Effect of movements on the electrodermal response after a startle event.

OBJECTIVES: In this work the effect of quasi-stationary movements on the electrodermal activity (EDA) after a startle event has been investigated and evaluated. In previous EDA research there is a discrepancy between the use of controlled environment studies and daily life surveys. This paper aims to address this by expanding the knowledge about EDA in real life applications. METHODS: A minimally obtrusive body-worn measurement device was designed and produced that simultaneously records EDA and finger movements. During this study, five subjects walked at different speeds and listened to startling sound events. The EDA response to these startle events was analyzed for different walking speeds using crosscorrelograms and cumulative frequency plots. RESULTS: The measured response to the startle event is consistent with the signal characteristics described in the literature. The results show that the faster a person is walking the more the signal property of the phasic part of the EDA is approaching a uniform distribution. However, even at a walking speed of 6 km/h the effect of the startle event is statistically still visible in the EDA (p < 0.05). CONCLUSIONS: The presented work offers a good understanding of the EDA while walking at different speeds. Although the artefacts evoked by walking cannot be determined directly, information on the movement can be useful. Depending on the walking speed a measurement about the reliability of peak detection could be introduced.

On-line variable live-adjusted displays with internal and external risk-adjusted mortalities. A valuable method for benchmarking and early detection of unfavourable trends in cardiac surgery.

OBJECTIVE: Benchmarking and early detection of unfavourable trends. METHODS: We implemented a dedicated project-orientated data warehouse, which continuously supplies data for on-line computing of the variable live-adjusted displays (VLADs). To calculate the expected cumulative mortality, we used the multi-variate logistic regression model of the EuroSCORE model. In addition to the external EuroSCORE standard, we calculated a centre-specific risk score for internal standards by analysing the data of 9135 patients, which enables both internal and external comparisons. The VLADs are embedded into the multi-purpose web-based information portal, so that the physicians can investigate several types of VLADs interactively: performance of different types of surgery and individual surgeons for different time intervals. We investigated clinically important events such as modification of operative techniques and personnel changes of the team by the VLADs. RESULTS: We found transient declines in the performance curves during major changes in patient management, indicating that systemic--rather than accidental or patient related factors--were involved in the mortality risk. The internal standard line represents these clusters more clearly than the external line. We evaluated examples of how periods of increased risk could be monitored by the VLAD curves: (1) the introduction of OPCAB surgery; (2) training of surgeons; (3) staff changes and staff-related management. CONCLUSIONS: On-line VLADs based on a day-to-day updated database, displaying both internal and external standards, are a helpful visualisation tool for earlier detection of unfavourable trends. They enable the surgeon teams and clinical management to take countermeasures at an early stage.

Pervasive healthcare: paving the way for a pervasive, user-centered and preventive healthcare model.

OBJECTIVES: The aging of the population creates pressure on the healthcare systems in various ways. A massive increase of chronic disease conditions and age-related illness are predicted as the dominant forces driving the future health care. The objective of this paper is to present future research demands in pervasive healthcare with the goal to meet the healthcare challenges by paving the way for a pervasive, user-centered and preventive healthcare model. METHODS: This paper presents recent methodological approaches and proposes future research topics in three areas: i) pervasive, continuous and reliable long-term monitoring systems; ii) prevention through pervasive technology as a key element to maintain lifelong wellness; and iii) design and evaluation methods for ubiquitous, patient-centric technologies. RESULTS: Pervasive technology has been identified as a strong asset for achieving the vision of user-centered preventive healthcare. In order to make this vision a reality, new strategies for design, development and evaluation of technology have to find a common denominator and consequently interoperate. Moreover, the potential of pervasive healthcare technologies offers new opportunities beyond traditional disease treatment and may play a major role in prevention, e.g. motivate healthy behavior and disease prevention throughout all stages of life. In this sense, open challenges in future research have to be addressed such as the variability of health indicators between individuals and the manner in which relevant health indicators are provided to the users in order to maximize their motivation to mitigate or prevent unhealthy behaviors. Additionally, collecting evidence that pervasive technology improves health is seen as one of the toughest challenges. Promising approaches are recently introduced, such as "clinical proof-of-concept" and balanced observational studies. CONCLUSIONS: The paper concludes that pervasive healthcare will enable a paradigm shift from the established centralized healthcare model to a pervasive, user-centered and preventive overall lifestyle health management. In order to provide these new opportunities everywhere, anytime and to anyone, future research in the fields of pervasive sensing, pervasive prevention and evaluation of pervasive technology is inevitably needed.

[Risk stratification of patients with diabetes mellitus undergoing coronary artery bypass grafting--a comparison of statistical methods]. / Risikostratifizierung diabetischer Koronarpatienten--Statistische Methoden zur Adjustierung der Patienten-Charakteristika im Vergleich.

Among the coronary bypass patients from our Datamart database, we found a prevalence of 29.6% of diagnosed diabetics. 5.2% of the patients without a diagnosis of diabetes mellitus and a fasting plasma glucose level > 125 mg/dl were defined as undiagnosed diabetics. The objective of this paper was to compare univariate methods and techniques for risk stratification to determine, whether undiagnosed diabetes is per se a risk factor for increased ventilation time and length of ICU stay, and for increased prevalence of resuscitation, reintubation and 30-d mortality for diabetics in heart surgery. Univariate comparisons reveals that undiagnosed diabetics needed resuscitation significantly more often and had an increased ventilation time, while the length of ICU stay was significantly reduced. The significantly different distribution between the diabetics groups of 11 from 32 attributes examined, demands the use of methods for risk stratification. Both risk adjusted methods regression and matching confirm that undiagnosed diabetics had an increased ventilation time and an increased prevalence of resuscitation, while the length of ICU stay was not significantly reduced. A homogeneous distribution of the patient characteristics in the two diabetics groups could be achieved through a statistical matching method using the propensity score. In contrast to the regression analysis, a significantly increased prevalence of reintubation in undiagnosed diabetics was found. Based on an example of undiagnosed diabetics in heart surgery, the presented study reveals the necessity and the possibilities of techniques for risk stratification in retrospective analysis and shows how the potential of data collection from daily clinical practice can be used in an effective way.

[Experiences collected in more than 2,300 diabetics undergoing coronary artery bypass grafting: patients with a specific risk profile]. / Erfahrungen mit Diabetikern in der Koronarchirurgie--Patienten mit einem besonderen Risikoprofil.

BACKGROUND: The objective of this paper was to analyze demographic and clinical characteristics of diabetic patients undergoing coronary artery bypass grafting on the basis of a significant number of cases. METHODS: The data of 8,195 patients who have undergone coronary bypass operations between 1996 and 2003 were analyzed. Non-diabetic patients (no DM), oral treated diabetics (DM oral) and insulin-treated diabetics (DM insulin) were compared in terms of their pre-operative, intra-operative and post-operative characteristics. The statistical analyses were performed with the support of SPSS 11.5 under application of chi-square and student-t tests. RESULTS: In cardiosurgery, diabetics differ in various ways from non-diabetic patients. They show a significantly higher prevalence of the known cardiovascular risk factors such as raised body mass index, age and hypertension. Furthermore they present a higher prevalence of vascular comorbidity such as peripheral vascular disease and carotid disease. At the postoperative stage, cerebral dysfunction occurred more often among the diabetic patients (no DM 5.2% vs. DM oral 7.3% vs. DM insulin 10.5%; p < 0.05), they suffered from apoplexies more frequently (no DM 1.9% vs. DM oral 2.1% vs. DM insulin 3.2%; p < 0.05), and they required re-intubation more frequently (no DM 2.6% vs. DM oral 3.1% vs. DM insulin 5.6%; p < 0.05). Peri-operative mortality was highest in the group of insulin-treated diabetics (no DM 1.1% vs. DM oral 1.6% vs. DM insulin 1.8%; p < 0.05). CONCLUSION: In coronary surgery, diabetic patients represent an especially challenging patient group with an independent risk profile, who require specific consideration as far as the selection of the operative approach, on, one hand, and the post-operative follow-up, on the other hand, are concerned.

[Is age an independent predictor of mortality in cardiac surgery as postulated in EuroScore?]. / Ist das Alter eine unabhängige Determinante der Letalität in der Herzchirurgie, wie es im EuroScore behauptet wird?

The number of "older" patients undergoing cardiac surgery is steadily increasing. In the year 2000, 37% of all patients who underwent a cardiac operation in Germany were 70 years of age or older. Looking at data form our institution, we focused on the topic, whether age on its own is an independent determinant for mortality in cardiac surgery. Data from 8769 patients who underwent cardiac surgery in our institution from January 1996 until January 2002 were analyzed. For all patients, EuroScore and the corresponding age-stripped value was calculated. All recorded postoperative complications and 30-day mortality were statistically analyzed. EuroScore as well as the age-stripped EuroScore showed a significant rise with increasing age in the total number of patients as well as in the patients, who did not die during the first 30 days after the operation. The 30 day mortality and the incidence of postoperative complications increased significantly with age. While the EuroScore showed a significant age-dependent increase in patients who died within 30 days after the operation, the age-stripped EuroScore did not reveal a significant discrepancy in mortality with respect to age. Arterial hypertension, diabetes mellitus and atrial fibrillation, parameters not mentioned in EuroScore, showed significant differences among age groups. According to univariate analysis, arterial hypertension and diabetes mellitus were significant predictors of mortality. Entered into a multivariate logistic regression analysis, only diabetes mellitus achieved statistical significance. Our data and the known age-associated functional and structural changes of different organ systems show that age integrates risk factors together. In order to limit mortality in the steadily growing number of older and multi-morbid patients undergoing cardiac surgery, exceptional emphasis has to be put on patient selection and therapeutic measures to improve preoperative status.

Is there any impact of the shape of aortic end-hole cannula on stroke occurrence? clinical evaluation of straight and bent-tip aortic cannulae.

OBJECTIVE: To compare the impact of straight and bent-tip aortic cannulae on stroke occurrence, location, and severity. METHODS: Prospective data were collected on 8,129 patients (coronary artery bypass grafting (CABG) and/or valvular surgery). 'Bent-tip' aortic cannulae were used in 15.6% of cases and 'straight' end-hole cannulae in 84.4% of cases. RESULTS: There were a total of 137 strokes: right anterior 52, left anterior 39, bilateral 23, posterior 18, and location not established 5. With the use of bent-tip cannulae, the incidence of strokes was 0.9% versus 1.8% with straight cannulae (chi2, p = 0.026). Bilateral and posterior strokes occurred more often with the use of straight cannulae (chi2, p = 0.015). Straight cannulae also related to the severity of strokes (chi2, p = 0.003). CONCLUSIONS: There is an influence of the type of cannula on the occurrence, location, and severity of strokes. Straight cannulae cause significantly more often and more severe bilateral and posterior strokes than bent-tip cannulae.