Lower body negative pressure (LBNP) is a method derived from space medicine, which in recent years has been increasingly used by clinicians to assess the efficiency of the cardiovascular regulatory mechanisms. LBNP with combined tilt testing is considered as an effective form of training to prevent orthostatic intolerance. We have developed a prototype system comprising a tilt table and LBNP chamber, and tested it in the context of the feasibility of the device for assessing the pilots’ efficiency. The table allows for controlled tilting in the range from −45 to +80° at the maximum change rate of 45°/s. The LBNP value can smoothly be adjusted down to −100 mmHg at up to 20 mmHg/s. 17 subjects took part in the pilot study. A 24-minute scenario included −100 mmHg supine LBNP, head up tilt (HUT) and −60 mmHg LBNP associated with HUT, separated by resting phases. The most noticeable changes were observed in stroke volume (SV). During supine LBNP, HUT and the combined stimulus, a decrease of the SV value by 20%, 40% and below 50%, respectively, were detected. The proposed system can map any pre-programed tilt and LBNP profiles, and the pilot study confirmed the efficiency of performing experimental procedures.
Heart failure (HF) is a major clinical, social, and economic problem. In view of the important role of fluid overload in the pathogenesis of HF exacerbation, early detection of fluid retention is of key importance in preventing emergency admissions for this reason. However, tools for monitoring volume status that could be widely used in the home setting are still missing. The physical properties of human tissues allow for the use of impedance-based noninvasive methods, whose different modifications are studied in patients with HF for the assessment of body hydration. The aim of this paper is to present the current state of knowledge on the possible applications of these methods for remote (home-based) monitoring of patients with HF.
A growing population suffering from or at high risk of
developing cardiovascular
diseases can benefit from rapid, precise, and readily available diagnostics.
Textronics is an interdisciplinary approach for designing and manufacturing
high-performance flexible electronics integrated with textiles for
various applications, with electrocardiography (ECG) being the most
convenient and most frequently used diagnostic technique for textronic
solutions. The key challenges that still exist for textronics include
expedient manufacturing, adaptation to human subjects, sustained operational
stability for Holter-type data acquisition, reproducibility, and compatibility
with existing solutions. The present study demonstrates conveniently
paintable ECG electroconductive coatings on T-shirts woven from polyester
or 70% polyamide and 30% polyester. The up to 600-μm-thick coatings
encompass working electrodes of low resistivity 60 Ω sq–1 sheathed in the insulated pathwaysconjugable
with a wireless, multichannel ECG recorder. Long (800 μm) multiwalled
carbon nanotubes, with scalable reproducibility and purity (18 g per
round of synthesis), constituted the electroactive components and
were embedded into a commercially available screen-printing acrylic
base. The resulting paint had a viscosity of 0.75 Pa·s at 56
s–1 and 25 °C and was conveniently applied
using a paintbrush, making this technique accessible to manufacturers.
The amplified and nondigitally processed ECG signals were recorded
under dry-skin conditions using a certified ECG recorder. The system
enabled the collection of ECG signals from two channels, allowing
the acquisition of cardiac electrical activity on six ECG leads with
quality at par with medical diagnostics. Importantly, the Holter-type
ECG allowed ambulatory recording for >24 h under various activities
(sitting, sleeping, walking, and running) in three male participants.
The ECG signal was stable for >5 cycles of washing, a level of
stability
not reported yet previously. The developed ECG-textronic application
possesses acceptable and reproducible characteristics, making this
technology a suitable candidate for further testing in clinical trials.
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