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Biomedical subjects

J Rieder

Publications and source records attributed to J Rieder.

At least 19 recordsLinked to original sources
PubMed2005

Craniotomy during ECMO in a severely traumatized patient.

Extracorporeal membrane oxygenation (ECMO) can be a last resort treatment in acute respiratory distress syndrome after thoracic trauma. However, co-existent brain trauma is considered to be a contra-indication for ECMO. This is the first report on successful craniotomy under ECMO treatment in a multiply traumatized patient with severe thoracic and brain injuries. This successful treatment with beneficial neurological outcome suggests that ECMO therapy should not be withheld from severely injured patients with combined brain and thoracic trauma presenting with life-threatening hypoxemia. Moreover, even craniotomy may be performed during ECMO therapy without major bleeding and adverse effects on neurological function.

Accidental Falls↗
PubMed2005

Incidence of lower thoracic ligamentum flavum midline gaps.

BACKGROUND: Lower thoracic epidural anaesthesia and analgesia (EDA) has gained increasing importance in perioperative pain therapy. The loss-of-resistance technique used to identify the epidural space is thought to rely on the penetration of the ligamentum flavum. Investigations at the cervical and lumbar regions have demonstrated that the ligamentum flavum frequently exhibits incomplete fusion at different vertebral levels. Therefore, the aim of this study was to directly investigate the incidence of lower thoracic ligamentum flavum midline gaps in embalmed cadavers. METHODS: Vertebral column specimens were obtained from 47 human cadavers. Ligamentum flavum midline gaps were recorded between the vertebral levels T6 and L1. RESULTS: The incidence of midline gaps/number of viable specimens at the following levels was: T6-7: 2/45 (4.4%), T7-8: 1/47 (2.1%), T8-9: 2/45 (4.4%), T9-10: 7/39 (17.9%), T10-11: 12/34 (35.2%), T11-12: 10/35 (28.5%), T12/L1: 6/38 (15.8%). CONCLUSIONS: In the present study we have determined the frequency of lower thoracic ligamentum flavum midline gaps. Gaps are less frequent than at cervical levels, but more frequent than at lumbar levels. Peak incidence was found in the region between T10 and T12. Using a strict midline approach, one cannot therefore rely on the ligamentum flavum to impede entering the epidural space in all patients.

Adult↗
PubMed2005

Cisatracurium, but not mivacurium, induces apoptosis in human umbilical vein endothelial cells in vitro.

BACKGROUND AND OBJECTIVE: Cisatracurium is an intermediate acting, non-depolarizing neuromuscular blocking agent. Previous reports have indicated a growth-inhibitory effect of the isoforms cisatracurium and atracurium on two human cell lines in vitro. These effects were ascribed to oxidative stress elicited by acrylate esters formed during cisatracurium breakdown. Oxidative stress is a potent precipitator of apoptosis. Therefore, the aim of the present study was to investigate whether the growth-inhibitory effects of cisatracurium could be explained by initiation of apoptosis. METHODS: Human umbilical vein endothelial cells were incubated with cisatracurium at concentrations of 0.96, 3.2, 9.6, 32 and 96 micromol for 24 h. DNA fragmentation was measured using the Cell Death Detection ELISA Plus assay (Roche Diagnostics, Mannheim, Germany). RESULTS: There was a dose dependency of cisatracurium with respect to the rate of apoptosis in human umbilical vein endothelial cells. Programmed cell death could be demonstrated at concentrations encountered in human plasma after single-bolus injections of cisatracurium. Apoptosis was attenuated by the concomitant administration of glutathione. CONCLUSIONS: These findings strongly support the hypothesis that acrylate esters, breakdown products of cisatracurium, induce oxidative stress and, subsequently, apoptosis.

Antidotes↗
PubMed2004

Unintentional arterial puncture during cephalic vein cannulation: case report and anatomical study.

BACKGROUND: The cephalic antebrachial vein is often used for venous access. However, superficial radial arteries of the forearm are known and unintentional arterial puncture can result from attempts to cannulate the lateral veins of the arm. METHODS: Accidental puncture of a superficial radial artery during peripheral venous cannulation prompted us to study the anatomy of 26 specimens and to assess the relationship between the radial artery and the cephalic vein in the forearm. RESULTS: In two cases, we found accessory branches of the radial artery close to the cephalic forearm vein. Venous cannulation at the lateral wrist carries a small risk of arterial puncture if arterial anomalies are present. CONCLUSIONS: If venous cannulation is attempted at the radial side of the wrist, palpation for pulsation should reduce the danger of arterial puncture.

Aged↗
PubMed2004

Accuracy in estimating the correct intervertebral space level during lumbar, thoracic and cervical epidural anaesthesia.

BACKGROUND: Even in the absence of factors concealing anatomical landmarks, high failure rates in correctly determining a given lumbar interspace have been reported. METHODS: Therefore, it was the aim of the present study to compare the assessed and factual level (determined by computed tomography) of epidural puncture in attending a regional anaesthesia cadaver workshop. Eighty-two anaesthetists performed 117 punctures. RESULTS: Vertebral interspaces between T8-L4 were correctly identified more often than those between C3-T5 (P < 0.05). Identification of an arbitrarily chosen vertebral interspace was excellent in both the cervical/high thoracic and thoracic/lumbar regions. CONCLUSION: As previously conjectured only for the lumbar region, we could confirm the tendency of anaesthetists to perform neuraxial puncture more cranially than expected also for the thoracic and cervical regions. The large majority of punctures (93.7%) was performed within one interspace of the predicted level.

Anesthesia, Epidural↗
PubMed2004

Positive pressure versus pressure support ventilation at different levels of PEEP using the ProSeal laryngeal mask airway.

We compared positive pressure ventilation with pressure support ventilation at different levels of positive end expiratory pressure (PEEP) using the ProSeal laryngeal mask airway (PLMA). Forty-two anaesthetized adults (ASA 1-2, aged 19 to 63 years) underwent positive pressure ventilation and then pressure support ventilation each with PEEP set at 0, 5 and 10 cmH2O in random order. Pressure support ventilation was with the inspired tidal volume (VTInsp) set at 7 ml/kg and the respiratory rate adjusted to maintain the end-tidal CO2 (ETCO2) at 40 mmHg. Pressure support ventilation was with pressure support set at 5 cmH2O above PEEP and initiated when inspiration produced a 2 cmH2O reduction in airway pressure. Tidal volumes were similar during positive pressure and pressure support ventilation with PEEP, but were higher for the former without PEEP Respiratory rate and peak inspiratory flow rate were higher during pressure support than positive pressure ventilation (all P < 0.001). Peak airway pressure (Ppaw), mean airway pressure (Mpaw), peak expiratory flow rate, and expired airway resistance were lower during pressure support than positive pressure ventilation (all P < 0.001). With PEEP set at 10 cmH2O, ETCO2 was lower for pressure support than positive pressure ventilation. During positive pressure ventilation, there was an increase in Ppaw, Mpaw and dynamic compliance (Cdyn) with increasing levels of PEEP (all P < 0.01). During pressure support ventilation, there was an increase in inspired and expired tidal volume, Ppaw, peak inspiratory and expiratory flow rates and Cdyn, and a reduction in ETCO2, work of breathing, and expired airway resistance with increasing levels of PEEP (all P < 0.01). There were no differences in SpO2, non-invasive mean arterial pressure, heart rate or leak fraction. We conclude that pressure support ventilation provides equally effective gas exchange as positive pressure ventilation during PLMA anaesthesia with or without PEEP at the tested settings. During pressure support, PEEP increases ventilation and reduces work on breathing without increasing leak fraction.

Adult↗
PubMed2003

Sevoflurane in exhaled air of operating room personnel.

UNLABELLED: Evidence on potential health hazards arising from exposure to volatile anesthetics remains controversial. Exposure may, in principle, be supervised by monitoring of ambient air or, alternatively, in vivo. We used the Proton Transfer Reaction-Mass Spectrometry to screen the breath of 40 operating room staff members before operating room duty, 0, 1, 2, and 3 h after duty, and before commencing duty on the consecutive day, and control persons. Staff members exhibited significantly increased sevoflurane levels in exhaled air after duty, with a mean of 0.80 parts per billion as compared with baseline values of 0.26 parts per billion (P < 0.05). Analysis of variance with adjustment for within correlation (repeated measurements) showed a statistically significant time-effect (P < 0.001). We conclude that (a) Proton Transfer Reaction-Mass Spectrometry biomonitoring of exhaled sevoflurane can serve as a simple and rapid method to determine volatile anesthetic excretion after occupational exposure, and (b) significant concentrations of sevoflurane may be continuously present in persons exposed to sevoflurane on a daily basis. IMPLICATIONS: The present study depicts the profile of volatile anesthetics, isoflurane and sevoflurane, in exhaled air of ambulatory patients. Biomonitoring of expired anesthetic concentrations is a noninvasive and rapid method to determine volatile anesthetic excretion.

Adult↗
PubMed2002

Monitoring pollution by proton-transfer-reaction mass spectrometry during paediatric anaesthesia with positive pressure ventilation via the laryngeal mask airway or uncuffed tracheal tube.

Twenty children aged 2-66 months were randomly allocated for airway management with either the laryngeal mask airway or uncuffed tracheal tube using intermittent positive pressure ventilation with a tidal volume of 8 ml.kg-1 and a respiratory rate adjusted to maintain end-expiratory carbon dioxide concentration at 5.3 kPa. Induction was with fentanyl/propofol and maintenance was with sevoflurane 2.5% in oxygen/air. The airway device was removed when the patients were awake and the patients were transferred to the postanaesthesia care unit 10 min later. Air was sampled from a point 1.5 m above the floor at a location remote from the ventilation outlet and analysed using a proton-transfer-reaction mass spectrometer capable of continuous trace gas analysis at the parts per billion volume (ppbv) level. The concentration of sevoflurane was recorded every minute during three consecutive phases: for 5 min before the introduction of sevoflurane (background); after introduction of sevoflurane until removal of the airway device (intra-operative); and every minute after removal until the concentration returned to background levels. Median (interquartile range [range]) intra-operative sevoflurane concentrations were 200-400 times higher than background values for the laryngeal mask airway 1 (1-2 [0-3]) ppbv vs. 404 (278-523 [83-983]) ppbv, respectively, and the tracheal tube 2 (1-3 [0-5]) ppbv vs. 396 (204-589 [107-1735]) ppbv (both p < 0.0001), and returned to background values within 5 min of removal. There were no differences in sevoflurane concentration between devices intra-operatively or after removal. The performance of the proton-transfer-reaction mass spectrometer was identical at the start and end of the 30-day study. We conclude that peri-operative sevoflurane concentration in a modern operating theatre is similar for the laryngeal mask airway and the uncuffed tracheal tube in paediatric patients receiving intermittent positive pressure ventilation. Intra-operative sevoflurane concentrations are five times lower than occupational safety limit requirements, and 1000 times lower 5 min after removal of the airway device with the patient awake. The proton-transfer-reaction mass spectrometer has potential for monitoring air quality in the operating theatre.

Air Pollutants, Occupational↗
PubMed2002

Neopterin as a marker of immunostimulation: an investigation in anaesthetic workplaces.

Personnel working in operating theatres and recovery rooms are exposed to a variety of noxious substances. The results of studies of the effects of occupational exposure on immune parameters are conflicting. Neopterin is an acknowledged marker of immunostimulation. Urinary neopterin levels of 58 anaesthetists and anaesthetic nurses were measured over a 3-week period. Neopterin analyses were performed using high performance liquid chromatography. Neopterin levels were within the normal range for all subjects. Younger subjects (aged < or = 35 years) had significantly higher urinary neopterin concentrations than older subjects (aged > 35 years). The present study is the first to investigate the influence of anaesthetic exposure on neopterin levels. No evidence of immunostimulation was found.

Adult↗
PubMed2001

Analysis of volatile organic compounds: possible applications in metabolic disorders and cancer screening.

The human breath contains a variety of endogenous volatile organic compounds (VOCs). The origin and pathophysiological importance of these VOCs is poorly investigated. Little is known about the interaction of VOCs from ambient air, such as those produced by plants and exhaust fumes, with the human organism. Gas chromatographic determination of VOC concentrations is tedious. Proton-transfer-mass spectroscopy (PTR-MS), a new technology for the online detection of VOC patterns, is a valuable alternative. We present two interesting molecular species, isoprene and ortho (o)-toluidine, as examples of endogenously produced VOCs. In a case study, breath isoprene reductions during lipid-lowering therapy (36%) were shown to correlate with cholesterol (32%) and LDL concentrations (35%) in blood (p < 0.001) over a period of 15 days. Therefore, isoprene concentrations in human breath (measured by PTR-MS) might serve as an additional parameter to complement invasive tests for controlling lipid-lowering therapy. Furthermore, it may be a useful parameter for lipid disorder screening. Mass-108, which presumably represents o-toluidine in our breath samples, was found in significantly higher concentrations in the breath of patients with different tumors (1.5 +/- 0.8 ppbv) than in age-matched controls (0.24 +/- 0.1 ppbv, p < 0.001). Inflammatory reactions do not seem to alter the pattern of mass-108. Therefore, it appears to be a currently underestimated carcinoma marker that deserves further investigation.

Adult↗
PubMed2001

Nitric oxide-dependent apoptosis in ovarian carcinoma cell lines.

OBJECTIVE: In a recent study, we found different profiles of inducible nitric oxide synthase (iNOS) gene expression in the ovarian carcinoma cell lines OVCAR-3, HOC-7, and 2774 following stimulation by proinflammatory cytokines. The present study was performed to determine whether nitric oxide (NO) synthesis correlates with programmed cell death in these cells. METHODS: NO-Dependent apoptosis was detected by DNA fragmentation analysis and fluorescence-activated cell sorter analysis. RESULTS: NO formation in response to interferon gamma (IFN-gamma), interleukin-1beta (IL-1beta), and tumor necrosis factor alpha (TNF-alpha) was correlated with programmed cell death in the investigated cells. DNA fragmentation was most prominent in OVCAR-3 (34.17 +/- 1.81%), less pronounced in HOC-7 (12.86 +/- 0.45%), and undetectable in 2774 (4.54 +/- 0.40%) cells. The rate of apoptosis correlated with the amount of NO formation in cytokine-treated cells. Moreover, coincubation of OVCAR-3 and HOC-7 with the specific iNOS inhibitor aminoguanidine suppressed apoptosis induced by IFN-gamma, IL-1beta, and TNF-alpha. CONCLUSION: Our data indicate that in OVCAR-3 and HOC-7 cells, NO synthesis induced by IFN-gamma, IL-1beta, and TNF-alpha is correlated with the degree of apoptotic cell death. In clinical situations, this might in part explain the benefit of cytokine application in ovarian carcinoma patients (e.g., documented for IFN-gamma).

Apoptosis↗
PubMed2001

Analysing ventricular fibrillation ECG-signals and predicting defibrillation success during cardiopulmonary resuscitation employing N(alpha)-histograms.

Mean fibrillation frequency may predict defibrillation success during cardiopulmonary resuscitation (CPR). N(alpha)-histogram analysis should be investigated as an alternative. After 4 min of cardiac arrest, and 3 versus 8 min of CPR, 25 pigs received either vasopressin or epinephrine (0.4, 0.4, and 0.8 U/kg vasopressin versus 45, 45, and 200 microg/kg epinephrine) every 5 min with defibrillation at 22 min. Before defibrillation, the N(alpha)-parameter histogramstart/histogramwidth and the mean fibrillation frequency in resuscitated versus non-resuscitated pigs were 2.9+/-0.4 versus 1.7+/-0.5 (P=0.0000005); and 9.5+/-1.7 versus 6.9+/-0.7 (P=0.0003). During the last minute prior to defibrillation, histogramstart/histogramwidth of > or =2.3 versus mean fibrillation frequency > or =8 Hz predicted successful defibrillation with subsequent return of a spontaneous circulation for more than 60 min with sensitivity, specificity, positive predictive value and negative predictive value of 94 versus 82%, 96 versus 89%, 98 versus 93% and 90 versus 74%, respectively. We conclude, that N(alpha)-analysis was superior to mean fibrillation frequency analysis during CPR in predicting defibrillation success, and distinction between vasopressin versus epinephrine effects.

Algorithms↗
PubMed2001

Monitoring of immune activation using biochemical changes in a porcine model of cardiac arrest.

In animal models, immune activation is often difficult to assess because of the limited availability of specific assays to detect cytokine activities. In human monocytes/macrophages, interferon-gamma induces increased production of neopterin and an enhanced activity of indoleamine 2,3-dioxygenase, which degrades tryptophan via the kynurenine pathway. Therefore, monitoring of neopterin concentrations and of tryptophan degradation can serve to detect the extent of T helper cell 1-type immune activation during cellular immune response in humans. In a porcine model of cardiac arrest, we examined the potential use of neopterin measurements and determination of the tryptophan degradation rate as a means of estimating the extent of immune activation. Urinary neopterin concentrations were measured with high-performance liquid chromatography (HPLC) and radioimmunoassay (RIA) (BRAHMS Diagnostica, Berlin, Germany). Serum and plasma tryptophan and kynurenine concentrations were also determined using HPLC. Serum and urine neopterin concentrations were not detectable with HPLC in these specimens, whereas RIA gave weakly (presumably false) positive results. The mean serum tryptophan concentration was 39.0 +/- 6.2 micromol/l, and the mean kynurenine concentration was 0.85 +/- 0.33 micromol/l. The average kynurenine-per-tryptophan quotient in serum was 21.7 +/- 8.4 nmol/micromol, and that in plasma was 20.7 +/- 9.5 nmol/micromol (n = 7), which corresponds well to normal values in humans. This study provides preliminary data to support the monitoring of tryptophan degradation but not neopterin concentrations as a potential means of detecting immune activation in a porcine model. The kynurenine-per-tryptophan quotient may serve as a short-term measurement of immune activation and hence permit an estimate of the extent of immune activation.

Animals↗
PubMed2001

Online monitoring of air quality at the postanesthetic care unit by proton-transfer-reaction mass spectrometry.

The subthreshold exposure to trace anesthetic gases is not associated with considerable risk of adverse health effects. Online control of ambient air exchange at the postoperative workplace may help in supervising air quality and lead to cost reduction. A proton-transfer-reaction mass spectrometer system was used for online monitoring of volatile organic compounds, especially anesthetic gases. The mean exposure to sevoflurane and isoflurane at the urological postanesthesia care unit (PACU) was 15.9 and 9.5 parts per billion, respectively. Sevoflurane and isoflurane concentrations at the urological PACU showed a patient turnover-dependent burden during our investigation period. Because modern PACUs have a high ventilation capacity, the 24-h occupational burden by anesthetic gases at the PACU is relatively low. Monitoring and controlling of ambient air by automatic built-in alarm systems would be useful for quality control of the postoperative workplace. Moreover, energy costs of ventilation systems could be reduced by coupling ventilation capacity to the effective exposure.

Air Pollutants, Occupational↗