terminal elimination half-lives of the mivacurium isomers, cis-trans and trans-trans, were 90 min. Complete nucleotide sequencing revealed two point mutations, the known silent variant S7 and a previously undescribed mutation of amino acid residue 170 introducing a stop codon. CONCLUSIONS: The patient was compound heterozygous for silent mutations in the butyrylcholinesterase gene. The response to mivacurium was an extensively prolonged duration of action. Identification of the rare silent mutations presupposes access to modern molecular genetic methods such as complete nucleotide sequencing.

Adult↗
PubMed2001

Neuromuscular monitoring.

This review summarizes recent reports on the techniques and the use of methods for monitoring neuromuscular function during anaesthesia. The latest news on the use of acceleromyography in the face and hand, on laryngeal and diaphragmal surface electromyography, on acoustic myography, on evaluation of intense neuromuscular block, and on postoperative residual curarization is presented and discussed. It is concluded that available evidence suggests that more attention should be paid by the anaesthetist to the problems of residual curarization and hence to proper monitoring of neuromuscular function using objective methods.

Journal Article↗
PubMed2000

Pharmacokinetic studies of neuromuscular blocking agents: good clinical research practice (GCRP).

In September 1997, an international consensus conference on standardization of studies of neuromuscular blocking agents was held in Copenhagen, Denmark. Based on the conference, a set of guidelines for good clinical research practice (GCRP) in pharmacokinetic studies of neuromuscular blocking agents is presented. Guidelines include: design of the study; relevant patient groups to investigate; test drug administration, sampling and analysis; pharmacokinetic analysis; pharmacokinetic/pharmacodynamic modeling; population pharmacokinetics; statistics; and presentation of pharmacokinetic data. The guidelines are intended to aid those working in this research area; it is hoped that they will assist researchers, editors of scientific papers, and pharmaceutical companies in improving the quality of pharmacokinetic studies.

Body Temperature↗