{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,14]],"date-time":"2025-10-14T00:43:53Z","timestamp":1760402633208,"version":"build-2065373602"},"reference-count":29,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2021,4,12]],"date-time":"2021-04-12T00:00:00Z","timestamp":1618185600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Products &amp; Technology S.L.","award":["DI001-2018"],"award-info":[{"award-number":["DI001-2018"]}]},{"DOI":"10.13039\/501100003030","name":"Ag\u00e8ncia de Gesti\u00f3 d'Ajuts Universitaris i de Recerca","doi-asserted-by":"publisher","award":["DI001-2018"],"award-info":[{"award-number":["DI001-2018"]}],"id":[{"id":"10.13039\/501100003030","id-type":"DOI","asserted-by":"publisher"}]},{"name":"CIBER-BBN","award":["DEKOALE"],"award-info":[{"award-number":["DEKOALE"]}]},{"DOI":"10.13039\/501100004837","name":"Ministerio de Ciencia e Innovaci\u00f3n","doi-asserted-by":"publisher","award":["PID2019-105674RB-I00"],"award-info":[{"award-number":["PID2019-105674RB-I00"]}],"id":[{"id":"10.13039\/501100004837","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000781","name":"European Research Council","doi-asserted-by":"publisher","award":["ERC-StG-638284"],"award-info":[{"award-number":["ERC-StG-638284"]}],"id":[{"id":"10.13039\/501100000781","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100010067","name":"Gobierno de Arag\u00f3n","doi-asserted-by":"publisher","award":["LMP124-18 & T39-20R"],"award-info":[{"award-number":["LMP124-18 & T39-20R"]}],"id":[{"id":"10.13039\/501100010067","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Juan de la Cierva","award":["FJC2018-037369-I"],"award-info":[{"award-number":["FJC2018-037369-I"]}]},{"name":"Marie Sklodowska-Curie","award":["786833"],"award-info":[{"award-number":["786833"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Background: End-stage renal disease patients undergoing hemodialysis (ESRD-HD) therapy are highly susceptible to malignant ventricular arrhythmias caused by undetected potassium concentration ([K+]) variations (\u0394[K+]) out of normal ranges. Therefore, a reliable method for continuous, noninvasive monitoring of [K+] is crucial. The morphology of the T-wave in the electrocardiogram (ECG) reflects \u0394[K+] and two time-warping-based T-wave morphological parameters, dw and its heart-rate corrected version dw,c, have been shown to reliably track \u0394[K+] from the ECG. The aim of this study is to derive polynomial models relating dw and dw,c with \u0394[K+], and to test their ability to reliably sense and quantify \u0394[K+] values. Methods: 48-hour Holter ECGs and [K+] values from six blood samples were collected from 29 ESRD-HD patients. For every patient, dw and dw,c were computed, and linear, quadratic, and cubic fitting models were derived from them. Then, Spearman\u2019s (\u03c1) and Pearson\u2019s (r) correlation coefficients, and the estimation error (ed) between \u0394[K+] and the corresponding model-estimated values (\u0394^[K+]) were calculated. Results and Discussions: Nonlinear models were the most suitable for \u0394[K+] estimation, rendering higher Pearson\u2019s correlation (median 0.77 \u2264r\u2264 0.92) and smaller estimation error (median 0.20 \u2264ed\u2264 0.43) than the linear model (median 0.76 \u2264r\u2264 0.86 and 0.30 \u2264ed\u2264 0.40), even if similar Spearman\u2019s \u03c1 were found across models (median 0.77 \u2264\u03c1\u2264 0.83). Conclusion: Results support the use of nonlinear T-wave-based models as \u0394[K+] sensors in ESRD-HD patients.<\/jats:p>","DOI":"10.3390\/s21082710","type":"journal-article","created":{"date-parts":[[2021,4,12]],"date-time":"2021-04-12T11:05:06Z","timestamp":1618225506000},"page":"2710","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Nonlinear T-Wave Time Warping-Based Sensing Model for Non-Invasive Personalised Blood Potassium Monitoring in Hemodialysis Patients: A Pilot Study"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1455-4923","authenticated-orcid":false,"given":"Flavio","family":"Palmieri","sequence":"first","affiliation":[{"name":"Centre de Recerca en Enginyeria Biom\u00e8dica, Universitat Polit\u00e8cnica de Catalunya, 08028 Barcelona, Spain"},{"name":"CIBER en Bioingenier\u00eda, Biomateriales y Nanomedicina (CIBER-BBN), 50018 Zaragoza, Spain"},{"name":"Laboratorios Rubi\u00f3, Castellbisbal, 08755 Barcelona, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2058-7115","authenticated-orcid":false,"given":"Pedro","family":"Gomis","sequence":"additional","affiliation":[{"name":"Centre de Recerca en Enginyeria Biom\u00e8dica, Universitat Polit\u00e8cnica de Catalunya, 08028 Barcelona, Spain"},{"name":"Escuela Superior de Ingenier\u00eda, Ciencia y Tecnolog\u00eda, Universidad Internacional de Valencia, 46002 Valencia, Spain"}]},{"given":"Jos\u00e9 Esteban","family":"Ruiz","sequence":"additional","affiliation":[{"name":"Nephrology Ward, Hospital Cl\u00ednico Universitario Lozano Blesa, 50009 Zaragoza, Spain"}]},{"given":"Dina","family":"Ferreira","sequence":"additional","affiliation":[{"name":"Laboratorios Rubi\u00f3, Castellbisbal, 08755 Barcelona, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0226-4950","authenticated-orcid":false,"given":"Alba","family":"Mart\u00edn-Yebra","sequence":"additional","affiliation":[{"name":"CIBER en Bioingenier\u00eda, Biomateriales y Nanomedicina (CIBER-BBN), 50018 Zaragoza, Spain"},{"name":"BSICoS Group, I3A, IIS Arag\u00f3n, Universidad de Zaragoza, 50018 Zaragoza, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1960-407X","authenticated-orcid":false,"given":"Esther","family":"Pueyo","sequence":"additional","affiliation":[{"name":"CIBER en Bioingenier\u00eda, Biomateriales y Nanomedicina (CIBER-BBN), 50018 Zaragoza, Spain"},{"name":"BSICoS Group, I3A, IIS Arag\u00f3n, Universidad de Zaragoza, 50018 Zaragoza, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7503-3339","authenticated-orcid":false,"given":"Juan Pablo","family":"Mart\u00ednez","sequence":"additional","affiliation":[{"name":"CIBER en Bioingenier\u00eda, Biomateriales y Nanomedicina (CIBER-BBN), 50018 Zaragoza, Spain"},{"name":"BSICoS Group, I3A, IIS Arag\u00f3n, Universidad de Zaragoza, 50018 Zaragoza, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4130-5866","authenticated-orcid":false,"given":"Julia","family":"Ram\u00edrez","sequence":"additional","affiliation":[{"name":"William Harvey Research Institute, Queen Mary University of London, London E1 4NS, UK"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3434-9254","authenticated-orcid":false,"given":"Pablo","family":"Laguna","sequence":"additional","affiliation":[{"name":"CIBER en Bioingenier\u00eda, Biomateriales y Nanomedicina (CIBER-BBN), 50018 Zaragoza, Spain"},{"name":"BSICoS Group, I3A, IIS Arag\u00f3n, Universidad de Zaragoza, 50018 Zaragoza, Spain"}]}],"member":"1968","published-online":{"date-parts":[[2021,4,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Segall, L., Nistor, I., and Covic, A. 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