1,721,008 research outputs found
Identification of volatile compounds from bacteria by spectrometric methods in medicine diagnostic and other areas: current state and perspectives
No full textAbstract Diagnosis of bacterial infections until today mostly relies on conventional microbiological methods. The resulting long turnaround times can lead to delayed initiation of adequate antibiotic therapy and prolonged periods of empiric antibiotic therapy (e.g., in intensive care medicine). Therewith, they contribute to the mortality of bacterial infections and the induction of multidrug resistances. The detection of species specific volatile organic compounds (VOCs) emitted by bacteria has been proposed as a possible diagnostic approach with the potential to serve as an innovative point-of-care diagnostic tool with very short turnaround times. A range of spectrometric methods are available which allow the detection and quantification of bacterial VOCs down to a range of part per trillion. This narrative review introduces the application of spectrometric analytical methods for the purpose of detecting VOCs of bacterial origin and their clinical use for diagnosing different infectious conditions over the last decade. Key Points • Detection of VOCs enables bacterial differentiation in various medical conditions. • Spectrometric methods may function as point-of-care diagnostics in near future.Abstract Diagnosis of bacterial infections until today mostly relies on conventional microbiological methods. The resulting long turnaround times can lead to delayed initiation of adequate antibiotic therapy and prolonged periods of empiric antibiotic therapy (e.g., in intensive care medicine). Therewith, they contribute to the mortality of bacterial infections and the induction of multidrug resistances. The detection of species specific volatile organic compounds (VOCs) emitted by bacteria has been proposed as a possible diagnostic approach with the potential to serve as an innovative point-of-care diagnostic tool with very short turnaround times. A range of spectrometric methods are available which allow the detection and quantification of bacterial VOCs down to a range of part per trillion. This narrative review introduces the application of spectrometric analytical methods for the purpose of detecting VOCs of bacterial origin and their clinical use for diagnosing different infectious conditions over the last decade. Key Points • Detection of VOCs enables bacterial differentiation in various medical conditions. • Spectrometric methods may function as point-of-care diagnostics in near future
Personalised beta-lactam therapy: basic principles and practical approach
No full textBacterial infections are potentially life-threatening diseases requiring effective antibiotic treatment right from the outset to achieve a favourable prognosis. Therapeutic success depends on the susceptibility of the bacterial pathogen, determined by the minimum inhibitory concentration (MIC), and the concentration of the antibiotic at the focus of infection, which is influenced by drug metabolism and pharmacokinetic (PK) factors. Beta-lactams are time-dependent antibiotics. Bacterial killing correlates with the duration of the drug concentration above the MIC of the pathogen. Critical illness is associated with major PK changes. This may lead to unexpected drug concentrations and unpredictable dose requirements differing significantly from standard dosages. Emerging dosing strategies are therefore based on PK/pharmacodynamic (PD) principles. Therapeutic drug monitoring (TDM) is increasingly playing a key role in antibiotic treatment optimisation in general and in beta-lactam therapy, in particular, notably in severely ill patients. Furthermore, evidence of the superiority of continuous beta-lactam infusions over shorter administration regimens is growing. Target drug concentrations have to be defined, considering MIC values especially in pathogens with limited susceptibility. For reliable TDM results, correct pre-analytical sample handling is indispensable. Personalised, TDM-guided therapy currently offers the most promising approach to assuring that beta-lactam treatment is effective, especially in critically ill patients
Modifying a kidney injury score by including perioperative data Comparison of three predictive scores
No full textAt present, several scores have been developed to assess the risk of acute kidney injury (AKI) after cardiac surgery, and every score represents a compromise between the completeness of the factors and the early evaluation of the AKI risk. This study examined whether the predictive reliability of an AKI risk score can be significantly improved by applying not only preoperative risk factors but also intraoperative and postoperative parameters for the calculation of the score. Three scores were deduced from the data of 662 patients undergoing cardiac surgery; these were based on preoperative (score 1), pre- and intraoperative (score 2) or on pre-, intra- and postoperative parameters (score 3). Sensitivity and specificity for the prediction of an AKI were determined from a validation population comprising 529 additional patients. AKI occurred in 455 patients (38.2%). Sensitivity and specificity of the scores were 60.9% and 67.6% (score 1), 60.4% and 68.2% (score 2) and 66.8% and 64.8% (score 3). The inclusion of intra- and postoperative parameters into a predictive model does not significantly improve the ability to identify patients at risk of AKI. As scores based on preoperative parameters allow for the earliest possible risk stratification, they should be preferred in clinical practice
Evaluation of a novel noninvasive continuous core temperature measurement system with a zero heat flux sensor using a manikin of the human body
No full textReliable continuous perioperative core temperature measurement is of major importance. The pulmonary artery catheter is currently the gold standard for measuring core temperature but is invasive and expensive. Using a manikin, we evaluated the new, noninvasive SpotOn (TM) temperature monitoring system (SOT). With a sensor placed on the lateral forehead, SOT uses zero heat flux technology to noninvasively measure core temperature; and because the forehead is devoid of thermoregulatory arteriovenous shunts, a piece of bone cement served as a model of the frontal bone in this study. Bias, limits of agreements, long-term measurement stability, and the lowest measurable temperature of the device were investigated. Bias and limits of agreement of the temperature data of two SOTs and of the thermistor placed on the manikin's surface were calculated. Measurements obtained from SOTs were similar to thermistor values. The bias and limits of agreement lay within a predefined clinically acceptable range. Repeat measurements differed only slightly, and stayed stable for hours. Because of its temperature range, the SOT cannot be used to monitor temperatures below 28 degrees C. In conclusion, the new SOT could provide a reliable, less invasive and cheaper alternative for measuring perioperative core temperature in routine clinical practice. Further clinical trials are needed to evaluate these results
Continuous in-line monitoring of electrolyte concentrations in extracorporeal circuits for individualization of dialysis treatment
Full text linkOne objective of dialysis treatment is to normalize the blood
plasma electrolytes and remove waste products such as urea and creatinine
from blood. However, due to a shift in plasma osmolarity, a rapid or
excessive change of the electrolytes can lead to complications like
cardiovascular instability, overhydrating of cells, disequilibrium syndrome
and cardiac arrhythmias. Especially for critical ill patients in intensive
care unit with sepsis or multi-organ failure, any additional stress has to be
avoided. Since the exchange velocity of the electrolytes mainly depends on
the concentration gradients across the dialysis membrane between blood and
dialysate, it can be controlled by an individualized composition of dialysate
concentrations. In order to obtain a precise concentration gradient with the
individualized dialysate, it is necessary to continuously monitor the plasma
concentrations. However, with in-line sensors, the required hemocompatibility
is often difficult to achieve. In this work, we present a concept for
continuous in-line monitoring of electrolyte concentrations using
ion-selective electrodes separated from the blood flow by a dialysis
membrane, and therefore meeting the fluidic requirements for
hemocompatibility. First investigations of hemocompatibility with
reconfigured human blood show no increased hemolysis caused by the measuring
system. With this concept, it is possible to continuously measure the plasma
concentrations with a relative error of less than 0.5 %.</p
Conductive warming and insulation reduces perioperative hypothermia
No full textBackground: Perioperative hypothermia is rather common after head and neck surgery. Methods: In this prospective, randomised controlled study with 40 patients, we tested the hypothesis that the use of a new conductive warming system (PerfecTemp (TM), The Laryngeal Mask Company Limited, St. Helier, Jersey) in combination with insulation of 1.29 clo (treatment group) is better in reducing the incidence of hypothermia during and after head and neck surgery than insulation only (control group). Results: Repeated-measures analysis of variance (ANOVA) and post hoc Scheff,'s test identified a significantly higher core temperature in the treatment group at 45, 60, 75, 90, 105 and 120 min (p < 0.05). Furthermore, Fisher's exact test confirmed a lower incidence of intraoperative (3 vs. 9 patients; p = 0.03) and postoperative hypothermia (0 vs. 6 patients; p = 0.008). Conclusion: In conclusion, the combination of good thermal insulation and conductive warming is effective in preventing perioperative hypothermia during head and neck surgery. Level of Evidence: 1
Unexpectedly high incidence of hypothermia before induction of anesthesia in elective surgical patients
No full textStudy objective: Perioperative hypothermia is a frequently observed phenomenon of general anesthesia and is associated with adverse patient outcome. Recently, a significant influence of core temperature before induction of anesthesia has been reported. However, there are still little existing data on core temperature before induction of anesthesia and no data regarding potential risk factors for developing preoperative hypothermia. The purpose of this investigation was to estimate the incidence of hypothermia before anesthesia and to determine if certain factors predict its incidence. Design/setting/patients: Data from 7 prospective studies investigating core temperature previously initiated at our department were analyzed. Patients undergoing a variety of elective surgical procedures were included. Interventions/measurements: Core temperature was measured before induction of anesthesia with an oral (314 patients), infrared tympanic (143 patients), or tympanic contact thermometer (36 patients). Available potential predictors included American Society of Anesthesiologists status, sex, age, weight, height, body mass index, adipose ratio, and lean body weight. Association with preoperative hypothermia was assessed separately for each predictor using logistic regression. Independent predictors were identified using multivariable logistic regression. Main results: A total of 493 patients were included in the study. Hypothermia was found in 105 patients (21.3%; 95% confidence interval, 17.8%-25.2%). The median core temperature was 36.3 degrees C (25th-75th percentiles, 36.0 degrees C-36.7 degrees C). Two independent factors for preoperative hypothermia were identified: male sex and age (>52 years). Conclusions: As a consequence of the high incidence of hypothermia before anesthesia, measuring core temperature should be mandatory 60 to 120 minutes before induction to identify and provide adequate treatment to hypothermic patients. (C) 2016 Elsevier Inc. All rights reserved
What Determines the Efficacy of Forced-Air Warming Systems? A Manikin Evaluation with Upper Body Blankets
No full textBACKGROUND: Forced-air warming has gained acceptance as an effective means to prevent perioperative hypothermia. However, little is known about the influence Of air flow and air temperature at the nozzle and the influence of heat distribution in the blankets on the efficacy of these systems. METHODS: We conducted a manikin Study with heat flux transducers using five forced-air warming systems to determine the factors that are responsible for heat transfer from the blanket to the manikin. RESULTS: There was no relation between air temperature at the nozzle of the power unit and the resulting heat transfer. There was also no relation between the air flow at the nozzle of the power unit and the resulting heat transfer. However, all blankets performed best at high air flows above 19 L/s. The heat exchange coefficient, the mean temperature gradient between the blanket and the manikin correlated positively with the resulting heat transfer and the difference between the minimal and maximal blanket temperature correlated negatively with the resulting heat transfer. CONCLUSIONS: The efficacy of forced-air warming systems is primarily determined by the blanket. Modern power units provide sufficient heat energy to maximize the ability of the blanket to warm the patient. Optimizing blanket design by optimizing the mean temperature gradient between the blanket and the manikin (Or any other surface) with a very homogeneous temperature distribution in the blanket will enable the manufacturers to develop better forced-air warming systems.Departmental Sources; Augustine Medical; Mallinckrodt; Rusc
Accuracy of zero-heat-flux thermometry and bladder temperature measurement in critically ill patients
No full textOpen-Access-Publikationsfonds 202
Aluminium release and fluid warming: provocational setting and devices at risk
No full textBackground!#!Fluid warming, recommended for fluid rates of &gt; 500 ml h!##!Results!#!Saline solution spiked with lactate more than acetate, especially at a non neutral pH, led to high aluminium release. Next to the enFlow® device, aluminium release was observed for the Level1® device, but not for the coated ThermoSens®-device.!##!Conclusion!#!Uncoated aluminium containing fluid warming devices lead to potentially toxic levels of aluminium in heated fluids, especially in fluids with non-neutral pH containing organic acids and their salts like balanced electrolyte solutions
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