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Biomedical subjects

G Wiesner

Publications and source records attributed to G Wiesner.

At least 37 records · Page 2Linked to original sources
PubMed1999

Genetic damage in operating room personnel exposed to isoflurane and nitrous oxide.

OBJECTIVES: To evaluate genetic damage as the frequency of sister chromatid exchanges and micronuclei in lymphocytes of peripheral blood of operating room personnel exposed to waste anaesthetic gases. METHODS: Occupational exposure was measured with a direct reading instrument. Venous blood samples were drawn from 10 non-smokers working in the operating room and 10 non-smoking controls (matched by age, sex, and smoking habits). Lymphocytes were cultured separately over 72 hours for each assay with standard protocols. At the end of the culture time, the cells were harvested, stained, and coded for blind scoring. The exchanges of DNA material were evaluated by counting the number of sister chromatid exchanges in 30 metaphases per probe or by counting the frequency of micronuclei in 2000 binucleated cells. Also, the mitotic and proliferative indices were measured. RESULTS: The operating room personnel at the hospital were exposed to an 8 hour time weighted average of 12.8 ppm nitrous oxide and 5.3 ppm isoflurane. The mean (SD) frequency of sister chromatid exchanges was significantly higher (10.2 (1.9) v 7.4 (2.4)) in exposed workers than controls (p = 0.036) the proportion of micronuclei (micronuclei/500 binucleated cells) was also higher (8.7 (2.9) v 6.8 (2.5)), but was not significant (p = 0.10). CONCLUSION: Exposure even to trace concentrations of waste anaesthetic gases may cause dose-dependent genetic damage. Concerning the micronuclei test, no clastogenic potential could be detected after average chronic exposure to waste anaesthetic gas. However, an increased frequency of sister chromatid exchanges in human lymphocytes could be detected. Although the measured differences were low, they were comparable with smoking 11-20 cigarettes a day. Due to these findings, the increased proportion of micronuclei and rates of sister chromatid exchanges may be relevant long term and need further investigation.

Adult↗
PubMed1999

Leptin is released from the human brain: influence of adiposity and gender.

Leptin, a 16-kDa circulating protein primarily derived from adipocytes, is an important factor in the regulation of appetite and energy expenditure. Using simultaneous arterio-venous blood sampling, several organs were assessed with regard to their individual roles in leptin metabolism in healthy male and female subjects constituting a range of body mass indices. Plasma leptin levels were unchanged after passage through the hepatosplanchnic and forearm circulations. In contrast, concentrations in the renal vein were consistently lower than those in the renal artery (-15%; P<0.005), indicating net extraction, whereas the brain was observed to be a net leptin releaser. Concentrations in the internal jugular vein were significantly higher than arterial levels in lean females (change, 3.0+/-1.2 ng/mL; P<0.02) and in obese males (body mass index, >28 kg/m2), but not lean (change, 2.3+/-2.3 vs. 0.1+/-0.1 ng/mL, respectively; P<0.05), indicating a probable influence of both gender and adiposity on brain leptin release. An attempt to grossly localize the site of brain release by using cerebral venous scans to distinguish between jugular venous drainage from cortical and subcortical brain areas revealed no region-specific secretion. These data raise the possibility that the brain is a nonadipose source of leptin. In addition, the higher level of brain release observed in females may contribute to the well documented gender differences in overall plasma leptin levels.

Adipose Tissue↗
PubMed1999

[Incidence of myocardial infarct in Germany: prevalence, incidence trends, East-West comparison].

The German National Health Interview and Examination Survey, as a descriptive cross-sectional study, allows the recording of post-myocardial infarct cases, e.g. the number (prevalence) of survivors after an infarct has occurred (non-lethal myocardial infarcts). The 18 to 79 year old residential population in Germany had a lifetime prevalence of 2.45% for conditions after a heart attack. The age-specific lifetime prevalence values increase with increasing age for both men and women. Between the ages of 30 and 59 there are more than 4 male heart attack victims for every woman; between the ages of 60 and 79 this relation is only 1 to 1.5. The 30-< 80 year old population in Germany has around 1,450,000 post-myocardial infarct cases (heart attack victims). There are about 100,000 male post-myocardial infarct cases among relatively young adults between 30 and 49 years of age. There were hardly any cases in the female population in this age group. In regard to post-myocardial infarcts there were no significant morbidity differences between the eastern and western German states in 1997/98. A comparison of the lifetime prevalence rates between 1997/98 and 1990/92 shows the following trend: the number of post-myocardial infarcts in the German population 25-< 70 years old decreased; in Western Germany the lifetime prevalence rates also declined, in Eastern Germany the prevalence rates among both men and women increased in this period of time. In the period 1997/98 there were around 190,000 non-lethal myocardial infarcts in the 18 to 79 year old German population in a full 12 month period (incidence cases of survivors after the occurrence of an acute first and/or acute reinfarcts).

Adolescent↗
PubMed1999

[Stroke: prevalence, incidence, trends, East-West comparison. Initial results of the 1998 Federal Health Survey].

The prevalence of survival after a stroke is dependent on the incidence and the fatality rate, whereby the incidence and the fatality rate are influenced by different factors. A survey can only include the minor cases of post-stroke conditions. The prevalence figures thus only reflect the less serious or rehabilitated strokes. Despite this underrepresentation of strokes in the survey we can observe an underestimation of the stroke problem in Germany. Whereas we previously assumed 440,000 to 500,000 strokes in Germany, the projection from the data of the German National Health Interview and Examination Survey amounted to around 945,000 cases (only strokes with "minor" motor, sensory and cognitive losses and restrictions which allow a participation in the survey). The lifetime prevalence rate of the 18-< 80 year old female population is somewhat higher than the male population of the same age (n.s.). The 50 to < 60 year old men have a relatively high prevalence rate. The corresponding age specific prevalence rates increase with increasing age. There are no significant differences in morbidity between the former East and West German states, the prevalence rates of men are somewhat higher in the East and those of women in the West. We can see the following trends in a comparison of the lifetime prevalence rates between 1997/98 and 1990/92: the number of post-stroke conditions among German men 25-< 70 years old declined significantly, among women they increased slightly (n.s.); the prevalence as a whole also declined significantly among men in western Germany, among women they increased slightly (n.s.) in contrast to former West Germany the prevalence rates among men in eastern Germany increased slightly, among women they were almost cut in half. 32.8% of the population with "minor" post-stroke conditions is characterized by sensory disruptions, 32.1% by impairments when walking, 31.3% by paralyses, 20.5% by speech impairments, 17.1% by cognitive disorders and 3.1% by disturbances of consciousness.

Adolescent↗
PubMed1998

Deletion 10q23.2-q23.33 in a patient with gastrointestinal juvenile polyposis and other features of a Cowden-like syndrome.

A cytogenetically visible interstitial deletion of chromosome band 10q23 was found in a 6-year-old boy with mental retardation, dysmorphic features, and juvenile polyposis coli. In order to map this patient's deletion physically, we performed fluorescence in situ hybridization by using yeast artificial chromosomes (YACs) in the vicinity of the deletion. Five YACs that span an 11-15 cM region within the deletion were identified. This patient's deletion contains the putative locus for Cowden syndrome and a recently discovered candidate tumor suppressor gene (MMAC1 or PTEN) that has been implicated in the progression of a variety of human malignancies. Furthermore, the deletion is near and possibly overlaps a locus associated with juvenile polyposis. The findings in this patient with a constitutional 10q23 deletion raise the issue of whether there are separate genes in this region that are involved in Cowden syndrome, Bannayan-Riley-Ruvalcaba syndrome, juvenile polyposis, and tumor progression, or whether all of these entities could be due to a single gene.

Child↗
PubMed1998

[Occupational exposure and environmental pollution: the role of inhalation anesthetics with special consideration of sevoflurane].

There are a number of assays available to study genetic toxicity of inhalation anaesthetics. Those discussed in this review are the Ames Salmonella mutagenesis test and assays for structural chromosome aberrations, micronuclei (MN) and sister chromatid exchanges (SCEs). None of these assays showed abnormalities induced by volatile inhalation anaesthetics. Only Compound A induced a slight increase in the number of SCEs. However, the implications of this in vitro study are unclear. Results of studies focussing on the effects of long-term occupational exposure to inhalation anaesthetics are controversial. Neither harmfulness nor safety of chronic exposure to low concentrations of inhalation anaesthetics have been proven. Although there is no clear evidence of harmfulness, there is general agreement that occupational exposure should be minimized for precautionary reasons. This particularly applies to N2O. Therefore, occupational exposure standards have been established in many countries, though not yet for sevoflurane and desflurane. In Germany, occupational exposure can be kept below the threshold values, when working in operation theatres with a standard air conditioning system, a high-flow scavenging system, low leakage anaesthesia machines and preventative maintenance of equipment. Under these conditions occupational exposure is low even when using laryngeal mask airways and uncuffed tracheal tubes. Sevoflurane is a halocarbon, but is only partially halogenated and the only halogen it contains is fluorine. Sevoflurane, therefore, appears to have an insignificant effect on ozone depletion and its contribution to the greenhouse effect is negligible.

Anesthesiology↗
PubMed1998

Waste gas exposure during desflurane and isoflurane anaesthesia.

BACKGROUND: Currently, there are no data available concerning the occupational exposure to desflurane during general anaesthesia. This prospective, randomized study reports on occupational exposure to desflurane, compared to isoflurane, in a modern operation theatre (OT). METHODS: The study was performed in an OT equipped with a modern air-conditioning system and with a low-leakage anaesthesia machine connected to a central scavenging system. Trace concentrations of the anaesthetics were measured continuously by means of a photoacoustic infrared spectrometer during general anaesthesia in 30 patients undergoing eye surgery. Values were obtained within the breathing zone of the anaesthetist, the surgeon, the auxiliary nurse and at the mouth of the patient. RESULTS: Desflurane and isoflurane were administered with median (range) endtidal concentrations of 4.7 (3.8-10.3) vol% and 0.9 (0.6-1.4) vol%, respectively. The personnel-related median values of the average trace concentrations of desflurane and isoflurane were 0.5 (0.01-7.5) ppm and 0.2 (0.01-1.6) ppm, respectively. CONCLUSIONS: Occupational exposure to desflurane is low in the environment of a modern OT, even though it has to be administered in approximately 5-fold higher concentrations compared to isoflurane.

Air Conditioning↗
PubMed1998

[Biological monitoring during exposure to the anesthetics isoflurane and sevoflurane].

Exposure to traces of inhaled anaesthetic agents may impair the health of the operating theatre personnel. Although no cause-effect relationship has been found, most public health authorities recommend various occupational exposure standards to minimize possible health risks. If metabolites of the substances are known, biological monitoring is an alternative to the monitoring of the operating theatre's air. The new anaesthetic agent Sevoflurane is considerably more transformed to fluoride than Isoflurane. Concerning fluoride there exist Biological Tolerance Values of 4.0-7.0 mg fluoride (F-) per gram creatinine (Crea). The aim of our study was to compare the fluoride excretion under the occupational exposure to sevoflurane and isoflurane. By the means of a direct-reading instrument trace concentrations of sevoflurane, isoflurane, and nitrous oxide were measured during 40 anaesthetic procedures. Urine samples were collected before (Z1) and after the workshift (Z2), and in the morning of the next day (Z3). The analysis was done by the means of an ionselective electrode. The personnel-related concentrations (median, range) were 0.50 (0.16-7.04) ppm isoflurance and 27.36 (5.87-467.10) ppm nitrous oxide, and 0.79 (0.15-1.95) ppm sevoflurane and 17.74 (2.45-84.20) ppm nitrous oxide. The resulting fluoride values presented at Z1, Z2, and Z3 as median (range) during exposure to isoflurane were 0.15 (0.11-0.53), 0.19 (0.11-0.53), 0.20 (0.11-0.31) mg F-/g Crea, and 0.15 (0.10-0.46), 0.22 (0.13-0.44), 0.23 (0.15-0.69) mg F-/g Crea during exposure to sevoflurance, respectively. The trace concentrations were clearly under 10 ppm for the volatile substances and 100 ppm for nitrous oxide. The values are comparable to data recorded under similar working conditions. The measured fluoride values were low and remained under the legal tolerance values. Under the described conditions potential health risks were low.

Air Pollution, Indoor↗
PubMed1997

[Room air contamination with halothane during pediatric bronchoscopy].

Halothane anesthesia is frequently used for pediatric bronchoscopy. A disadvantage of the equipment used, a rigid bronchoscope together with inhalation anesthesia is the contamination of the working environment. The aim of this study was to determine the exposure of anesthetist and endoscopist during pediatric bronchoscopy under halothane anesthesia in a worst-case working environment and to compare these measurements with the currently valid international threshold values. Ten children (ASA I-III) scheduled for diagnostic bronchoscopy were included in the study. After induction with thiopentone and relaxation with atracurium all children were intubated with a rigid bronchoscope and manually ventilated through a bypass of the bronchoscope. Anesthesia was maintained by means halothane (0.5-2.0 vol%) in 100% oxygen with a flow of 10 l/min. The investigation was done in an operating room without air conditioning and scavenging system. Trace concentrations were measured every 2 minutes in the breathing zones of the anesthetist and the endoscopist by means of a highly sensitive direct reading instrument. Lower detection limit was 0.02 ppm. The mean age (+/- SD) of the children was 29.9 +/- 15.9 months (range: 4 weeks-48 months). Ventilation and oxygenation were stable throughout the bronchoscopic procedure. Mean exposure (+/- SEM) to halothane was 57.7 +/- 18.9 ppm for the anesthetist and 96.3 +/- 22.9 ppm for the endoscopist. The difference was statistically significant (ANOVA, P < 0.05). All international threshold values (2-50 ppm) were exceeded by far. Peak concentrations higher than 200 ppm halothane could be detected several times. The main result of the present study is that under the given situation in the operating room with insufficient room ventilation and no scavenging system halothane anesthesia for rigid bronchoscopy in children results in an occupational exposure that is higher than all known health regulation guidelines. Therefore, in case of insufficient working conditions total intravenous anesthesia might be a better alternative also in very small infants.

Air Pollutants, Occupational↗
PubMed1996

[Serum fluoride concentrations and exocrine kidney function with sevoflurane and enflurane. An open, randomized, comparative phase III study of patients with healthy kidneys].

UNLABELLED: Sevoflurane is a "new" volatile inhaled anaesthetic. Owing to its lower blood-gas solubility coefficient, emergence from anaesthesia is faster with sevoflurane than with isoflurane, enflurane, or halothane. Sevoflurane undergoes metabolic biodegradation, releasing inorganic fluoride ions that could produce nephrotoxicity. In this study, we compared serum inorganic fluoride concentrations (IFCs) in patients receiving either sevoflurane or enflurane. Furthermore, indices of renal function were evaluated until the 3rd postoperative day. METHODS: Thirty patients with no history of renal or hepatic disease and with an anticipated duration of anaesthesia of at least 3 h were studied in an open, prospective, randomised clinical trial. Anaesthesia was induced with fentanyl, thiopentone, and vecuronium for facilitating endotracheal intubation. Anaesthesia was maintained with sevoflurane or enflurane, 60% nitrous oxide in oxygen, and additional doses of fentanyl. Blood samples for serum IFCs were obtained preoperatively and 2 and, if possible, 4 and 6 h after starting sevoflurane or enflurane, at the end of anaesthesia, and 1, 2, 4, 8, 12, 24, 48 and 72 h post-anaesthesia. Fluoride analysis was performed using an ion-selective electrode. Indices of renal function (serum sodium, osmolality, creatinine, urea, and uric acid, urine specific gravity, osmolality, and pH) were evaluated preoperatively, at the end of anaesthesia, and 24, 48, and 72 h post-anaesthesia. RESULTS: The duration of anaesthetic exposure was approximately 1.65 MAC-h for both inhaled anaesthetics. Peak serum IFCs were higher with sevoflurane (34.5 mumol/l) than with enflurane (19.4 mumol/l). Fluoride levels decreased more rapidly with sevoflurane: 24 h post-anaesthesia there was no difference between sevoflurane and enflurane (Fig. 1). The area under the curve (AUC) was greater with sevoflurane (688 mumol/l.h) than with enflurane (591 mumol/l.h). For both groups correlation coefficients were higher for MAC-h and AUC than for MAC-h and peak serum IFC (Figs. 2 and 3). Indices of renal function did not change in either group. DISCUSSION: In our study 1.69 MAC-h sevoflurane produced peak serum IFCs of 34.5 mumol/l. This is in accordance with the investigation of Frink et al. [4], who reported approximately 30 mumol/l after 1.4 MAC-h sevoflurane. Peak serum IFCs with sevoflurane were twice those with enflurane. Within the first 24 h post-anaesthesia, fluoride levels decreased more rapidly after sevoflurane. AUC may be more important than peak serum IFC in evaluating patients who are at risk for renal concentrating defects. In our study there was no evidence of renal dysfunction in either group.

Adult↗
PubMed1996

[Serum protein binding of fentanyl. The effect of postoperative acute phase reaction with elevated alpha 1-acid glycoprotein and methodologic problems in determination by equilibrium dialysis].

Numerous basic drugs are extensively bound to alpha 1-acid glycoprotein. Fentanyl, with a pKa value of 8.43, is also a basic drug. Protein binding studies have yielded contradictory results concerning binding of fentanyl to alpha 1-acid glycoprotein. In this study we investigated time courses of serum protein concentrations and serum protein binding of fentanyl during postoperative acute phase reaction, assuming that an increase of alpha 1-acid glycoprotein is accompanied by an increase of serum protein binding, if fentanyl is extensively bound to alpha 1-acid glycoprotein. Fentanyl protein binding measurements using equilibrium dialysis can be affected by volume shifts and pH changes. Therefore, volume shifts from buffer to serum and the influence of various phosphate buffers on increasing pH due to loss of CO2 were also evaluated. METHODS. Thirteen patients with no history of renal or hepatic disease undergoing an operation with a significant acute phase reaction were studied. Preoperatively and on the first 3 postoperative days serum concentrations of alpha 1-acid glycoprotein, albumin, total protein and apolipoprotein A and B were determined by rocket immunoeolectrophoresis, biuret method and laser nephelometry, respectively. Corresponding serum protein binding of fentanyl was measured by adding 40 ng of fentanyl to 1 ml serum followed by equilibrium dialysis at 37 degrees C for 4 h. A 0.167 M phosphate buffer (pH 7.27), which gave a final pH of 7.40, was used. Volume shifts from buffer to serum were measured. Fentanyl concentration in serum before dialysis (FS) was determined by gas chromatography, and fentanyl concentration in buffer after dialysis (FB) was determined by radioimmunoassay. Serum protein binding (SPB) was calculated by the formula: SPB = (FS - FB - FB*c)/(FS - FB) where c is a correction factor. Ten randomly selected patient sera were dialyzed against four phosphate buffers of different pH values and molarities, and the serum pH at the end of equilibrium dialysis was measured. RESULTS. Postoperatively, the serum concentration of alpha 1-acid glycoprotein rose to 151% of the control value. In contrast, serum protein binding of fentanyl did not change significantly, with a slight decrease to 96% of control value. There was a significant decrease in serum concentrations of albumin (3rd postoperative day), total protein (2nd postoperative day) and apolipoprotein B (1st-3rd postoperative day) to 85%, 90% and 75% of control values, respectively. Changes in apolipoprotein A concentration were not significant. Protein binding of fentanyl did not correlate with alpha 1-acid glycoprotein and apolipoprotein A, but there was a positive linear relationship between protein binding of fentanyl and albumin, total protein and apolipoprotein B. At the end of equilibrium dialysis the mean volumes of the serum and buffer compartments were 1114 +/- 72 and 834 +/- 68 microliters, respectively. The two phosphate buffers, with pH 7.30 (0.15 M) and pH 7.27 (0.167 M), gave final serum pH of 7.42 and 7.40, respectively. CONCLUSIONS. Present findings suggest that in contrast to other basic drugs, fentanyl binding to alpha 1-acid glycoprotein is of minor importance. In agreement with the findings of former studies, protein binding of fentanyl depended on albumin, total protein and apolipoprotein B concentrations. Due to unspecific binding of fentanyl by hydrophobic interactions, a major role of albumin, which amounts to about 60% of total protein, seems to be evident. Determining fentanyl protein binding by equilibrium dialysis, volume shifts must be taken into account if calculation is based on fentanyl concentrations in plasma (serum) and buffer after dialysis, and an appropriate buffer must be used.

Acute-Phase Reaction↗
PubMed1996

Evaluation of mixed venous oxygen saturation in chronic severe mitral regurgitation.

OBJECTIVE: The objective of this study was to evaluate whether chronic severe mitral regurgitation leads to an artifactual elevation of mixed venous oxygen saturation. DESIGN: Prospective study. SETTING: University hospital setting. PARTICIPANTS: Thirty patients with chronic severe mitral regurgitation undergoing surgery on the mitral valve and 25 patients without mitral regurgitation scheduled for elective coronary artery surgery. INTERVENTIONS: Blood samples were simultaneously withdrawn from the distal port and the paceport of a pulmonary artery catheter. MEASUREMENTS AND MAIN RESULTS: During steady-state-anesthesia, oxygen saturation and hemoglobin concentration were measured. There was no difference between mean oxygen saturation in blood from the pulmonary artery and the right ventricle in patients with mitral regurgitation, no matter whether large v waves were present, and in patients without mitral regurgitation. The distribution of individual differences between mixed venous and right ventricular oxygen saturation did not differ between groups. CONCLUSIONS: Because mixed venous oxygen saturation is not affected by chronic severe mitral regurgitation, it can be used in patients with mitral regurgitation just as in patients without mitral regurgitation.

Adult↗
PubMed1996

Effects of sevoflurane and isoflurane on systemic vascular resistance: use of cardiopulmonary bypass as a study model.

We have examined the dose-related effects of sevoflurane and isoflurane on systemic vascular resistance (SVR) during cardiopulmonary bypass (CPB) in patients undergoing elective coronary artery surgery. Fifty-two patients were allocated randomly to one of six groups to receive 1.0, 2.0 or 3.0 vol% (inspiratory) sevoflurane or 0.6, 1.2 or 1.8 vol% isoflurane, or to a control group. During hypothermic (32-33 degrees C) non-pulsatile CPB, systemic vascular resistance index (SVRI) was recorded before administration of volatile anaesthetics and every 5 min for 20 min. Sevoflurane and isoflurane concentrations were measured next to the gas inlet port and at the gas outlet port of the oxygenator. Wash-in of sevoflurane occurred more rapidly than that of isoflurane, reaching a relatively steady state for both agents from the 10th to the 20th min. There was no significant change in SVRI in patients receiving 1.0 and 2.0 vol% sevoflurane, and 0.6 and 1.2 vol% isoflurane, compared with baseline values. However, 3 vol% sevoflurane decreased SVRI at 10, 15 and 20 min, and 1.8 vol% isoflurane decreased SVRI significantly at 15 and 20 min, whereas SVRI increased at 15 and 20 min in the control group. Thus during CPB, sevoflurane had similar vasodilator effects on SVRI as isoflurane.

Adult↗
PubMed1995

[Rates of awakening, circulatory parameters and side-effects with sevoflurane and enflurane. An open, randomized, comparative phase III study].

OBJECTIVE: Sevoflurane is a "new" volatile inhaled anaesthetic currently undergoing phase III clinical trials in Europe and USA. Owing to the low blood solubility, rapid induction of anaesthesia and emergence from anaesthesia would be expected. In this study, we compared emergence times and haemodynamics in patients receiving either sevoflurane or enflurane. Furthermore, all adverse experiences were recorded, and the relationship to the drug administered was rated. METHODS: Thirty ASA physical status I and II patients were studied in an open, prospective and randomised clinical trial. Anaesthesia was induced with fentanyl, thiopentone and vecuronium for facilitating endotracheal intubation. Anaesthesia was maintained with sevoflurane or enflurane, 60% nitrous oxide in oxygen and additional doses of fentanyl (1-2 micrograms/kg/h). ECG, blood pressure (non-invasive), inspiratory and end-tidal concentrations of sevoflurane or enflurane were monitored continuously. At the end of surgery, administration of sevoflurane or enflurane and nitrous oxide stopped without tapering and emergence times were recorded. All adverse experiences which occurred until the third postoperative day were recorded and the relationship to the inhaled anaesthetic was rated as "none", "unlikely", "possible", "probable" or "highly probable". RESULTS: With the exception of the end-tidal concentration at the end of surgery and the mean inspiratory and end-tidal concentrations, which were higher for sevoflurane, the two patient groups were comparable. Pulmonary elimination was significantly faster and emergence time was significantly shorter (5 vs. 9 minutes) with sevoflurane. Emergence time did not correlate with the duration of anaesthetic exposure (MAC hours) for sevoflurane. There was no difference in the time courses of heart rate and mean arterial blood pressure between sevoflurane and enflurane. No adverse experiences with a "probable" or "highly probable" relationship to the inhaled anaesthetic were observed. CONCLUSION: Emergence time after inhalation anaesthesia depends on (alveolar) ventilation, blood-gas solubility coefficient and, at least for enflurane and isoflurane, on the dose applied (MAC hours). There is no positive correlation between emergence time and dose applied for sevoflurane. Due to the lower blood-gas solubility coefficient (0.6-0.7 for sevoflurane vs. 1.8 for enflurane) pulmonary elimination is faster and emergence time is shorter with sevoflurane. Supplementing inhalation anaesthesia with fentanyl, there is no difference in the time courses of heart rate and mean arterial blood pressure between sevoflurane and enflurane.

Adult↗
PubMed1995

[Nitrous oxide exposure of operating room personnel in intubation anesthesia].

INTRODUCTION: Epidemiological studies have shown that trace concentrations of inhalation anaesthetics polluting the air of operation theatre could have adverse effects on the personnel's health. Nitrous oxide (N2O) oxidizes vitamin B12 and thus decreases DNA production by inactivation of methionine synthase. Therefore, US and most European health authorities recommend threshold values to protect against potential health risks. These values range from 25 ppm to 100 ppm, expressed as time-weighted averages (TWA). There is a lack of data concerning measurements of trace concentrations under defined conditions. The aim of this study was to quantify levels of N2O in an operating theatre (OT) under modern working environment conditions. METHODS: Trace concentrations of N2O were determined in the OT at three personnel-related and three potential leakage related points and TWA's were calculated. Trace concentrations of N2O were measured directly by means of a highly sensitive photoacoustic infrared spectrometry analyser. The lower detection limit was 0.03 ppm. RESULTS: Values were below 100 ppm TWA at personnel-related locations. NIOSH 25 ppm threshold limit value was exceeded several times. Significant differences between location surgeon and anaesthetist and auxiliary nurse were detected (p < 0.05, Wilcoxon test). CONCLUSION: Exposure to N2O in a climatised OT is determined by several factors: 1. Efficacy of the air-conditioning with 20 changes per hour without recirculation, 2. OT size, 3. low leakage anaesthesia machine, and 4. avoidance of intermittent nitrous oxide supply during induction. Due to these factors, most measured values are below threshold values. In case of other concepts of room design such as ventilation and size, measured values may be higher.

Adult↗
PubMed1994

[Emergence times, hemodynamics and adverse effects of sevoflurane and isoflurane: an open, randomized, comparative phase iii study].

Sevoflurane is a "new" volatile inhaled anaesthetic that is currently undergoing phase III clinical trial in Europe and the United States. Owing to the low blood solubility, rapid induction of anaesthesia and emergence from anaesthesia would be expected. In this study, we compared emergence times and haemodynamics in patients receiving either sevoflurane or isoflurane. Furthermore, all adverse effects were recorded and the relationship to the drug administered was rated. METHODS. Fifty ASA physical status I and II patients were studied in an open, prospective, randomised clinical trial. Anaesthesia was induced with fentanyl, thiopentone, and vecuronium for facilitating endotracheal intubation and maintained with sevoflurane or isoflurane, 60% nitrous oxide (N2O) in oxygen (O2), and additional doses of fentanyl (1-2 micrograms/kg.h). The electrocardiogram, blood pressure (non-invasive), O2 saturation, temperature, and end-tidal concentrations of sevoflurane or isoflurane, N2O, and carbon dioxide were monitored continuously. At the end of surgery, administration of sevoflurane or isoflurane and N2O was discontinued without tapering and emergence times were recorded. All adverse events that occurred until the 3rd postoperative day were recorded and the relationship to the inhaled anaesthetic was rated as "none", "unlikely", "possible", "probable", or "highly probable". RESULTS. With the exception of gender, the two patient groups were comparable (Tables 1 and 2). Due to the higher MAC value, mean end-tidal concentrations were higher for sevoflurane (0.82% vs. 0.59% for isoflurane). The duration of anaesthetic exposure was 1.3 MAC h (calculation with FIO2 = 1.0 MAC value) and 3.1 MAC h (calculation with FIO2 = 0.4 in N2O MAC value), respectively, for both inhaled anaesthetics. Pulmonary elimination was faster (Fig. 1) and emergence time shorter (7 min vs. 11.5 min, Table 3) with sevoflurane. There was no difference in the time courses of heart rate and mean arterial blood pressure (Figs. 2 and 3). No adverse effects with a "probable" or "highly probable" relationship to the inhaled anaesthetic were observed. Table 4 shows the adverse events with a possible relationship to the drug administered. Further evaluations of nausea, vomiting, and dizziness are shown in Table 5. DISCUSSION. Emergence time after inhalation anaesthesia depends on pulmonary elimination and MACawake, that is, the end-tidal concentration that would allow opening of the eyes on verbal command. Pulmonary elimination depends on dose applied (MAC h), alveolar ventilation, and blood-gas solubility coefficient. Due to the lower blood-gas solubility coefficient (0.6-0.7 for sevoflurane vs. 1.3-1.4 for isoflurane) and in accordance with the investigations of Frink et al. [4] and Smith et al. [16], emergence time was significantly shorter with sevoflurane. Gender, the only difference between the two patient groups, does not influence pulmonary elimination and MACawake [8]. Supplementing inhalation anaesthesia with fentanyl, there was no difference in the time courses of heart rate and mean arterial blood pressure between sevoflurane and isoflurane. Adverse events with a possible relationship to the inhaled anaesthetic occurred in both groups.

Adult↗
PubMed1993

[Changes in suicide mortality in Germany].

OBJECTIVE: About one third of the total number of life lost in the period between 1 and 65 years in consequence of "external causes" (E-classification by WHO) in East and in West Germany account alone for "suicide" as a cause of death. Suicide alone produces, e.g. among the male population, a loss in years of life which corresponds to 53% (in East Germany) and to 40% (in West Germany), respectively, of the total number of years of life lost due to cancer of all organic localizations. METHODS: The analysis is based on the official mortality data from 1961 to 1989. The data are analysed by age and sex. SMR, average age of death and PYLL are calculated. RESULTS: A comparative survey of suicide mortality over the period from 1961 to 1989 has shown that there are differences in suicide frequencies between East and West Germany. If related to the whole period, the lowest suicide rates both in the East and in the West have been observed at the end of that period. The suicide mortality rate in the East, however, remained higher than in the West, by 79.9% (male population) and by 70.2% (female population), respectively. The long-term trend is characterised by a slight increase of the suicide gap between East and West among the male population, whereas the difference has diminished in respect of the female population. Sex-related differences are even more distinct than differences between East and West in suicide mortality. Thus, in 1989, the standardized suicide rates among the male population amounted to 2.7 times (West Germany) and 2.8 times (East Germany) of that of the female population, these differences having increased continually during the period from 1961 to 1989. CONCLUSIONS: The results cast justifiable doubts on whether the actual distribution of research capacities and of financial and personnel resources are adequate to cope with the problems raised by the phenomenon of "suicide".

Adolescent↗