@article{HelmerHottenrottRodemersetal.2022,
  author    = {Helmer, Philipp and Hottenrott, Sebastian and Rodemers, Philipp and Leppich, Robert and Helwich, Maja and Pryss, R{\"u}diger and Kranke, Peter and Meybohm, Patrick and Winkler, Bernd E. and Sammeth, Michael},
  title     = {Accuracy and Systematic Biases of Heart Rate Measurements by Consumer-Grade Fitness Trackers in Postoperative Patients: Prospective Clinical Trial},
  series = {Journal of Medical Internet Research},
  volume    = {24},
  journal   = {Journal of Medical Internet Research},
  number    = {12},
  doi       = {10.2196/42359},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-299679},
  year      = {2022},
  abstract  = {Background: Over the recent years, technological advances of wrist-worn fitness trackers heralded a new era in the continuous monitoring of vital signs. So far, these devices have primarily been used for sports. Objective: However, for using these technologies in health care, further validations of the measurement accuracy in hospitalized patients are essential but lacking to date. Methods: We conducted a prospective validation study with 201 patients after moderate to major surgery in a controlled setting to benchmark the accuracy of heart rate measurements in 4 consumer-grade fitness trackers (Apple Watch 7, Garmin Fenix 6 Pro, Withings ScanWatch, and Fitbit Sense) against the clinical gold standard (electrocardiography). Results: All devices exhibited high correlation (r≥0.95; P<.001) and concordance (rc≥0.94) coefficients, with a relative error as low as mean absolute percentage error <5\% based on 1630 valid measurements. We identified confounders significantly biasing the measurement accuracy, although not at clinically relevant levels (mean absolute error<5 beats per minute). Conclusions: Consumer-grade fitness trackers appear promising in hospitalized patients for monitoring heart rate.},
  language  = {en}
}
@article{HelmerRodemersHottenrottetal.2023,
  author    = {Helmer, Philipp and Rodemers, Philipp and Hottenrott, Sebastian and Leppich, Robert and Helwich, Maja and Pryss, R{\"u}diger and Kranke, Peter and Meybohm, Patrick and Winkler, Bernd E. and Sammeth, Michael},
  title     = {Evaluating blood oxygen saturation measurements by popular fitness trackers in postoperative patients: a prospective clinical trial},
  series = {iScience},
  volume    = {26},
  journal   = {iScience},
  number    = {11},
  issn      = {2589-0042},
  doi       = {10.1016/j.isci.2023.108155},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-349913},
  year      = {2023},
  abstract  = {Summary Blood oxygen saturation is an important clinical parameter, especially in postoperative hospitalized patients, monitored in clinical practice by arterial blood gas (ABG) and/or pulse oximetry that both are not suitable for a long-term continuous monitoring of patients during the entire hospital stay, or beyond. Technological advances developed recently for consumer-grade fitness trackers could—at least in theory—help to fill in this gap, but benchmarks on the applicability and accuracy of these technologies in hospitalized patients are currently lacking. We therefore conducted at the postanaesthesia care unit under controlled settings a prospective clinical trial with 201 patients, comparing in total >1,000 oxygen blood saturation measurements by fitness trackers of three brands with the ABG gold standard and with pulse oximetry. Our results suggest that, despite of an overall still tolerable measuring accuracy, comparatively high dropout rates severely limit the possibilities of employing fitness trackers, particularly during the immediate postoperative period of hospitalized patients. Highlights •The accuracy of O2 measurements by fitness trackers is tolerable (RMSE ≲4\%) •Correlation with arterial blood gas measurements is fair to moderate (PCC = [0.46; 0.64]) •Dropout rates of fitness trackers during O2 monitoring are high (∼1/3 values missing) •Fitness trackers cannot be recommended for O2 measuring during critical monitoring},
  language  = {en}
}