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Biomedical subjects

M Blobner

Publications and source records attributed to M Blobner.

At least 19 recordsLinked to original sources

Incidence and duration of residual paralysis at the end of surgery after multiple administrations of cisatracurium and rocuronium.

In a randomised, controlled, double-blind, multicentre trial in 338 patients, we assessed the incidence of residual paralysis following administration of cisatracurium or rocuronium. The incidence at the end of surgery was significantly lower in patients treated with rocuronium (62 of 142 patients, 44%) than in those given cisatracurium (99 of 175 patients, 57%) (p < 0.05). In contrast, with rocuronium the mean (SD) time between skin closure and extubation was 28 (28) min vs 18 (19) min for cisatracurium, and the duration 0.9 (time from administration of last top-up dose to recovery of the train-of-four ratio to 0.9) was significantly longer and more variable for rocuronium than for cisatracurium. Thus, after repeated administration, the duration and variability of duration of action are greater with rocuronium compared with cisatracurium. These pharmacodynamic differences do not necessarily translate into a higher incidence of residual paralysis, because clinicians compensate for the longer duration of action and variability of rocuronium by terminating administration of the neuromuscular blocking earlier.

Androstanols↗

Onset properties of mivacurium measured by mechanomyography depend on the twitch height of the adductor pollicis muscle.

INTRODUCTION: The influence of the twitch height of the adductor pollicis muscle during baseline measurements on the pharmacodynamic parameters of mivacurium was prospectively evaluated. PATIENTS AND METHODS: Fifty adult patients were anaesthetized with propofol and alfentanil. Neuromuscular function was monitored mechanomyographically by measuring the force of the adductor pollicis muscle following stimulation of the ulnar nerve. Following a stabilization period of 20 min, the individual twitch height of the adductor pollicis muscle was determined before a single bolus of mivacurium (75 microg kg-1) was administered. Patients were divided into two groups. The data of patients whose thumb adduction force was below the median value of all patients were the 'low force' group (9.1 +/- 1.4 N) and the data of all other patients were the 'high force' group (13.7 +/- 1.8 N). RESULTS: In the 'high force' group, maximum neuromuscular blockade of mivacurium was deeper (0.97 +/- 0.05 vs. 0.93 +/- 0.06; P < 0.05) and onset faster (2.9 +/- 1.1 min vs. 4.0 +/- 1.2 min; P < 0.05). Neuromuscular recovery did not differ between the groups. CONCLUSION: The different onset speeds reflect either different sensitivity to neuromuscular blocking agents with respect to patients' muscle power or a problem of the mechanomyographic measuring technique.

Adult↗

[Muscle relaxants in Germany 2005: a comparison of application customs in hospitals and private practices].

Aim of this study was to evaluate application customs of muscles relaxants in hospitals compared to their use in private practice. Of the 3,260 questionnaires sent-out, 66.9% could be analyzed. Of these 54% were from anesthetists in private practice, 41% from heads of hospital anesthesia departments and 5% from heads of level one hospital anesthesia departments. The first difference between private practices and hospitals was the number of available muscle relaxants: 87% of private practices use 1-3 relaxants, whereas 79% of hospitals use 3-5. Another apparent difference was the relationship between general anesthesia and the number of intubations: 60% of private practices have over 80% of general anesthesia cases, but only 50% of these patients are intubated. On the contrary, two thirds of the hospitals have 50-80% general anesthesia cases and 60-70% of patients are intubated. The main wish for an ideal muscle relaxant was independent of private practice or hospital, short onset time, followed by fast recovery. In accordance 74% of anesthetists in hospitals and 72% of anesthetists in private practice voiced the wish for a non-depolarizing succinylcholine substitute. The results of this nationwide survey suggest that time pressure in combination with an increased specialization of anesthetists in private practice are the main factors for availability and use of muscle relaxants in routine anesthesia.

Anesthesia↗

[Transport of blood gas samples: is the pneumatic tube system safe?].

BACKGROUND: Transport of blood gas samples via a pneumatic tube system and subsequent analysis in the central laboratory can reduce costs and errors compared to on-site testing in the operating theatre or the intensive care unit. In this study, a modern pneumatic tube transport system was tested for its usability for this purpose. METHODS: A total of 4 consecutive blood gas samples were obtained intraoperatively from 54 different patients and sent to the central laboratory. Of these, 3 samples were transferred using the pneumatic tube system but by different methods and 1 sample was transported personally which served as a reference. The results of sample analysis concerning blood gases, electrolytes and haemoglobin were compared and examined for differences. RESULTS: No statistically significant differences could be determined between the different modes of transportation. CONCLUSION: Transport of samples for blood gas analysis via a modern pneumatic tube system is safe when samples are correctly prepared.

Analysis of Variance↗

Sevoflurane and propofol influence the expression of apoptosis-regulating proteins after cerebral ischaemia and reperfusion in rats.

BACKGROUND AND OBJECTIVE: Sevoflurane and propofol reduce the extent of necrosis and improve neurological outcome in rodent models of cerebral ischaemia and reperfusion. However, the effects of these anaesthetics on programmed cell death (apoptosis) are unclear. The present study investigates whether sevoflurane and propofol affect the expression of apoptosis-regulating proteins after cerebral ischaemia in rats. METHODS: Thirty-two fasted male Sprague-Dawley rats were tracheally intubated and the lungs were ventilated (isoflurane and N2O/O2 anaesthesia). After surgical preparation, the animals were randomly assigned to one of the following groups: control (n = 8): fentanyl intravenous (10 microg kg(-1) bolus and 25 microg kg(-1) h(-1) infusion) with N2O/O2; sevoflurane (n = 8): 2.0% sevoflurane (end-tidal concentration) and O2/air; propofol (n = 8): 0.8-1.0 mg kg(-1) min(-1) propofol intravenous and O2/air; sham-operated (n = 8): 25 microg kg(-1) h(-1) fentanyl intravenous and N2O/O2, no cerebral ischaemia. Ischaemia (30 min) was induced by unilateral common carotid artery occlusion plus haemorrhagic hypotension to a mean arterial pressure of 30-35 mmHg. Four hours after cerebral ischaemia the brains were removed and the expression of apoptosis-regulating proteins (Bax, Bcl-2, p53, Mdm-2) was determined using immunofluorescence and Western-blot analyses. RESULTS: The expression of the pro-apoptotic protein Bax was greater in control animals than in sevoflurane or propofol anaesthetized rats and than in sham-operated animals. The concentrations of Bcl-2, p53 and Mdm-2 were not changed 4 h after cerebral ischaemia. CONCLUSIONS: In addition to the anti-necrotic effects of sevoflurane and propofol, these anaesthetics also reduce the concentration of the apoptosis-inducing protein Bax as early as 4 h after ischaemia.

Anesthetics, Inhalation↗

[The use of muscle relaxants for routine induction of anesthesia in Germany].

The aim of this study was to evaluate the use of muscle relaxants during induction of anesthesia in patients without risk of aspiration of stomach contents. Of the 2,996 questionnaires sent out, 2,054 (68.6%) could be analysed and the results show that succinylcholine is used regularly in 13.6% of anesthesia departments. The next most commonly used muscle relaxants are atracurium, vecuronium and mivacurium, followed by cis-atracrium, rocuronium and pancuronium. Alcuronium is the least frequently used muscle relaxant. During induction of an elective anesthesia procedure, a priming technique is used by 19% of anesthesiologists, 22% utilize precurarization, and a timing technique is performed in 7.1%. The use of muscle relaxants for on-going relaxation follows the same pattern as for induction of neuromuscular blockade and succinylcholine is used in 1.4% if further relaxation is needed. The desire for specific qualities of muscle relaxants is correlated with higher use of the specific substance: short onset time for rocuronium, good controllability with mivacurium, no side-effects with cisatracurium and economical aspects with alcuronium. Of the participants 76.6% voiced the desire for a non-depolarizing replacement for succinylcholine.Private practices use mivacurium more often than hospitals, level one hospitals use rocuronium and cisatracurium more often. This survey could not show a definite standard of use in terms of muscle relaxants for an elective case.Precurarization, priming and timing are used frequently in patients not at risk of aspiration. This should be reduced by on-going teaching.

Anesthesia↗

[Application of muscle relaxants in Germany. A survey of German anaesthesia departments].

AIM: The aim of this study was to evaluate the use and application of muscle relaxants and neuromuscular monitoring in Germany. METHODS: A total of 2,996 questionnaires were sent out to the heads of German anaesthesia departments and private anaesthesia practices. The questions covered frequency of muscle relaxants used,how they were used, and neuromuscular monitoring. Influences on the way muscle relaxants were used could be derived from the desire for specific properties of a muscle relaxant, the desire for different monitoring conditions and from the size of the institution. We correlated these features with application practice using logistic regression analyses. RESULTS: Of the 2,996 questionnaires 2,058 could be analysed (68.6%). Amongst those were 102 level one hospitals (5%) and 903 private practices (44%). The replies from 350 (17%) departments were based on surveyed data, 1,613 (78.5%) were based on estimations. The desire for certain properties of muscle relaxants correlated with the use in practice, as were the desire for a non-depolarizing replacement for succinylcholine, the size of the department and the frequency of use of neuromuscular monitoring. Over 50% of all German anaesthesia departments limited the use of muscle relaxants to three. The use of laryngeal masks reduced the use of muscle relaxants. CONCLUSIONS: The survey regarding use of muscle relaxants in Germany could for the first time give an overview on the use of anaesthesia-specific substances in Germany. From the different frequencies of use and use modalities,conclusions could be drawn towards a standard of application for the year 2000. Changes in this standard would raise the need for further trend surveys. The methods of statistical analysis and survey evaluation can be used as a base for further surveys.

Anesthesia↗

[Application of muscle relaxants for rapid-sequence induction of anaesthesia].

The present study evaluates the use of muscle relaxants for rapid-sequence induction (RSI) and different application techniques (pre-curarisation, priming, timing) as a part of a nationwide survey in Germany. In 86.8% of anaesthesia departments succinylcholine is used for RSI and an average of 56.5% of respondents used only succinylcholine for RSI. Of all non-depolarising muscle relaxants rocuronium is the most frequently used alternative. Of the anaesthesia departments 2.6% use rocuronium regularly in patients with increased risk for aspiration of stomach contents; level one centres significantly more than others, 12.9% answered that pre-curarisation techniques were never used, whereas 45.6% use non-depolarising neuromuscular blocking drugs before giving succinylcholine in 80-100% of cases. Priming is not used by 64.4% of respondents, as opposed to 9.8% who utilise this technique regularly. The statements regarding timing are 71.1% and 5.4%, respectively. Alcuronium is used for RSI in departments in which the financial aspect is the primary decision criteria. Despite ist known side-effects and the on-going discussion over the past years, succinylcholine is still the most frequently used muscle relaxants for RSI. Priming is often declined by anaesthetists in Germany, most probably due to the absence of clear advantages and the possibility of severe complications. It is the opinion of the authors that timing but also drugs with a slow onset (e.g., alcuronium and Pancuronium) are obsolete in the context of RSI.

Alcuronium↗

[The use of neuromuscular monitoring in Germany].

AIM: As there are no reliable epidemiological data for the use of muscle relaxants in Germany,we conducted a mailing study. The aim of the study was to compare the use of muscle relaxants between German anaesthesia departments. In the present part of the presentation we focused on neuromuscular monitoring (NMM) and management of residual paralysis. METHODS: A total number of 2,996 questionnaires were sent to all registered anaesthesiological facilities in Germany and the return was 68.6% (2054 questionnaires). RESULTS: In 574 of the returned questionnaires (28%) the regular use of NMM was confirmed. Intraoperative monitoring of neuromuscular block and assessment of neuromuscular recovery were the most frequent applications of NMM, i.e. 25% and 18% of returned questionnaires, respectively. Clinical signs, however, are still the most popular way to estimate the degree of neuromuscular blockade. Moreover, routine reversal at the end of surgery with a neostigmin/atropine mixture was not practiced in 75% of the anaesthesia departments. CONCLUSIONS: This survey revealed that NMM is still very rarely used in daily clinical practice. Especially the seldom use of NMM to assess residual paralysis has to be improved.

Anesthesiology↗

Effects of xenon on mesenteric blood flow.

BACKGROUND AND OBJECTIVE: The effects of xenon on mesenteric vascular resistance have not been investigated. Because human beings anaesthetized with xenon show good cardiovascular stability, we believed that the agent would have little or no effect on vascular resistance in the splanchnic bed. We determined the effects of different inhaled xenon concentrations on mesenteric blood flow and mesenteric oxygen consumption in pigs sedated with intravenous propofol. METHODS: Twenty-three minipigs were instrumented with transit time flow probes around the pulmonary and superior mesenteric arteries as well as with pulmonary artery and portal venous catheters. A 14 h recovery was allowed followed by recordings of baseline values. Xenon was then randomly administered in 0.30, 0.50, and 0.70 end-tidal fractions. RESULTS: The administration of xenon resulted in an 8% (not dose dependent) decrease in mean arterial pressure (from 99 +/- 15 to 91 +/- 19 mmHg; P < 0.05), a 20% decrease in calculated systemic oxygen consumption (from 0.23 +/- 0.07 to 0.19 +/- 0.04L min(-1); P < 0.01), a 20% reduction in mesenteric oxygen delivery (from 41 +/- 12 to 33 +/- 11 mL min; P < 0.001), a 37% reduction in mesentericmetabolic rate of oxygen (from 11.3 +/- 3.6 to 7.1 +/- 3.2 mL min(-1); P < 0.01) and an 8% decrease in mesenteric artery blood flow (0.22 +/- 0.07 to 0.20 +/- 0.07 L min(-1); P < 0.05) in a dose-dependent fashion. Heart rate, cardiac output, systemic vascular resistance, mesenteric vascular resistance, mesenteric oxygen extraction fraction and portal lactate concentration were not significantly altered by xenon. CONCLUSIONS: Xenon inhalation in the propofol-sedated pig had no measurable effects on mesenteric vascular resistance. This finding may partly explain the well-known cardiovascular stability observed in patients anaesthetized with xenon. Although mesenteric artery blood flow and mesenteric oxygen delivery decreased during xenon administration, unchanged mesenteric oxygen extraction fraction and portal lactate suggest that metabolic regulation of the splanchnic circulation remained unaltered.

Anesthetics, Inhalation↗

[Anaesthesia today].

Anaesthesia today is a cross-over of all medical sub-specialities, based on a stable scientific fundament and a high margin of safety. Anaesthetic techniques are sophisticated and enable a differentiated treatment of pre-, intra- and post-operative medical demands. The physician-patient-relationship and the patients' satisfaction are main aspects of peri-operative care by anaesthetists even in the area of conflict by economic pressure. Nonetheless, the credit to anaesthetists given by physicians and also by the general public is inadequate resulting in difficulties to recruit a sufficient percentage of the decreasing number of aspiring physicians. This could be prevented by an improved medical school and training. Anaesthesiologists in science address either fundamental questions as to mechanisms of anaesthesia and epidemiological aspects of peri-operative medicine.

Anesthesia↗

[The time-course of action of rapacuronium and mivacurium after early reversal following equally lasting relaxation].

This study was designed to compare the time course of action and the safety profile of Rapacuronium and Mivacurium in day case dental surgery. After Ethics Committee approval 61 healthy adult patients, scheduled for dental day case surgery, were randomised in an assessor-blinded manner to receive either 1.5 mg/kg Rapacuronium with and without 0.05 neostigmine 5 min later (19 patients each) or a total of 0.25 mg/kg Mivacurium (n = 16). Anaesthesia was induced using Propofol 2 - 5.1 mg/kg and Remifentanil 24 - 73 mcg/kg/h and maintained with Desflurane in N2O/O2 (2/1). Endotracheal intubation was performed when maximum blockade was achieved and scored by a blinded intubator. Neuromuscular block was monitored using the train-of-four response to supramaximal stimuli at the ulnar nerve every 15 seconds using acceleromyography (TOF Watch SX). Onset time, clinical duration (reappearance of the third twitch of a TOF-stimulation) and recovery to T4/T1 > 0.9 were recorded. Speed of recovery was evaluated by the time difference between reappearance of the third twitch and T4/T1 > 0.9. The intubating conditions at the time of maximum block revealed no statistically significant differences between the three groups. Changes in blood pressure, heart rate and airway pressure were not significant. Onset time in subjects who received Rapacuronium (99 +/- 29 s) was faster compared to the onset time in those who received Mivacurium (157 +/- 36 s). Also clinical duration was significantly shorter following Rapacuronium without reversal (12 +/- 4 min) as well as with reversal (9 +/- 1 min) compared with Mivacurium (21 +/- 5 min)). Patients treated with Rapacuronium and reversal recovered faster (14 +/- 8 min)) compared to the other two groups (Mivacurium: 20 +/- 6 min, Rapacuronium without reversal: 31 +/- 9 min). The fraction of clinical duration of the total duration was highest following Mivacurium (51 %) when compared with Rapacuronium/Neostigmine (43 %) and Rapacuronium (28 %).

Adolescent↗

[Anesthesia in patients with myasthenia gravis].

Myasthenia gravis is a chronic autoimmune disease characterised by progressive weakness and easy fatigability of voluntary skeletal muscles. These symptoms are related to a decrease in the number of functional acetylcholine receptors, impaired neuromuscular transmission, and a broadened neuromuscular cleft. Symptomatic treatment is based on anticholinesterases in order to increase the synaptic dwell of acetylcholine. Immune therapy includes immune suppressive drugs, plasma exchange, immunoglobulins, and thymectomy. Anticholinesterase therapy should be continued in the current mode until anaesthesia. Regional anaesthesia should be preferred. Although sensitivity to non-depolarising neuromuscular blocking agents is increased, muscle relaxants can be administered during general anaesthesia as long as neuromuscular monitoring assesses their individual effect. Due to the individual variability in the response to muscle relaxants, accurate titration in combination with pre- and intraoperative neuromuscular monitoring is essential for myasthenic patients. Postoperatively, intensive care observation is mandatory including neuromuscular monitoring.

Anesthesia↗

Inflammatory liver disease shortens atracurium-induced neuromuscular blockade in rats.

BACKGROUND: and objective Inflammatory liver dysfunction in rats leads to a prolonged vecuronium-induced neuromuscular blockade due to insufficient metabolism. A coexisting resistance against the drug partly counteracts this prolongation. The present study investigates the pharmacodynamics of atracurium whose metabolism does not depend on liver function. METHODS: Male Sprague-Dawley rats (n=14; 290 +/- 30 g) were randomly allocated to either a group in which liver inflammation was induced by intravenous injection of 60 mg kg(-1) heat-killed Corynebacterium parvum or to a control group. On day 5 after injection, liver function was assessed using the aminopyrine breath test. Under propofol anaesthesia, duration of action of atracurium (4.8 mg kg(-1)) was measured by evoked mechanomyography (stimulation of the sciatic nerve; contraction of the gastrocnemius muscle). Nitric oxide concentrations, as variables for the severity of the inflammation, were assessed by measurement of nitrite/nitrate plasma concentrations. RESULTS: In C. parvum-injected rats, nitrite/nitrate plasma concentrations were increased (972 +/- 597 vs. 25 +/- 7 micromol L(-1)), the aminopyrine turnover was depressed (1.7 +/- 0.4% vs. 3.5 +/- 0.5%), and the atracurium-induced neuromuscular blockade was shortened (372 +/- 128 s vs. 1081 +/- 234 s). CONCLUSIONS: A systemic inflammatory response syndrome with liver dysfunction results in decreased sensitivity to atracurium. Further investigations are needed regarding a possible up-regulation of acetylcholine receptors or an increased protein binding of atracurium during sepsis to clarify reasons behind this phenomenon.

Alanine Transaminase↗

Effects of xenon on cerebral blood flow and cerebral glucose utilization in rats.

BACKGROUND: The effects of xenon inhalation on mean and local cerebral blood flow (CBF) and mean and local cerebral glucose utilization (CGU) were investigated using iodo-[14C]antipyrine and [14C]deoxyglucose autoradiography. METHODS: Rats were randomly assigned to the following groups: conscious controls (n = 12); 30% (n = 12) or 70% xenon (n = 12) for 45 min for the measurement of local CBF and CGU; or 70% xenon for 2 min (n = 6) or 5 min (n = 6) for the measurement of local CBF only. RESULTS: Compared with conscious controls, steady state inhalation of 30 or 70% xenon did not result in changes of either local or mean CBF. However, mean CBF increased by 48 and 37% after 2 and 5 min of 70% xenon short inhalation, which was entirely caused by an increased local CBF in cortical brain regions. Mean CGU determined during steady state 30 or 70% xenon inhalation remained unchanged, although local CGU decreased in 7 (30% xenon) and 18 (70% xenon) of the 40 examined brain regions. The correlation between CBF and CGU in 40 local brain structures was maintained during steady state inhalation of both 30 and 70% xenon inhalation, although at an increased slope at 70% xenon. CONCLUSION: Effects of 70% xenon inhalation on CBF in rats are time-dependent. During steady state xenon inhalation (45 min), mean values of CBF and CGU do not differ from control values, and the relation of regional CBF to CGU is maintained, although reset at a higher level.

Anesthetics, Inhalation↗

Effects of carbon dioxide pneumoperitoneum on cerebral hemodynamics in pigs.

Previous studies have shown that laparoscopic interventions are associated with increases in intracranial pressure. However, the consequences on cerebral blood flow (CBF) are unknown. This study investigates the effects of carbon dioxide (CO2) pneumoperitoneum on CBF in pigs. Ten pigs (weight, 20-26 kg) were anesthetized with 1.4% isoflurane and fentanyl (1 microg/kg per minute). Mechanical ventilation (fraction of inspired oxygen = 0.4) was set to maintain normocapnia (end-tidal CO2 tension = 35 mm Hg). Arterial and central venous catheters were placed for measurement of mean arterial blood pressure and central venous pressure. Bilateral internal carotid artery blood flow was measured using two transient time flow probes placed around both carotid arteries (with ligated external carotid arteries). Cortical and subcortical cerebral blood flow was measured using laser Doppler flowmetry. Sagittal sinus pressure was measured via a superior sagittal sinus catheter. After baseline measurements, the peritoneal cavity of the animals was insufflated with CO2 to achieve an intraabdominal pressure of 12-mm Hg. After 10 minutes of stable CO2, pneumoperitoneum measurements were repeated. Increases in central venous pressure (6.3 +/- 2.1 to 11.1 +/- 3.0 mm Hg) and sagittal sinus pressure (8.0 +/- 2.8 to 11.9 +/- 3.0 mm Hg) were noted during CO2 pneumoperitoneum (P < .05). Bilateral internal carotid artery blood flow (46.0 +/- 7.4 vs 47.7 +/- 7.1 mL/100g per minute), cortical CBF (263 +/- 115 vs 259 +/- 158 tissue perfusion units), and subcortical CBF (131 +/- 145 vs 133 +/- 149 tissue perfusion units) did not change during CO2 pneumoperitoneum. The current data show that CO2 pneumoperitoneum increases sagittal sinus pressure without changing CBF. Increases in sagittal sinus pressure are likely related to decreases in cerebral venous drainage caused by increases in intraabdominal pressure.

Abdomen↗

Sensitive chemiluminescence immunoassay for the determination of rat serum alpha1-acid glycoprotein.

We present the establishment of a sensitive immunoassay for the determination of alpha1-acid glycoprotein (orosomucoid, AGP) in rat serum. The assay is based upon antigen capture by surface-immobilized specific polyclonal rabbit anti-AGP antibodies with biotinylated rat AGP (rAGP) as the tracer, and formatted as competitive enzyme immunoassay. Signaling is performed by streptavidin-conjugated horseradish peroxidase. Enzyme activity is quantified by an enhanced chemiluminometric method, allowing the sensitive detection of rAGP serum levels in small sample volumes.

Animals↗