Conventional versus video-assisted laryngoscopy for perioperative endotracheal intubation (COVALENT) - a randomized, controlled multicenter trial.

BACKGROUND: Data on the routine use of video-assisted laryngoscopy in peri-operative intubations are rather inconsistent and ambiguous, in part due to small populations and non-uniform outcome measures in past trials. Failed or prolonged intubation procedures are a reason for relevant morbidity and mortality. This study aims to determine whether video-assisted laryngoscopy (with both Macintosh-shaped and hyperangulated blades) is at least equal to the standard method of direct laryngoscopy with respect to the first-pass success rate. Furthermore, validated tools from the field of human factors will be applied to examine within-team communication and task load during this critical medical procedure. METHODS: In this randomized, controlled, three-armed parallel group design, multi-centre trial, a total of more than 2500 adult patients scheduled for perioperative endotracheal intubation will be randomized. In equally large arms, video-assisted laryngoscopy with a Macintosh-shaped or a hyperangulated blade will be compared to the standard of care (direct laryngoscopy with Macintosh blade). In a pre-defined hierarchical analysis, we will test the primary outcome for non-inferiority first. If this goal should be met, the design and projected statistical power also allow for subsequent testing for superiority of one of the interventions. Various secondary outcomes will account for patient safety considerations as well as human factors interactions within the provider team and will allow for further exploratory data analysis and hypothesis generation. DISCUSSION: This randomized controlled trial will provide a solid base of data in a field where reliable evidence is of major clinical importance. With thousands of endotracheal intubations performed every day in operating rooms around the world, every bit of performance improvement translates into increased patient safety and comfort and may eventually prevent significant burden of disease. Therefore, we feel confident that a large trial has the potential to considerably benefit patients and anaesthetists alike. TRIAL REGISTRATION: ClincalTrials.gov NCT05228288. PROTOCOL VERSION: 1.1, November 15, 2021.

Guiding Attention via a Cognitive Aid During a Simulated In-Hospital Cardiac Arrest Scenario: A Salience Effort Expectancy Value Model Analysis.

OBJECTIVE: To investigate the effect of a cognitive aid on the visual attention distribution of the operator using the Salience Effort Expectancy Value (SEEV) model. BACKGROUND: Cognitive aids aim to support an operator during the execution of a task. The effect of cognitive aids on performance is frequently evaluated but whether a cognitive aid improved, for example, attention distribution has not been considered. METHOD: We built the Expectancy Value (EV) model version which can be considered to indicate optimal attention distribution for a given event. We analyzed the eye tracking data of emergency physicians while using a cognitive aid application versus no application during a simulated in-hospital cardiac arrest scenario. RESULTS: The EV model could fit the attention distribution in such a simulated emergency situation. Partially supporting our hypothesis, the cognitive aid application group showed a significantly better EV model fit than the no application group in the first phases of the event, but a worse fit in the last phase. CONCLUSION: We demonstrated that a cognitive aid affected attention distribution and that the SEEV model provides the means of capturing these effects. We suggest that the aid supported and improved visual attention distribution in the stressful first phases of a cardiopulmonary resuscitation but may have focused attention on objects that are relevant for lower priority goals in the last phase. APPLICATION: The SEEV model can provide insights into expected and unexpected effects of cognitive aids on visual attention distribution and may help to design better artifacts.

The Validity of the SEEV Model as a Process Measure of Situation Awareness: The Example of a Simulated Endotracheal Intubation.

OBJECTIVE: In the context of anesthesiology, we investigated whether the salience effort expectancy value (SEEV) model fit is associated with situation awareness and perception scores. BACKGROUND: The distribution of visual attention is important for situation awareness-that is, understanding what is going on-in safety-critical domains. Although the SEEV model has been suggested as a process situation awareness measure, the validity of the model as a predictor of situation awareness has not been tested. METHOD: In a medical simulation, 31 senior and 30 junior anesthesiologists wore a mobile eye tracker and induced general anesthesia into a simulated patient. When inserting a breathing tube into the mannequin's trachea (endotracheal intubation), the scenario included several clinically relevant events for situation awareness and general events in the environment. Both were assessed using direct awareness measures. RESULTS: The overall SEEV model fit was good with no difference between junior and senior anesthesiologists. Overall, the situation awareness scores were low. As expected, the SEEV model fits showed significant positive correlations with situation awareness level 1 scores. CONCLUSION: The SEEV model seems to be suitable as a process situation awareness measure to predict and investigate the perception of changes in the environment (situation awareness level 1). The situation awareness scores indicated that anesthesiologists seem not to perceive the environment well during endotracheal intubation. APPLICATION: The SEEV model fit can be used to capture and assess situation awareness level 1. During endotracheal intubation, anesthesiologists should be supported by technology or staff to notice changes in the environment.

Why and How to Approach User Experience in Safety-Critical Domains: The Example of Health Care.

OBJECTIVE: To highlight the importance of the personal experience of users who interact with technology in safety-critical domains and summarize three interaction concepts and the associated theories that provide the means for addressing user experience. BACKGROUND: In health care, the dominant concepts of interaction are based on theories arising from classic cognitive psychology. These concepts focus mainly on safety and efficiency, with too little consideration being given to user experience. METHOD: Users in complex socio-technical and safety-critical domains such as health care interact with many technological devices. Enhancing the user experience could improve the design of technology, enhance the well-being of staff, and contribute to modern safety management. We summarize concepts of "interaction" based on modern theories of human-computer interaction, which include the personal experience of users as an important construct. RESULTS AND CONCLUSION: Activity theory, embodiment, and interaction as experience provide a theoretical foundation for considering user experience in safety-critical domains. Using an example from anesthesiology, we demonstrate how each theory provides a unique but complementary view on experience. Finally, the methodological possibilities for considering personal experience in design and evaluations vary among the theories. APPLICATION: Considering user experience in health care and potentially other safety-critical domains can provide an additional means of optimizing interaction with technology, contributing to the well-being of staff, and improving safety.

[Anesthesiology Seminar in Times of COVID-19: a Hybrid Model evolving from Digital and Virtual Lessons]. / Anästhesiologische Lehre in Zeiten von Corona ­ von der Präsenzlehre zum Hybridmodell.

On March 14, 2020, the first Bavaria-wide exit restriction was imposed and university teaching in its familiar form was drastically restricted. For intensive care physicians and anesthetists, there was a special area of tension in many places due to the extraordinary demand for the treatment of critically ill patients and the restructuring and maintenance of teaching. We report on the realignment of the anesthesia seminar in an online flipped classroom and the development towards a hybrid model. As such, an adequate transfer of knowledge could take place under difficult conditions and at the same time the teaching concept could be further developed.

Trace-level determination of phosphonates in liquid and solid phase of wastewater and environmental samples by IC-ESI-MS/MS.

Phosphonates are increasingly used as water-softening agents in detergents, care products, and industrial processes. Despite poor biodegradability, high removal rates during wastewater treatment (WWT) have been observed, owing to strong adsorption affinity to activated sludge and mineral surfaces. Due to phosphonates representing challenging analytes, no method for the compound-specific quantification of phosphonates from solid samples has hitherto been published. In order to improve the data foundation on the environmental fate of phosphonates, an analytical method based on anion exchange chromatography and detection by electrospray ionization coupled to tandem mass spectrometry (IC-ESI-MS/MS) was developed, allowing the trace quantification of phosphonates from surface water (LOQs between 0.04 and 0.16 µg/L), wastewater (LOQs between 0.6 and 2.3 µg/L), sediment and suspended matter of rivers (LOQ < 0.1 mg/kg), and suspended matter of wastewater (LOQ < 1 mg/kg). Specificity and selectivity were enhanced by the implementation of isotope-labeled internal phosphonate standards derived through synthesis. This study describes the development of a comprehensive tool set for the determination of aminotris(methylenephosphonic acid) (ATMP), diethylenetriaminepenta(methylenephosphonic acid) (DTPMP), ethylenediaminetetra(methylenephosphonic acid) (EDTMP), 1-hydroxyethanediphosphonic acid (HEDP), and 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC) during WWT and in the aqueous environment. In the investigated matrices, HEDP and PBTC were generally present in highest and EDTMP in lowest abundance. The phosphonate contents detected in river water were in the sub to low µg/L range, depending on the wastewater burden, whereas contents in the low to medium µg/L range were found in untreated wastewater. The loads of the solid phases exceeded the contents of the corresponding liquid phases by roughly three orders of magnitude. Current data imply that phosphonates undergo significant partitioning to the solid phase during WWT and in natural water bodies. Graphical abstract.

An exploratory clinical evaluation of a head-worn display based multiple-patient monitoring application: impact on supervising anesthesiologists' situation awareness.

PURPOSE: Supervising anesthesiologists overseeing several operating rooms must be aware of the status of multiple patients, so they can consult with the anesthetist in single operating rooms or respond quickly to critical events. However, maintaining good situation awareness can be challenging when away from patient bedsides or a central monitoring station. In this proof-of-concept study, we evaluated the potential of a head-worn display that showed multiple patients' vital signs and alarms to improve supervising anesthesiologists' situation awareness. METHODS: Eight supervising anesthesiologists each monitored the vital signs of patients in six operating rooms for 3 h with the head-worn display, and for another 3 h without the head-worn display. In interviews with each anesthesiologist, we assessed in which situations the head-worn display was used and whether the continuous availability of the vital signs improved situation awareness. We also measured situation awareness quantitatively from six of the eight anesthesiologists, by instructing them to press a button whenever they noticed a patient alarm. RESULTS: The median number of patient alarms occurring was similar when the anesthesiologists monitored with the head-worn display (42.0) and without the head-worn display (40.5). However, the anesthesiologists noticed significantly more patient alarms with the head-worn display (66.7%) than without (7.1%), P = 0.028, and they reported improved situation awareness with the head-worn display. The head-worn display helped the anesthesiologists to perceive and comprehend patients' current status and to anticipate future developments. A negative effect of the head-worn display was its tendency to distract during demanding procedures. CONCLUSIONS: Head-worn displays can improve supervising anesthesiologists' situation awareness in multiple-patient monitoring situations. The anesthesiologists who participated in the study expressed enthusiasm about monitoring patients with a head-worn display and wished to use and evaluate it further.

Improved recall of handover information in a simulated emergency - A randomised controlled trial.

Background: Handovers during medical emergencies are challenging due to time-critical, dynamic and oftentimes unorderly and distracting situations. We evaluated the effect of distraction-reduced clinical surroundings during handover on (1) the recall of handover information, (2) the recall of information from the surroundings and (3) self-reported workload in a simulated in-hospital cardiac arrest scenario. Methods: In a parallel group design, emergency team leaders were randomly assigned to receive a structured handover of a cardio-pulmonary resuscitation (CPR) either inside the room ("inside group") right next to the ongoing CPR or in front of the room ("outside group") with no audio-visual distractions from the ongoing CPR. Based on the concept of situation awareness, the primary outcome was a handover score for the content of the handover (0-19 points) derived from the pieces of information given during handover. Furthermore, we assessed team leaders' perception of their surroundings during the scenario (0-5 points) and they rated their subjective workload using the NASA Task Load Index. Results: The outside group (n = 30) showed significant better recall of handover information than the inside group (n = 30; mean difference = 1.86, 95% CI = 0.67 to 3.06, p = 0.003). The perception of the surroundings (n = 60; mean difference = -0.27, 95% CI = -0.85 to 0.32, p = 0.365) and the NASA Task Load Index (n = 58; mean difference = 1.1; p = 0.112) did not differ between the groups. Conclusions: Concerning in-hospital emergencies, a structured handover in a distraction reduced environment can improve information uptake of the team leader.

[Helsinki Declaration on Patient Safety in Anaesthesiology--Part 8: SOP for checking equipment and drugs]. / Deklaration von Helsinki zur Patientensicherheit in der Anästhesiologie--Teil 8: SOP zur Überprüfung von Geräten und Medikamenten.

In 2010 the Helsinki Declaration on Patient Safety in Anaesthesiology was launched. In this joined statement under the auspice of the European Society of Anaesthesiology the need for protocols for different aspects of perioperative procedures that could affect patient safety was stated. All participating institutions should have--among others--protocols for checking equipment and drugs required for the delivery of safe anaesthesia. The background for this being the fact that the lack of carefully checking equipment and drugs--or not adhering to existing checklists--is a latent threat to patient safety and thus may increase morbidity and mortality.In this part of a series the authors present protocols existing in their clinic for checking anaesthesia equipment and drugs.

[Training for real: simulation, team-training and communication to improve trauma management]. / Schockraummanagement--Simulation, Teamtraining und Kommunikation für eine bessere Traumaversorgung.

The focus on the role of non-technical skills such as communication, dynamic decision making, situational awareness and teamwork in emergency medicine has gained importance over the past few years. Especially during time-critical and complex treatment of severely injured patients in a multidisciplinary and interprofessional trauma-team these factors play an important role for patient-safety and process optimization and are a key factor influencing the perceived quality of a given scenario by the team members. Thus, apart from medical expertise and technical excellence of single actors within a trauma team, non-technical skills need to be incorporated in trainings for trauma management. For the improvement of non-technical skills, particularly team communication and teamwork, a simulator-based training represents a valuable tool. The technical performance of portable manikin-based simulators has improved tremendously during the last decade, which facilitates realistic and true-to-life multidisciplinary team-training in trauma management.

Characterization of phosphonate-based antiscalants used in drinking water treatment plants by anion-exchange chromatography coupled to electrospray ionization time-of-flight mass spectrometry and inductively coupled plasma mass spectrometry.

In drinking water production, phosphonates are frequently applied as antiscalants in order to prevent the precipitation of salts on reverse osmosis membranes. Whereas the nominal constituents are defined, phosphonate-based antiscalants were found to contain significant amounts of undeclared phosphorous contaminants, particularly noticeable technical diethylenetriamine penta(methylene phosphonic acid) (DTPMP). Following a literature review on impurities of phosphonic acids, separation by anion exchange chromatography coupled with ICP-MS- and ESI-TOF-detection allowed the comprehensive characterization of technical phosphonates. After the identification of synthesis by-products, intermediates and degradation products, the quantification of the phosphorus compounds was accomplished by complementary phosphorus-sensitive ICP-MS detection. The contents of the nominal constituents as well as the organophosphorous impurities of 24 technical antiscalants were determined and compared with the manufacturer's declaration. Of all compounds detected within the technical formulations, 86% were confirmed with reference compounds. Phosphorous impurities were found to contribute to the total phosphorus content with close to 20% (in ATMP- and PBTC-based products) and 38%-65% (in DTPMP-based products). Correspondingly, the nominal compounds were found to contribute with 78%-80% (based on 6 ATMP products) and with 81.5%-83% (based on 2 PBTC products), whereas in 10 out of 12 DTPMP products the nominal compound was found to contribute with 34%-44% to the total phosphorus. Only in two products, elevated DTPMP proportions of 55% and 62% with regard to total phosphorus were determined. The screening for aminomethylphosphonic acid (AMPA) revealed contents between 1.9 mg/L and 157 mg/L. This study represents the first in-depth characterization of phosphonate-based antiscalant products and stock solutions used for drinking water production.

Approach for analytical characterization and toxicological assessment of ozonation products in drinking water on the example of acesulfame.

The monitoring and control of drinking water quality is generally important as it significantly contributes to the health of the population. In this context, particular attention has to be paid to the use of treatment techniques during drinking water treatment. It is known that the formation of reaction products (transformation products) has to be taken into account when oxidizing agents such as ozone are used. Different transformation products are classified as critical to health and require analytical examination. The risk assessment for previously unknown transformation products can be difficult as far as not all transformation products are present as single substances or the individual substances are not present in a sufficient high concentration or cannot be isolated from the original solution. The aim of this work is to show exemplarily the identification and quantification of ozonation products (OPs) after ozonation and their toxicological characterization, using the artificial sweetener acesulfame. It was shown that OPs can be fully characterized using ion chromatography in combination with different detection systems. A major OP could be recovered as a pure substance by crystallization and direct genotoxicological testing was possible without previous enrichment processes. Acesulfame samples of different concentrations in ultrapure and in drinking water after ozonation were tested in several genotoxicity tests. These tests revealed genotoxic effects of acesulfame after ozonation in ultrapure water in several genotoxicological test systems (micronucleus test, umu test, Ames-fluctuation-test and comet assay). In contrast, the crystallized ozonation product OP168 did not show any positive effects. Therefore, it seems likely that the observed effect was caused by the second major product OP170. However, a sufficiently large amount of analytically pure substance OP170 could not be obtained. It was also shown that the rate of the OP170 formation in drinking water is significantly lower than in ultrapure water and that ozonation in drinking water did not induce genotoxic effects.

Closing the gap - inclusion of ultrashort-chain perfluoroalkyl carboxylic acids in the total oxidizable precursor (TOP) assay protocol.

An improved protocol of the total oxidizable precursor (TOP) assay was developed for precursors to C2-C14 perfluoroalkyl carboxylic acids (PFCAs) and C4-C8 and C10 perfluoroalkyl sulfonic acids (PFSAs). The proposed protocol was tested and validated for contaminated soil samples. The perfluoroalkyl acids (PFAAs) present in the soil extract solutions after oxidation with persulfate were separated from the inorganic salts by vacuum-assisted drying of the digestion solution followed by solid-liquid extraction of the PFAAs with acetonitrile from the dry residue. Ion chromatography (for C2-C4 PFCAs) and reversed phase liquid chromatography (for all other PFASs), both coupled to tandem mass spectrometry, were used for quantification. High procedural recoveries of PFAAs between 68% and 123% with RSDs between 0.2% and 25% (n = 3) were achieved. The method was validated using selected polyfluoroalkyl phosphoric acid esters (PAPs) and bis-[2-(N-ethyl perfluorooctane-1-sulfonamido)ethyl] phosphoric acid ester (diSAmPAP) as model precursors in pure solutions and in the presence of soil matrix. The oxidation led to characteristic and reproducible PFCA patterns (in the case of PAPs) or PFOA (in the case of diSAmPAP) with total reaction yields between 92 ± 4% and 123 ± 13% (n = 3). The impact of the soil matrix on transformation yields was negligible. In a soil core from a PFAS-polluted agricultural site, precursors were concentrated in the upper 40 cm with long-chain precursors being prevalent. After oxidative digestion, the total molar PFAA-concentrations increased by factors of 1.6 to 5.0. More than 40 cm below ground precursors of TFAA, PFPrA and PFBA accounted for ∼50% of the reaction products, underlining the importance of their inclusion in mass balances based on the TOP assay.

Separation and characterization of aluminium malate species by ion chromatography.

Aluminium malate complexes have a high relevance in biological systems. The anionic species present in an aqueous aluminium malate mixture can be investigated by ion chromatography coupled online with inductively coupled plasma atomic emission spectroscopy. As malic acid is a chiral ligand, the experiments were carried out using the racemic and the enantiopure forms. In both systems four anionic complexes are observable in the model solutions. One of two crystallized and well-characterized anions, [Al(4)Malate(6)](6-) and [Al(4)Malate(4)](2-), serves as a reference anion for the assignment of one of the species occurring in the model solutions. The main species in the enantiopure aluminium malate model with biological relevance over a wide pH range is the [Al(4)Malate(4)](2-) anion. The [Al(4)Malate(6)](6-) anion is not present in the racemic model solution. This anion suffers complete species disintegration after dissolution. The kinetics of the decay is first order and the activation energy of the decomposition is 74 kJ/mol. A retention model for ion chromatography was used for the determination of the effective charges of the species. The effective charge obtained by the retention model was calibrated in relation to nominal charges of the anions by using several well-defined and differently charged anions and anionic aluminium species.

Small, mobile, persistent: Trifluoroacetate in the water cycle - Overlooked sources, pathways, and consequences for drinking water supply.

Elevated concentrations of trifluoroacetate (TFA) of more than 100 µg/L in a major German river led to the occurrence of more than 20 µg/L TFA in bank filtration based tap waters. Several spatially resolved monitoring programs were conducted and discharges from an industrial company were identified as the point source of TFA contamination. Treatment options for TFA removal were investigated at full-scale waterworks and in laboratory batch tests. Commonly applied techniques like ozonation or granulated activated carbon filtration are inappropriate for TFA removal, whereas TFA was partly removed by ion exchange and completely retained by reverse osmosis. Further investigations identified wastewater treatment plants (WWTPs) as additional TFA dischargers into the aquatic environment. TFA was neither removed by biological wastewater treatment, nor by a retention soil filter used for the treatment of combined sewer overflows. WWTP influents can even bear a TFA formation potential, when appropriate CF3-containing precursors are present. Biological degradation and ozonation batch experiments with chemicals of different classes (flurtamone, fluopyram, tembotrione, flufenacet, fluoxetine, sitagliptine and 4:2 fluorotelomer sulfonate) proved that there are yet overlooked sources and pathways of TFA, which need to be addressed in the future.

Characterization of stable aluminium-citrate species as reference substances for aluminium speciation by ion chromatography.

Well-defined anionic aluminium-citrate species are accessible from crystalline aluminium complexes. The solution chemistry of those species can be investigated using ion chromatography as a powerful tool for aluminium speciation in aqueous samples. The separation of three anionic aluminium-citrate complexes by anion exchange chromatography is possible within 5 min using isocratic conditions. The element specific detection was done by online coupled ICP-AES. The remaining charge of the complexes after dissolution can be determined by ion chromatography using a retention model. Time-dependent monitoring of the species distribution gave information about the species stabilities and the decomposition pathways. With citric acid as an aluminium chelator partially very stable anionic species are observed. These complexes are important components in biological systems. An example for the practical use of the separation method and the well-defined standards is given for plant sap, which showed two species with similar behavior compared to the investigated stable aluminium-citrate complexes.

Emerging nitrogenous disinfection byproducts: Transformation of the antidiabetic drug metformin during chlorine disinfection of water.

As an environmental contaminant of anthropogenic origin metformin is present in the high ng/L- up to the low µg/L-range in most surface waters. Residues of metformin may lead to the formation of disinfection by-products during chlorine disinfection, when these waters are used for drinking water production. Investigations on the underlying chemical processes occurring during treatment of metformin with sodium hypochlorite in aqueous medium led to the discovery of two hitherto unknown transformation products. Both substances were isolated and characterized by HPLC-DAD, GC-MS, HPLC-ESI-TOF, (1)H-NMR and single-crystal X-ray structure determination. The immediate major chlorination product is a cyclic dehydro-1,2,4-triazole-derivate of intense yellow color (Y; C4H6ClN5). It is a solid chlorimine of limited stability. Rapid formation was observed between 10 °C and 30 °C, as well as between pH 3 and pH 11, in both ultrapure and tap water, even at trace quantities of reactants (ng/L-range for metformin, mg/L-range for free chlorine). While Y is degraded within a few hours to days in the presence of light, elevated temperature, organic solvents and matrix constituents within tap water, a secondary degradation product was discovered, which is stable and colorless (C; C4H6ClN3). This chloroorganic nitrile has a low photolysis rate in ambient day light, while being resistant to heat and not readily degraded in the presence of organic solvents or in the tap water matrix. In addition, the formation of ammonia, dimethylamine and N,N-dimethylguanidine was verified by cation exchange chromatography.

Monitoring of in-hospital cardiac arrest events with the focus on Automated External Defibrillators--a retrospective observational study.

BACKGROUND: Patients with cardiac arrest have lower survival rates, when resuscitation performance is low. In In-hospital settings the first responders on scene are usually nursing staff without rhythm analysing skills. In such cases Automated External Defibrillators (AED) might help guiding resuscitation performance. At the Wuerzburg University Hospital (Germany) an AED-program was initiated in 2007. Aim of the presented study was to monitor the impact of Automated External Defibrillators on the management of in-hospital cardiac arrest events. METHODS: The data acquisition was part of a continuous quality improvement process of the Wuerzburg University Hospital. For analysing the CPR performance, the chest compression rate (CCR), compression depth (CCD), the no flow fraction (NFF), time interval from AED-activation to the first compression (TtC), the time interval from AED-activation to the first shock (TtS) and the post schock pause (TtCS) were determined by AED captured data. A questionnaire was completed by the first responders. RESULTS: From 2010 to 2012 there were 359 emergency calls. From these 53 were cardiac arrests with an AED-application. Complete data were available in 46 cases. The TtC was 34 (32-52) seconds (median and IQR).The TtS was 30 (28-32) seconds (median and IQR). The TtCS was 4 (3-6) seconds (median and IQR). The CCD was 5.5 ± 1 cm while the CCR was 107 ± 11/min. The NFF was calculated as 41 %. ROSC was achieved in 21 patients (45 %), 8 patients (17 %) died on scene and 17 patients (37 %) were transferred under ongoing CPR to an Intensive Care Unit (ICU). CONCLUSION: The TtS and TtC indicate that there is an AED-user dependent time loss. These time intervals can be markedly reduced, when the user is trained to interrupt the AED's "chain of advices" by placing the electrode-paddles immediately on the patient's thorax. At this time the AED switches directly to the analysing mode. Intensive training and adaption of the training contents is needed to optimize the handling of the AED in order to maximize its advantages and to minimize its disadvantages.

Transformation of the artificial sweetener acesulfame by UV light.

The transformation of the artificial sweetener acesulfame by direct photolysis was investigated at various pH values, in different water types and at various concentration levels. Main photodegradation products of acesulfame were elucidated and analyzed both in laboratory experiments and in a full-scale waterworks using UV treatment for disinfection purposes. The degradation of acesulfame was found to be independent of the pH (range 5-11) and followed pseudo first order kinetics in a concentration range between 1 µg∙L(-1) and 10 mg∙L(-1). Calculated rate constants were in the range between 5.4·10(-3)s(-1) and 7.4·10(-3)s(-1). The main photodegradation products of acesulfame were separated by ion exchange chromatography and high performance liquid chromatography and were identified as hydroxylated acesulfame and iso-acesulfame by high resolution mass spectrometry and fragmentation experiments. In the case of iso-acesulfame an intramolecular rearrangement is assumed as the transformation product has a higher polarity and different product ions after MS fragmentation compared to acesulfame. Minor transformation products were identified as amidosulfonic acid and sulfate by comparison with analytical standards. The transformation pathway was found to be transferable to drinking water production as the identified transformation products were also detected to a similar extent in fortified tap water. In a Swiss full-scale waterworks acesulfame concentrations were reduced by approximately 30% and one of the main UV transformation products could be qualitatively detected.

Approach for detecting mutagenicity of biodegraded and ozonated pharmaceuticals, metabolites and transformation products from a drinking water perspective.

Many pharmaceuticals and related metabolites are not efficiently removed in sewage treatment plants and enter into surface water. There, they might be subject of drinking water abstraction and treatment by ozonation. In this study, a systematic approach for producing and effect-based testing of transformation products (TPs) during the drinking water ozonation process is proposed. For this, two pharmaceutical parent substances, three metabolites and one environmental degradation product were investigated with respect to their biodegradability and fate during drinking water ozonation. The Ames test (TA98, TA100) was used for the identification of mutagenic activity present in the solutions after testing inherent biodegradability and/or after ozonation of the samples. Suspicious results were complemented with the umu test. Due to the low substrate concentration required for ozonation, all ozonated samples were concentrated via solid phase extraction (SPE) before performing the Ames test. With the exception of piracetam, all substances were only incompletely biodegradable, suggesting the formation of stable TPs. Metformin, piracetam and guanylurea could not be removed completely by the ozonation process. We received some evidence that technical TPs are formed by ozonation of metformin and piracetam, whereas all tested metabolites were not detectable by analytical means after ozonation. In the case of guanylurea, one ozonation TP was identified by LC/MS. None of the experiments showed an increase of mutagenic effects in the Ames test. However, the SPE concentration procedure might lead to false-positive results due to the generation of mutagenic artefacts or might lead to false-negative results by missing adequate recovery efficiency. Thus, these investigations should always be accompanied by process blank controls that are carried out along the whole ozonation and SPE procedure. The study presented here is a first attempt to investigate the significance of transformation products by a systematic approach. However, the adequacy and sensitivity of the methodology need to be further investigated. The approach of combining biodegradation and ozonation with effect-based assays is a promising tool for the early detection of potential hazards from TPs as drinking water contaminants. It can support the strategy for the evaluation of substances and metabolites in drinking water. A multitude of possible factors which influence the results have to be carefully considered, among them the selectivity and sensibility of the mutagenicity test applied, the extraction method for concentrating the relevant compounds and the biocompatibility of the solvent. Therefore, the results have to be carefully interpreted, and possible false-negative and false-positive results should be considered.