Capacitive ECG system with direct access to standard leads and body surface potential mapping

[Subjective certainty to increase the acceptance of automated and connected driving]

An important factor for the acceptance and thus the spread of automated and connected driving (ACD) is the degree of subjective uncertainty that users experience when interacting with automated vehicles. Subjective uncertainties always occur when people are not able to predict the further course of a situation or future events due to lack of experience or information. If such uncertainties occur during the use of automated vehicles, the development of trust and thus acceptance of this technology is impaired by the negative emotions accompanying subjective uncertainties. Within the AutoAkzept project (which full title translates to: Automation without uncertainty to increase the acceptance of automated and connected driving), solutions for user-focused automation have been developed that put vehicle occupants at the center of system development. User-focused systems take into account two basic human needs in human-machine interaction, the need to understand and the need to be understood. For this purpose, user-focused systems use different sensors to detect subjective uncertainties and their influencing factors in real time, integrate this information with context data and make adjustments that reduce subjective uncertainties. The systemic adaptations of user-focused systems follow a holistic approach that includes the levels of vehicle guidance, interior adaptation and information presentation as well as target guidance are included. By reducing or avoiding subjective uncertainties, the project developments contribute to a positive, comfortable user experience and help to increase the acceptance of ACD. This paper presents research results of AutoAkzept on the topics of user state and activity modelling as well as needs-based adaptation strategies, which represent key components for the implementation of user-focused automation.

Monitoring of Cardiorespiratory Signals Using Thermal Imaging: A Pilot Study on Healthy Human Subjects

Heart rate (HR) and respiratory rate (RR) are important parameters for patient assessment. However, current measurement techniques require attachment of sensors to the patient’s body, often leading to discomfort, stress and even pain. A new algorithm is presented for monitoring both HR and RR using thermal imaging. The cyclical ejection of blood flow from the heart to the head (through carotid arteries and thoracic aorta) leads to periodic movements of the head; these vertical movements are used to assess HR. Respiratory rate is estimated by using temperature fluctuations under the nose during the respiratory cycle. To test the viability and feasibility of this approach, a pilot study was conducted with 20 healthy subjects (aged 18⁻36 and 1 aged 50 years). The study consisted of two phases: phase A (frontal view acquisitions) and phase B (side view acquisitions). To validate the results, photoplethysmography and thoracic effort (piezoplethysmography) were simultaneously recorded. High agreement between infrared thermography and ground truth/gold standard was achieved. For HR, the root-mean-square errors (RMSE) for phases A and B were 3.53 ± 1.53 and 3.43 ± 1.61 beats per minute, respectively. For RR, the RMSE between thermal imaging and piezoplethysmography stayed around 0.71 ± 0.30 breaths per minute (phase A). This study demonstrates that infrared thermography may be a promising, clinically relevant alternative for the assessment of HR and RR.

Novel flexible Dry multipin electrodes for EEG: Signal quality and interfacial impedance of Ti and TiN coatings

Conventional Silver/Silver-Chloride electrodes are inappropriate for routine high-density EEG and emerging new fields of application like brain computer interfaces. A novel multipin electrode design is proposed. It enables rapid and easy application while maintaining signal quality and patient comfort. The electrode design is described and impedance and EEG tests are performed with Titanium and Titanium Nitride coated electrodes. The results are compared to conventional reference electrodes in a multi-volunteer study. The calculated signal parameters prove the multipin electrode concept to reproducibly acquire EEG signal quality comparable to Ag/AgCl electrodes. The promising results encourage further investigation and can provide a technological base for future preparation-free multichannel EEG systems.

Evaluation of a novel portable capacitive ECG system in the clinical practice for a fast and simple ECG assessment in patients presenting with chest pain: FIDET (Fast Infarction Diagnosis ECG Trial)

Background

Electrocardiogram (ECG) assessment plays a crucial role in patients presenting with chest pain and suspected acute coronary syndrome (ACS). In a pilot study, we previously evaluated a capacitive ECG system (cECG) as a novel ECG technique for a fast and simple ECG assessment in patients with ST-elevation myocardial infarction (STEMI). In a next step, the sensitivity and specificity of this novel ECG technique have to be assessed in patients with ACS.

Hypothesis

The Fast Infarction Diagnosis ECG Trial (FIDET) is a prospective, bi-center, observer-blinded noninferiority study to evaluate the cECG compared to the conventional ECG (kECG) in the clinical practice for ECG assessment in consecutive patients presenting with suspected ACS.

Methods

In 250 patients who were admitted to the hospital, because of an ACS [including STEMI and non-ST-elevation acute coronary syndrome (NSTE-ACS)], both a kECG and a cECG recording were performed within a time lag of less than 10 min.

End points

The primary end point will be sensitivity and specificity of the cECG compared to the kECG in diagnosing a STEMI with a margin of noninferiority of 7.5 %. Secondary end points include sensitivity and specificity of the cECG compared to the kECG in diagnosing an NSTE-ACS, safety of the cECG system (adverse event, serious adverse event and suspected unexpected serious adverse reaction), parameters of the ECG measurement (PQ-interval, QT-interval, ST-amplitude and heart rate) and measurement duration of the two methods.

Conclusion

FIDET is designed as a noninferiority study to show that a novel cECG system is suitable for the diagnosis of myocardial infarction in the clinical context and might even have benefits, for example by offering a faster and easier ECG assessment.

First clinical evaluation of a novel capacitive ECG system in patients with acute myocardial infarction

Objective

The ECG plays a central role in the rapid diagnosis of acute myocardial infarctions (MI). In haemodynamically instable patients, adhesion of electrodes sometimes is difficult and assessing ECGs through layers of clothes has not been done so far. A novel capacitive measurement of ECG signals is possible without skin contact. Whether this technical innovation can be used in patients with MI is unclear.

Methods

We evaluated a capacitive ECG system (cECG) in patients with anterior and inferior ST elevation MI (STEMI) as compared to patients without ST elevations in anterior and inferior leads. The cECG was assessed using a sensor array consisting of 15 electrodes of which the classical leads I, II, III, aVL, aVF and V₁–V₃ were calculated from. 66 patients were included in the study. In addition to the conventional ECG (kECG) the novel cECG was registered before reperfusion therapy was started.

Results

In a first round, 19 patients presented with anterior MI, 23 with inferior MI, and 7 either with left bundle branch block or lateral MI. Regarding anterior MI, a significant correlation (P < 0.05) was found between ST elevations in leads I, aVL, V₂ and V₃ comparing cECG and kECG. In inferior MI, there was only a significant correlation (P < 0.05) in lead III between cECG and kECG, but not in II and aVF. Therefore, 17 additional patients were included in the study by placing an additional electrode further away from the sensor array on the chest. ST elevations now correlated in all inferior leads II, III and aVF (P < 0.05) as measured in 9 patients with inferior MI. In addition, in 8 patients an inferior MI was correctly ruled out.

Conclusion

It is possible to identify STEMIs by cECG. This innovative technique could play an important role in the pre-hospital period as well as in the hospital.