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PubMed1984

[Cardiotoxicity of anthracyclines].

The cardiotoxicity of the anthracyclines, of which doxorubicin is the leading drug, manifests itself in two ways: acutely, giving rise to temporary and usually benign phenomena, and chronically, giving rise to cardiac failure which is often irreversible. The risk of cardiomyopathy is related to the total dose of anthracycline administrated. The main risk factors are, age, previous cardiac disease and mediastinal radiotherapy. The prevention of cardiomyopathy is based on the respect of empirical guide lines (interruption of anthracyclines at "threshold" cumulative doses) and on methods of detection of infra-clinical disease. Myocardial angioscintigraphy which is easier to perform than myocardial biopsy and more sensitive and specific than echocardiography seems to be the investigation of choice. The main lines of research are aimed at improving our understanding of the mechanism of the cardiomyopathy, the institution of clinical trials to detect the first signs of toxicity of continuous infusions, the improvement of the standardisation and specificity of methods of detection, better definition of alarm thresholds and the development of new, less cardiotoxic, anthracyclines and cardioprotective agents.

Acute Disease↗
PubMed2001

[Selective activation of blood pressure monitoring alarms: effect of noise pollution in the intensive care unit].

OBJECTIVE: To evaluate a selective activation of sounding alarms on non-invasive blood pressure (BP) monitoring according to the patient haemodynamic status. STUDY DESIGN: Prospective study. METHODS: Activation of alarms on BP was regulated with a protocol. Sounding alarms were either inactivated when patient's haemodynamic status was stable (group 1), or activated when it was unstable (group 2). The frequency of BP measurement was one every 15 min. For all mean BP value recorded, the following criteria were analyzed: 1) normality of the value compared to ranges 65-115 mmHg in group 1 or compared to alarm thresholds in group 2; 2) consequences on the care and therapeutic; 3) delay when an abnormal value was detected and managed after more than 15 min. RESULTS: 1,674 hours of monitoring from 42 patients, allowed the analysis of 6,695 measurements of mean BP, 3,092 in group 1 and 3,603 in group 2. In group 1, 2,822 measurements were considered as normal and 3,094 measures in group 2. Eight measurements had consequences on therapeutic in group 1, with only one with delay in care giving. 287 measurements had consequences on therapeutic in group 2, 8 with delay in care giving. Six per cent of abnormal measurements in group 2 were managed with delay. This protocol reduced by 52% the production of sounding alarms on BP, without noxious effects for the patients. CONCLUSION: Selective activation of sounding alarms on BP, according to the patient haemodynamic status, reduced noise pollution and could be one solution to improve monitoring efficiency in intensive care unit.

France↗
PubMed1997

Voluntary breath holding: not a suitable probe of the suffocation alarm in panic disorder.

Voluntary breath-holding duration was investigated in patients with panic disorder, patients with a mood disorder, and normal controls. There were no differences in mean breath-holding durations, but the pattern of scores was different among groups. Furthermore, the scores were influenced by motivational and cognitive factors. It is argued that voluntary breath-holding is not a suitable test to measure carbon dioxide sensitivity or suffocation alarm threshold in panic disorder.

Adolescent↗
PubMed2002

Factors influencing mass concentration and chemical composition of fine aerosols during a PM high pollution episode.

Results obtained during a winter field campaign for the fine fractions of particulate matter are presented. A high pollution episode together with an analysis of the main factors, which influence accumulation of pollutants is described. The measurement campaigns were carried out simultaneously at two sites in Northern Italy, Milan and Erba, during the winter of 2000. The daily variability in the mass concentration values and PM2.5/PM10 ratios appeared to be strongly dependent upon meteorological and atmospheric stability conditions and, in particular, wind regimes. During the intensive field campaign a high-pollution episode occurred that led to TSP and fine fraction concentrations well above the attention and alarm thresholds, reaching values of up to 200-250 microg m(-3). The elemental concentrations were determined by ED-XRF analysis. The elemental composition of the particulate matter indicated that crustal matter oxides (soil dust) were the main component in particles with aerodynamic diameter d(ae) > 10 microm. They were an important part also in particles with 2.5 < d(ae) < 10 microm, but strongly decreased in particles with d(ae) < 2.5 microm. In the finer fraction sulphates nitrogen and carbon compounds played a major role. The temporal patterns of mass and elemental concentrations, as well as the main components of PM were very similar at the two sites. The high-pollution episode was recorded at many locations in the Po plain, highlighting the role of meteorology and thermodynamic atmospheric conditions on pollution build-up on a large area.

Aerosols↗
PubMed2003

A quantitative method for optimized placement of continuous air monitors.

Alarming continuous air monitors (CAMs) are a critical component for worker protection in facilities that handle large amounts of hazardous materials. In nuclear facilities, continuous air monitors alarm when levels of airborne radioactive materials exceed alarm thresholds, thus prompting workers to exit the room to reduce inhalation exposures. To maintain a high level of worker protection, continuous air monitors are required to detect radioactive aerosol clouds quickly and with good sensitivity. This requires that there are sufficient numbers of continuous air monitors in a room and that they are well positioned. Yet there are no published methodologies to quantitatively determine the optimal number and placement of continuous air monitors in a room. The goal of this study was to develop and test an approach to quantitatively determine optimal number and placement of continuous air monitors in a room. The method we have developed uses tracer aerosol releases (to simulate accidental releases) and the measurement of the temporal and spatial aspects of the dispersion of the tracer aerosol through the room. The aerosol dispersion data is then analyzed to optimize continuous air monitor utilization based on simulated worker exposure. This method was tested in a room within a Department of Energy operated plutonium facility at the Savannah River Site in South Carolina, U.S. Results from this study show that the value of quantitative airflow and aerosol dispersion studies is significant and that worker protection can be significantly improved while balancing the costs associated with CAM programs.

Aerosols↗
PubMed2006

Review of syndromic surveillance: implications for waterborne disease detection.

Syndromic surveillance is the gathering of data for public health purposes before laboratory or clinically confirmed information is available. Interest in syndromic surveillance has increased because of concerns about bioterrorism. In addition to bioterrorism detection, syndromic surveillance may be suited to detecting waterborne disease outbreaks. Theoretical benefits of syndromic surveillance include potential timeliness, increased response capacity, ability to establish baseline disease burdens, and ability to delineate the geographical reach of an outbreak. This review summarises the evidence gathered from retrospective, prospective, and simulation studies to assess the efficacy of syndromic surveillance for waterborne disease detection. There is little evidence that syndromic surveillance mitigates the effects of disease outbreaks through earlier detection and response. Syndromic surveillance should not be implemented at the expense of traditional disease surveillance, and should not be relied upon as a principal outbreak detection tool. The utility of syndromic surveillance is dependent on alarm thresholds that can be evaluated in practice. Syndromic data sources such as over the counter drug sales for detection of waterborne outbreaks should be further evaluated.

Animals↗
PubMedDate not supplied

Massive unilateral hydrothorax as the only clinical manifestation of ovarian hyperstimulation syndrome.

We describe the case of a 36 old woman with a right massive hydrothorax resulting from Controlled Ovarian Hyperstimulation (COH) for infertility. This complication is defined as Ovarian Hyperstimulation Syndrome (OHSS) which usually includes abdominal pain, nausea and ascites, rarely involving the respiratory apparatus. The usual determining factors of OHSS are the presence of high serum estradiol levels and pregnancy. In the case that we describe the serum estradiol levels during COH were monitored and were slightly higher than the COH alarm threshold and the patient was not pregnant.

Adult↗
PubMed1992

[Incidence of nosocomial infections in a military hospital].

Over a 2-year period, 479 cases of nosocomial infections were identified in our hospital by a surveillance method based on the bacteriological laboratory results. The monthly incidence rate ranged from 1.8 to 4 percent of all in-patients. With this method, a 2 percent background noise and a 4 percent alarm threshold could be defined. The most frequent nosocomial infections were urinary tract infections (77 percent), purulent skin infections (12 percent) and septicaemias (10 percent). Compared during 15 days with the most sensitive surveillance method of the National Nosocomial Infections Surveillance System, our method proved insufficient to detect nosocomial lung infections and superficial surgical wound infections. On the other hand, it was highly satisfactory to watch for urinary tract infections and septicaemias. Improvements that would not put a heavy burden on the work of clinical departments are suggested.

Adolescent↗
PubMed2005

Monitoring respiratory mechanics during mechanical ventilation: where do the signals come from?

Graphical patient data have become essential to the understanding and management of ventilator-dependent patients. These electronically generated data often reveal clues to subtle complications that, if corrected, could lead to improved patient-ventilator harmony. The apparent precision of the waveforms and the 3- or 4-place display of numeric data imply high accuracy. Laboratory devices and equipment, with their required certification, generally exhibit accuracies of approximately 2% for flow and significantly less than 1% for pressure. But the cost constraints placed on hospital-grade medical equipment dictate the use of commercial sensors-transducers, which means that pressure measurements will range between 3% and 5% of reading, and flow measurements will range between 6% and 10% (+/- 3 standard deviations of the mean). Other direct and indirect influences, such as temperature, humidity, absolute pressure, system pressure, type of gas, contamination, and myriad additional effects further interfere with the transformation of the variable of interest into an electrically equivalent signal. The abundance of viewable information pertinent to the management of the ventilated patient can be traced to the availability of the many types of transducers combined with microprocessor electronics. The process of capturing a variable of interest (sensing and signal transduction), converting it to a digitized electronic signal (analog-to-digital-conversion), operating on that signal (such as for control of the breathing algorithm and checking for violation of alarm thresholds), and finally converting it back to an analog signal that appears on a monitor generally receives scant appreciation. The process, however, lies at the core of data management in modern ICU ventilators.

Algorithms↗
PubMed1992

[Time-series analysis applied to nosocomial infection].

BACKGROUND: In this study we introduce a new view of hospital infection, to apply time series techniques to it. Our objective is to complement hospital infection's epidemiological surveillance by means of obtaining alert and alarm thresholds that make easy to the epidemiologist the decision of intervention, in case they are exceeded. METHODS: We have used the classic time series analysis described by Rumeau-Rouquette, and ARIMA (Autoregresive Integrated Moving Average) models developed by Box and Jenkins. The study focus on three hospital units: one intensive care, one long term care and one surgical unit. The nosocomial infection intervals have been calculated with a 68% (1SD) and 95% (2SD) confidence levels. RESULTS: We detect an ascending general trend in the last two units, without the detection of seasonal variations. Two ARIMA (1, 0, 0) models we obtained for surgery and long term care, discarding other better adjusted models, more complex and difficult to obtain, but with no real advantage in prediction power. Confidence intervals were calculated with both methods. We did not find general trend and seasonal variations for intensive care unit. No model was considered valid, because of its high random component. The nosocomial infection intervals have been calculated with mean +/- 1SD and mean +/- 2SD. CONCLUSIONS: We think that more precise knowledge of hospital infection, with a high random component in our study, can be in addition useful to assign priority to human and material resources.

Analysis of Variance↗
PubMed1987

A new conventional and high-frequency ventilator for small animals.

A pressure limited, time controlled ventilator has been designed especially for studies on experimental animals with severe respiratory distress syndrome (SRDS). Inspiration: Expiration (I:E) ratio (1:99-99:1) and frequency can be changed independently. Frequency ranged from 1 to 199/min in conventional ventilation (CV), while in high-frequency jet ventilation (HFJV) from 1 to 30 Hz. The gas delivery system consists of 3 magnetic valves (inspiration, expiration and HFJV, respectively) to ensure superposition of CV with HFJ or to use them separately. A monitoring unit switches off inspiration gas sources during HFJV if intratracheal pressure exceeds the alarm threshold. The device has been used in the following animal models: premature newborn rabbits with surfactant deficient lungs, emphysematous rats and guinea pigs as well as dogs and rabbits with SRDS due to lung lavage. Ventilation was most effective with an I:E ratio of 4:1 during pressure controlled CV, whereas during HFJV optimum gas exchange could be maintained with an I:E ratio of 1:4 and a frequency of 15 Hz in beagle dogs and 10 Hz in rabbits, respectively.

Animals↗
PubMed1994

Monitor-driven data visualization: SmartDisplay.

Exhaustive display of all available clinical data, particular in data-rich environments like the intensive care unit, can easily overwhelm the ability of clinicians to comprehend the clinical status and evolution of their patients and may reduce their ability to detect pathological trends in a reliable and timely manner. SmartDisplay is a system we have designed that restricts the data sets displayed to time-lines of those parameters that are relevant to the patient context and to the particular care provider. The relevance criteria are provided by monitoring programs which may range in complexity from simple threshold alarms to full-fledged diagnostic engines. SmartDisplay can specify which parameters to display and the time intervals during which they should be displayed.

Data Display↗
PubMed1976

Effects of stimulus presentation and instructions on pure-tone thresholds and false-alarm responses.

The effects of three instructional sets (conventional Carhart-Jerger, strict, and lax) and of two stimulus presentation methods (continuous tones, pulsed tones) on pure-tone thresholds and false-alarm responses were determined for 20 male subjects. False alarms were tallied during hearing measurement periods and during 30-second time-out periods totaling nine minutes of time-out per subject. Results showed that 50% of the subjects made false-alarm responses to some extent at 250, 1000, and 4000 Hz. Instructions and stimulus mode, along with frequency, affected the number of false alarms, but thresholds under the experimental conditions were unchanged. It is suggested that a method for assessing and controlling false alarms is an important clinical consideration.

Acoustic Stimulation↗
PubMed1991

Methods for estimating infant thresholds.

Detection thresholds for 1000-Hz, 16-ms tone bursts were estimated for 3- and 6-month-old infants and for young adults. The test procedure used was the observer-based psychoacoustic procedure. Thresholds were estimated using two different adaptive procedures and the method of constant stimuli. There was little difference among the average thresholds determined by any of these techniques. The least variable thresholds were obtained in the method of constant stimuli. In addition, 10 infants at each age completed two 30-trial blocks of trials in the method of constant stimuli; 22 adults completed 8 blocks of 30 trials. For 3- and 6-month-olds and for adults, there was no significant change in average threshold between blocks. Individual 6-month-olds' thresholds rarely changed by more than 5 dB between blocks, and the correlation between the thresholds obtained in the two blocks was significant. Individual 3-month-olds' thresholds, however, sometimes changed by as much as 10 dB between blocks, and the correlation between first and second block threshold was not significant. The effects of response bias on threshold were assessed by examining receiver operating characteristic plots of hit and false alarm rates at threshold and the correlation between false alarm rate and threshold. Although there was some variability in response bias, infant/observer teams tended to respond in an unbiased fashion. In one of the adaptive procedures only, false alarm rate was significantly correlated with threshold. In all procedures, the exclusion of infants with high false alarm rates changed the average thresholds obtained by less than 5 dB.(ABSTRACT TRUNCATED AT 250 WORDS)

Audiometry, Pure-Tone↗
PubMed2006

Method for detecting the disconnection of an extracorporeal device using a patient's endogenous electrical voltages.

Tubing (especially venous) disconnections using pumped devices cause significant hemorrhage, and current monitoring techniques are imperfect because they rely on intraluminal pressure changes. We devised a passive detection method based on a patient's electrical voltages being transmitted via blood tubing to our alarm circuit. As the arterial and venous access sites are in close proximity, the signals are nearly identical during connection, and markedly different with disconnection. We built a prototype and tested it in vitro with saline and during hemodialysis treatments (n=7). The connection status is determined by examining the difference between endogenous voltages in the blood tubing from and to the patient, and when it exceeds a threshold an alarm condition is triggered. We tested for possible confounding by an electrical shunt through the dialyzer and determined that pathway had an impedance approximately three times (>350 kOmega) that of the tubing to the patient. As the roller blood-pump periodically occluded the tubing, the resultant intermittent very high impedance prevented that potential shunting problem and improved the sensitivity of our device. Disconnections were detectable at various bloodline sites (needles, sampling ports, drip chambers). Thus, the circuit's sensors can be placed remotely at the dialysis machine, with electrical continuity to blood made by inexpensive conductive elements at the tubing wall or drip chambers. Appropriate threshold and noise-eliminating circuitry, as well as alarm states that alert the staff and stop the blood pump, make our prototype a promising low-cost safety enhancement.

Blood Pressure↗
PubMed2002

Continuum of impulsiveness caused by auditory masking.

OBJECTIVE: Impulsivity is a hallmark of attention deficit/hyperactivity disorder (ADHD). Various auditory masking procedures can quantify the impulsivity caused by distracting background sounds. This study compares the impulsiveness and distraction caused by informational masking (unpredictable tones) with previously published data on central masking (contralateral noise) in children with and without ADHD. METHODS: Twenty-six normal and 14 children diagnosed as having ADHD (combined type), all between the ages of 7 and 13, indicated whether they heard a 512-ms, 500-Hz pure tone in a single-interval task under conditions of informational masking and in quiet. The masker consisted of 10 randomly selected frequencies between 1,000 and 2,500 Hz presented simultaneously at an overall level of 60 dB SPL. A maximum-likelihood method estimated thresholds and false alarm rates. RESULTS: There were no differences due to ADHD in thresholds or false alarm rates either with informational masking or in quiet. With informational masking, normal children had high false alarm rates, similar to those from children with ADHD under central masking. With informational masking, all children tended to say a stimulus was present when it was not. CONCLUSIONS: All children behave impulsively under some conditions. Pediatric patients with attention disorders can thus be reassured that impulsiveness with unpredictable background sounds is normal, to some extent. Response biases of children with ADHD may only diverge from normal in situations where distracting external stimuli have an intermediate level of predictability. A previous study showed that with central masking, children with ADHD are more impulsive than normal. There appears to be a limit to the uncertainty in auditory masking that can be tolerated by children. Children with ADHD become impulsive at lower levels of uncertainty than normal. Increasing the predictability of distracting background sounds may thus improve the performance of children with ADHD. Informational masking may, for normal listeners, mimic something of what it is like to have an attention deficit. ADHD can be profitably studied with auditory tasks.

Acoustic Stimulation↗
PubMed1988

Computer-assisted Doppler monitoring to enhance detection of air emboli.

Currently, two of the most sensitive clinical approaches commonly used to monitor for venous air embolism, i.e., precordial Doppler audio and capnography, require the attention of the anesthesiologist's eye or ear, which is a distraction from other aspects of care. To assess the feasibility of allowing the computer to relieve the necessity for continuous human monitoring, we developed a computer algorithm for monitoring the precordial Doppler audio. This algorithm extracted (1) the amplitude of certain higher-frequency components of the Doppler audio, (2) a measure of the average value of the envelope of Doppler audio, and (3) the ratio between the average value of the Doppler envelope and the amount of envelope signal variation at heart rate frequency and its multiples. These three features were monitored by an adaptive pattern recognition algorithm that compared each new value for each feature with the previously developed mean and standard deviation for that feature. If the changes in the three features exceeded a detection threshold, an alarm (indicating suspected air embolism) was activated. Implemented as a prototype system, the algorithm was given preliminary testing in 2 dogs and activated alarms at levels of air well below those reported to cause clinically significant hemodynamic changes in dogs. While decreasing the distraction for the anesthesiologist, this early prototype alarm system alerts its user to the need for analysis of the Doppler signals when it senses an air embolus.

Algorithms↗
PubMed2004

Impact of posture and fixation technique on impedance spectroscopy used for continuous and noninvasive glucose monitoring.

Impedance spectroscopy allows for the assessment of changes in the permittivity and conductivity of erythrocyte cell membranes, induced by blood glucose variations. This study was performed to evaluate the potential influence of motion-induced microvascular blood flow variations from different forearm postures on the PENDRA (Pendragon Medical AG, Zürich, Switzerland) signal. Fifteen volunteers without diabetes were included (seven female, eight male, mean +/- SD age 33.3 +/- 9.9 years, body mass index 24.8 +/- 3.0 kg/m(2)). PENDRA devices were fixed at both upper extremities with different fixation techniques (bracelet and adhesive tape). Standardized position changes of the upper extremities were performed to induce variations in cutaneous microcirculation, which were assessed by laser-Doppler-fluxmetry with different probe temperatures on the forearm. Changes in microcirculation were seen in some of the different motion procedures: supine to hanging, 61.1 +/- 29.9 arbitrary units (AU) to 46.2 +/- 24.8 AU at 37 degrees C and 15.9 +/- 13.0 AU to 13.4 +/- 10.1 at skin temperature (P < 0.01 for both probes); supine to upright, 80.5 +/- 55.4 AU to 74.9 +/- 43.8 AU (not significant) at 37 degrees C and 18.7 +/- 16.8 AU to 20.9 +/- 16.1 AU at skin temperature (P < 0.01). An initially observed subtle influence of microcirculation variations on the impedance signal was minimized when the device was fixed by both bracelet and tape. Other influencing factors (such as temperature, local anatomy, etc.) are addressed in the complex calibration procedure. Well-educated patients might be the best candidates for first using the device for continuous glucose monitoring. They may especially benefit from the trend indication and the hypoglycemia/hyperglycemia threshold and alarm functions.

Adult↗