Continuous intravascular blood gas monitoring: development, current techniques, and clinical use of a commercial device

This review focuses on the development, current techniques, and clinical use of continuous intravascular blood gas monitoring (CIBM) devices in anaesthesia and intensive care. The operating principles, range of application, performance, limitations, costs, and impact on patient treatment and outcome, are discussed. Studies of early and currently available CIBM devices were analysed. At present, the Paratrend 7+® (PT7+®) for adults and Neotrend™ (NT™) for newborns are the only commercially available CIBM systems. The PT7+® contains three optical sensors to measure Po2, Pco2 and pH, as well as a thermocouple to measure temperature. The NT™ is a modification of the PT7+® to continuously monitor Po2, Pco2, pH and temperature in newborns. Under laboratory conditions, good performance over a wide range of blood gas values was observed with the Paratrend 7® (PT7®). Performance in the clinical setting was not as satisfactory, especially for Po2 values. However, the performance and accuracy of CIBM devices appear to be sufficient for clinical use and they are being used clinically in selected patient groups. Several factors affecting the performance of CIBM are considered. Br J Anaesth 2003: 91; 397-40

Continuous intravascular blood gas monitoring: development, current techniques, and clinical use of a commercial device

This review focuses on the development, current techniques, and clinical use of continuous intravascular blood gas monitoring (CIBM) devices in anaesthesia and intensive care. The operating principles, range of application, performance, limitations, costs, and impact on patient treatment and outcome, are discussed. Studies of early and currently available CIBM devices were analysed. At present, the Paratrend 7+® (PT7+®) for adults and Neotrend™ (NT™) for newborns are the only commercially available CIBM systems. The PT7+® contains three optical sensors to measure Po2, Pco2 and pH, as well as a thermocouple to measure temperature. The NT™ is a modification of the PT7+® to continuously monitor Po2, Pco2, pH and temperature in newborns. Under laboratory conditions, good performance over a wide range of blood gas values was observed with the Paratrend 7® (PT7®). Performance in the clinical setting was not as satisfactory, especially for Po2 values. However, the performance and accuracy of CIBM devices appear to be sufficient for clinical use and they are being used clinically in selected patient groups. Several factors affecting the performance of CIBM are considered. Br J Anaesth 2003: 91; 397-40

Multicentre evaluation of a new point-of-care test for the determination of NT-proBNP in whole blood

Background: The Roche CARDIAC proBNP point-of-care (POC) test is the first test intended for the quantitative determination of N-terminal pro-brain natriuretic peptide (NT-proBNP) in whole blood as an aid in the diagnosis of suspected congestive heart failure, in the monitoring of patients with compensated left-ventricular dysfunction and in the risk stratification of patients with acute coronary syndromes. Methods: A multicentre evaluation was carried out to assess the analytical performance of the POC NT-proBNP test at seven different sites. Results: The majority of all coefficients of variation (CVs) obtained for within-series imprecision using native blood samples was below 10% for both 52 samples measured ten times and for 674 samples measured in duplicate. Using quality control material, the majority of CV values for day-to-day imprecision were below 14% for the low control level and below 13% for the high control level. In method comparisons for four lots of the POC NT-proBNP test with the laboratory reference method (Elecsys proBNP), the slope ranged from 0.93 to 1.10 and the intercept ranged from 1.8 to 6.9. The bias found between venous and arterial blood with the POC NT-proBNP method was ≤5%. All four lots of the POC NT-proBNP test investigated showed excellent agreement, with mean differences of between −5% and +4%. No significant interference was observed with lipaemic blood (triglyceride concentrations up to 6.3mmol/L), icteric blood (bilirubin concentrations up to 582μmol/L), haemolytic blood (haemoglobin concentrations up to 62mg/L), biotin (up to 10mg/L), rheumatoid factor (up to 42IU/mL), or with 50 out of 52 standard or cardiological drugs in therapeutic concentrations. With bisoprolol and BNP, somewhat higher bias in the low NT-proBNP concentration range (<175ng/L) was found. Haematocrit values between 28% and 58% had no influence on the test result. Interference may be caused by human anti-mouse antibodies (HAMA) types 1 and 2. No significant influence on the results with POC NT-proBNP was found using volumes of 140-165μL. High NT-proBNP concentrations above the measuring range of the POC NT-proBNP test did not lead to false low results due to a potential high-dose hook effect. Conclusions: The POC NT-proBNP test showed good analytical performance and excellent agreement with the laboratory method. The POC NT-proBNP assay is therefore suitable in the POC setting. Clin Chem Lab Med 2006;44:1269-7

Effect of Intensive Training on Mood With No Effect on Brain-Derived Neurotrophic Factor

Purpose Monitoring mood state is a useful tool for avoiding non-functional overreaching (NFOR). Brain derived neurotrophic factor (BDNF) is implicated in stress-related mood disorders. The purpose of the present study was to investigate the impact of intensified training-induced mood disturbance on plasma BDNF concentrations at rest and in response to exercise.&nbsp; Methods Eight cyclists performed 1 week of normal (NT), 1 week of intensified (INT) and 1 week of recovery (REC) training. Fasted blood samples were collected before and after exercise, on day 7 of each training week and were analyzed for plasma BDNF and cortisol concentrations. A 24-item Profile Of Mood State questionnaire was administered on day 7 of each training week and global mood score (GMS) was calculated. Results Time trial performance was impaired during INT (p=0.01) and REC (p=0.02) compared with NT. Basal plasma cortisol (NT=153&plusmn;16 ng/ml, INT=130&plusmn;11 ng/ml, REC=150&plusmn;14 ng/ml) and BDNF (NT=484&plusmn;122 pg/ml, INT=488&plusmn;122 pg/ml, REC=383&plusmn;56 pg/ml) concentrations were similar between training conditions. Likewise, similar exercise-induced increases in cortisol and BDNF concentrations were observed between training conditions. GMS was 32% greater during INTvs.NT (P&lt;0.001). Conclusion Consistent with a state of functional overreaching (FOR), impairments in performance and mood state with INT were restored after one week of REC. These results support evidence that mood changes before plasma BDNF concentrations as a biochemical marker of FOR and that cortisol is not a useful marker for predicting FOR

Process Monitoring on Sequences of System Call Count Vectors

We introduce a methodology for efficient monitoring of processes running on hosts in a corporate network. The methodology is based on collecting streams of system calls produced by all or selected processes on the hosts, and sending them over the network to a monitoring server, where machine learning algorithms are used to identify changes in process behavior due to malicious activity, hardware failures, or software errors. The methodology uses a sequence of system call count vectors as the data format which can handle large and varying volumes of data. Unlike previous approaches, the methodology introduced in this paper is suitable for distributed collection and processing of data in large corporate networks. We evaluate the methodology both in a laboratory setting on a real-life setup and provide statistics characterizing performance and accuracy of the methodology.Comment: 5 pages, 4 figures, ICCST 201

Hoops and Barns: a new dilemma for Sosa

This paper critically assesses Sosa’s normative framework for performances as well as its application to epistemology. We first develop a problem for one of Sosa’s central theses in the general theory of performance normativity according to which performances attain fully desirable status if and only if they are fully apt. More specifically, we argue that given Sosa’s account of full aptness according to which a performance is fully apt only if safe from failure, this thesis can’t be true. We then embark on a rescue mission on behalf of Sosa and work towards a weakened account of full aptness. The key idea is to countenance a distinction between negligible and non-negligible types of risk and to develop an account of full aptness according to which even performances that are endangered by risk can be fully apt, so long as the risk is of a negligible type. While this alternative account of full aptness solves the problem we developed for Sosa earlier on, there is also bad news for Sosa. When applied to epistemology, the envisaged treatment of barn façade cases as cases in which the agent falls short of fully apt belief will no longer work. We show that, as a result, Sosa faces a new version of a familiar dilemma for virtue epistemology. Either he construes full aptness as strong enough to get barn façade cases right in which case his view will run right into the problem we develop. Or else he construes full aptness as weak enough to avoid this problem but then he will not be able to deal with barn façade cases in the way envisaged

Tracking Adaptation and Measuring Development in Kenya

Tracking Adaptation and Measuring Development (TAMD) is a twin-track framework that evaluates adaptation success as a combination of how widely and how well countries or institutions manage climate risks (Track 1) and how successful adaptation interventions are in reducing climate vulnerability and in keeping development on course (Track 2). With this twin-track approach, TAMD can be used to assess whether climate change adaptation leads to effective development, and also how development interventions can boost communities' capacity to adapt to climate change. Importantly, TAMD offers a flexible framework that can be used to generate bespoke frameworks for individual countries that can be tailored to specific contexts and used at different scales. This report compiles the results of TAMD feasibility testing phase in Kenya

GPS-Based Evaluation of Activity Profiles in Elite Downhill Mountain Biking and the Influence of Course Type

This study aimed to profile the activity patterns of elite downhill (DH) mountain bikers during off-road descending, and to determine the influence of course types on activity patterns. Six male elite DH mountain bikers (age 20 ± 2 yrs; stature 178.8 ± 3.1 cm; body mass 75.0 ± 3.0 kg) performed single runs on one man-made (MM) and one natural terrain (NT) DH courses under race conditions. A 5 Hz global positioning systems (GPS) unit, including a 100 Hz triaxial accelerometer, was positioned in a neoprene harness between the C7 and T2 vertebrae on each rider. GPS was used to determine the temporal characteristics of each run for velocity, run time, distance, effort, heart rate (HR), rider load (RLd) which reflects instantaneous rate of change in acceleration, and accumulated rider load (RLdAcc), which reflects change in acceleration over the event duration. Significant differences were found between NT and MM courses for mean velocity (p<.001), peak velocity (p=.014), mean RLd (p=.001) and peak RLd (p=.002). Significant differences were also found both within and between courses for all velocity parameters, when analysed by intensity zone (p<.05). No significant differences were found between courses for HR parameters by zone, though significant differences were revealed between HR zones within courses (p<.05). This study indicates that course terrain has a significant impact on the activity profiles of DH and that GPS can provide a practical means of monitoring these differences in activity

Anthracycline-Induced Cardiotoxicity: Cardiac Monitoring by Continuous Wave-Doppler Ultrasound Cardiac Output Monitoring and Correlation to Echocardiography

Background: Anthracyclines are agents with a well-known cardiotoxicity. The study sought to evaluate the hemodynamic response to an anthracycline using real-time continuous-wave (CW)-Doppler ultrasound cardiac output monitoring (USCOM) and echocardiography in combination with serum biomarkers. Methods: 50 patients (26 male, 24 female, median age 59 years) suffering from various types of cancer received an anthracycline-based regimen. Patients' responses were measured at different time points (T0 prior to infusion, T1 6 h post infusion, T2 after 1 day, T3 after 7 days, and T4 after 3 months) with CW-Doppler ultrasound (T0-T4) and echocardiography (T1, T4) for hemodynamic parameters such as stroke volume (SV; SVUSCOM ml) and ejection fraction (EF; EFechocardiography%) and with NT-pro-BNP and hs-Troponin T (T0-T4). Results: During the 3-month observation period, the relative decrease in the EF determined by echocardiography was -2.1% (Delta T0-T4, T0 71 +/- 7.8%, T4 69.5 +/- 7%, p = 0.04), whereas the decrease in SV observed using CW-Doppler was -6.5% (Delta T0-T4, T0 54 +/- 19.2 ml, T4 50.5 +/- 20.6 ml, p = 0.14). The kinetics for serum biomarkers were inversely correlated. Conclusions: Combining real-time CW-Doppler USCOM and serum biomarkers is feasible for monitoring the immediate and chronic hemodynamic changes during an anthracycline-based regimen; the results obtained were comparable to those from echocardiography