Bioimpedance-Based Heart Failure Deterioration Prediction Using a Prototype Fluid Accumulation Vest-Mobile Phone Dyad: An Observational Study

Abstract

BackgroundRecurrent heart failure (HF) events are common in patients discharged after acute decompensated heart failure (ADHF). New patient-centered technologies are needed to aid in detecting HF decompensation. Transthoracic bioimpedance noninvasively measures pulmonary fluid retention.ObjectiveThe objectives of our study were to (1) determine whether transthoracic bioimpedance can be measured daily with a novel, noninvasive, wearable fluid accumulation vest (FAV) and transmitted using a mobile phone and (2) establish whether an automated algorithm analyzing daily thoracic bioimpedance values would predict recurrent HF events.MethodsWe prospectively enrolled patients admitted for ADHF. Participants were trained to use a FAV–mobile phone dyad and asked to transmit bioimpedance measurements for 45 consecutive days. We examined the performance of an algorithm analyzing changes in transthoracic bioimpedance as a predictor of HF events (HF readmission, diuretic uptitration) over a 75-day follow-up.ResultsWe observed 64 HF events (18 HF readmissions and 46 diuretic uptitrations) in the 106 participants (67 years; 63.2%, 67/106, male; 48.1%, 51/106, with prior HF) who completed follow-up. History of HF was the only clinical or laboratory factor related to recurrent HF events (P=.04). Among study participants with sufficient FAV data (n=57), an algorithm analyzing thoracic bioimpedance showed 87% sensitivity (95% CI 82-92), 70% specificity (95% CI 68-72), and 72% accuracy (95% CI 70-74) for identifying recurrent HF events.ConclusionsPatients discharged after ADHF can measure and transmit daily transthoracic bioimpedance using a FAV–mobile phone dyad. Algorithms analyzing thoracic bioimpedance may help identify patients at risk for recurrent HF events after hospital discharge.

Analysis of Consistency of Transthoracic Bioimpedance Measurements Acquired with Dry Carbon Black PDMS Electrodes, Adhesive Electrodes, and Wet Textile Electrodes

“…Before each TBI and ECG test, the subject’s skin at the location of the electrode placement was cleaned with 70% isopropyl alcohol. For this study, we used the fluid accumulation vest (FAV) (Philips, Amsterdam, the Netherlands) [ 6 ] ( Figure 2 and Figure 3 A), which provided TBI measurements at 16 frequencies in the range from 10 kHz to 999 kHz. The volunteers wore the FAV directly on their skin, so that its four electrodes were affixed to their abdominal region.…”

“…Requiring a skilled professional or another person to help to place the electrodes for anatomical consistency increases the cost, reduces usability, and makes the system less suitable for daily home use by heart failure (HF) patients. To overcome this limitation, some studies have proposed using textile electrodes that are embedded into a wearable vest [ 6 , 7 , 8 ]. Wetting the textile electrodes improves the signal fidelity, because their impedance is several orders of magnitude higher than that of the hydrogel Ag/AgCl electrodes [ 9 ].…”

“…A possible solution may lie with a TBI vest, which was reported to offer some promising results [ 6 , 26 ]. However, the main drawback of the TBI vest that was reported was the textile electrodes, which required wetting prior to their use and frequently shifted when a subject moved, which compromised the accuracy of the impedance measurements.…”

Wearable and Flexible Textile Electrodes for Biopotential Signal Monitoring: A review

“…Therefore, they are helpful for offering a robust solution to realize smart clothing for personalized, point of care health monitoring. Textile platforms for wearable and continuous monitoring of ECG have been extensively studied [74,105,106,126,127]. Some of these wearable clothes are waterproof [107], while others were developed to encourage exercising and fitness through the routine monitoring of daily activities [128][129][130].…”

Establishment of a Monitoring Clinic Based on Wearables for Patients with Heart Failure

“…Intrathoracic impedance correlates well with body fluid levels (13). One study showed the use of these devices with a sensitivity of 87% and a specificity of 70% on 106 patients diagnosed with heart failure (14). In a study, to prevent errors in diagnosis, devices were performed to check several parameters such as ECG and intrathoracic impedance and perform accelerometry on 100 patients, which showed 70% specificity and 87% sensitivity in 10 days before onset, which is actually a high sensitivity for that time (15).…”