ChroniSense National Early Warning Score Study (CHESS): a wearable wrist device to measure vital signs in hospitalised patients - a comparison study (Preprint)

Abstract

Wearable devices could be used to continuously monitor vital signs in hospitalised patients but require validation.

This study aims to evaluate the clinical validity of a semi-automated wearable wrist device (ChroniSense Polso™, Yokneam Illit, Israel) to measure vital signs and provide National Early Warning Scores.

Vital signs and National Early Warning Scores measured by the wearable device were compared to standard nurse-lead manual measurements. We enrolled adult patients (aged at least 18 years) who required vital sign measurements for at least every 6 hours in a UK Teaching District General Hospital. Wearable device measurements were not used for the clinical decision-making. The primary outcome was the agreement on the individual National Early Warning parameter scores and vital sign measurements: (1) respiratory rate, (2) oxygen saturation, (3) body temperature, (4) systolic blood pressure and (5) heart rate. Secondary outcomes were the agreement on the total National Early Warning Score, the incidence of adverse events, and user-acceptance. To compare the wearable device measurements with the standard measurements, we analysed vital sign measurements by limits of agreement (Bland-Altman analysis) and undertook kappa agreement analyses for National Early Warning Scores. A user experience survey was conducted with questions on comfort of the wrist device, safety, preference, and use.

We included 132 participants in the study with a mean age of 62 years; the majority were men (102, 77.3%). The highest weighted kappas were found for heart rate (0.69 [0.57 to 0.81] for all 385 measurements) and systolic blood pressure (0.39 [0.30 to 0.47] for all 339 measurements). Weighted kappas were low for respiration rate (0.03 [-0.001 to 0.05] for all 445 measurements), temperature (-0.00 [0.00 to 0.00] for all 231 measurements) and oxygen saturation (-0.11 [-0.20 to -0.02] for all 187 measurements). Weighted kappa using Cicchetti-Allison weights showed a kappa of 0.20 (0.03 to 0.38) when using all 56 total National Early Warning Scores scores. The user acceptance survey found that about half of participants found it comfortable to wear the device and liked the look of it. Most said they would wear the device during a next hospital visit and would recommend it to others.

This study shows promising use of a wearable device to measure vital signs in a hospital setting. Agreement between the standard measurements and wearable were acceptable for systolic blood pressure and heart rate but need to be improved for respiration rate, temperature, and oxygen saturation. Future work needs to improve the clinical validity of wearable devices and larger studies are required that assess clinical outcomes and cost-effectiveness of wearable devices for vital sign measurement.

RR2-http://dx.doi.org/10.1136/bmjopen-2018-028219