Wearable Technology: The Future of Hospitals
Wissensdatenbank Technologie Datenmanagement & Digitalisierung Mensch Patient*innenzentrierung B.1: Wearable-basiertes kontinuierliches PatientInnen-MonitoringThe healthcare industry is undergoing a transformative shift towards more efficient and patient-centric care. One significant development is the integration of the Internet of Things (IoT) in hospitals, paving the way for the concept of "Smart Hospitals." These innovative healthcare facilities leverage IoT to enhance the patient experience, streamline operations, and improve overall healthcare outcomes. Wearables, a key component of IoT, are at the forefront of this transformation, playing a crucial role in monitoring and improving patient care.
What is a Wearable?
Wearable technology refers to electronic devices that can be worn on the body, often designed to collect and analyze data (typically vital signs) about the user’s health. These devices range from fitness trackers and smartwatches to more sophisticated medical-grade devices that monitor vital signs continuously. Unlike spot measurements, which provide a snapshot of a patient's vital signs at a single point in time, wearables offer continuous monitoring, providing a dynamic and comprehensive view of the patient's health. The devices are designed to collect a set of physiological parameters every few mins (device dependent) and the data is then automatically sent to a cloud-based web platform repository.
Using Wearables to Estimate NEWS in Real-Time
Typically early warning scores are captured routinely through spot measurements taken manually at intervals throughout the day. These measurements, while useful, have limitations. They can miss subtle but significant changes in a patient's condition that occur between readings. Through the use of wearables, on the other hand, a new patient risk score can be determined that is based on more frequent measurements of the patient’s physiological parameters and with the additional element of time to the scoring approach. The potential of wearables in this context is clear, with the opportunity for continuous and automatic aggregation of data, enabling the detection of trends that might indicate the early stages patient deterioration. When combined with advanced algorithms, wearable technology can provide insights that help healthcare providers make informed decisions, reduce the risk of adverse events, and improve patient outcomes.
How Do Wearable Sensors Measure Vital Signs?
Photoplethysmography
Photoplethysmography (PPG) is a common method used by wearable devices to measure vital signs. PPG is an optical technique that uses light-emitting diodes (LED) to detect blood volume changes in the microvascular bed of tissue. It works by emitting light into the skin and measuring the amount of light that is either absorbed or reflected by the blood vessels. The amount of light that is absorbed at any given time is dependent on the hemoglobin concentration in the blood which is dependent on the changing volume of blood in the vessels during each cardiac cycle. It used infrared or green light for analysis as the color reflects the differences in wavelengths that penetrate the tissues at different depths. The sensor is commonly placed on highly perfused areas such as fingertips, earlobes or forehead and then connected to a monitor device with an interface that allows data transmission and synchronisation.
PPG Application to Heart Rate Monitoring
The most reliable measurement obtained through PPG is heart rate, as the signal generated by the pulse is strong and consistent. The wearable device captures these variations in light absorption, where as the heart beats, the changing blood volume scatters the amount of light received and the distance travelled by the light through them changes. The peak absorption coefficients correspond to wavelengths around 540nm and 570nm. At these wavelengths the absorption change due to the blood volume change is the greatest, and the photodiode measures the strongest pulsate signal.
PPG Application to Respiratory Rate and Blood Pressure
These are inferred from the slower changes in the heart rate signal and the amplitude changes in the waveform produced. During the inhale cycle, the intra-thoracic pressure changes cause decreased stroke volume of the left ventricle, which leads to a smaller PPG amplitude. Similarly, during expiration, the left ventricle stroke volume increases, which results in increased pulse amplitude. As the technology develops, the reliability of these measurements is expected to improve.
PPG Application to Temperature Monitoring: Currently under development, temperature measurement via wearables is expected to become more reliable with advancements in sensor technology.
Challenges in Wearable Measurements
Wearable devices face several challenges in accurately measuring vital signs, particularly due to noise caused by movement. For instance, when a patient moves, the PPG signal can become distorted, leading to inaccurate readings. Therefore, it is essential to develop algorithms that can filter out noise and focus on data collected when the patient is at rest, much like how spot measurements are traditionally taken in a controlled setting.
Potential of Wearables in the Hospital Setting
Integrating wearables in the hospital is still in the infancy stage, but they still can improve patient outcomes by allowing for more frequent monitoring of the patient’s vital signs. In traditional hospital settings, early warning scores are are obtained from spot measurements and summarized into a single parameter that can be used to risk-stratify the patients and determine specific treatments or predict patient clinical deterioration. Subtle changes in vital signs often precede patient deterioration, potentially leading to severe events like ICU admissions. Early detection is crucial but challenging due to healthcare staff's workload and the complexity of monitoring multiple patients. Furthermore, such manual calculations of EWS are error-prone and time-consuming and healthcare workers still must physically measure the patient’s vital signs at set intervals throughout the day including when the patient is asleep. Integrating wearable technology with AI enhances EWS effectiveness by providing continuous monitoring and close to real-time data analysis. Using AI-based tools we can analyze the collected data, identify trends, and predict potential health issues before they become critical. Manual EWS provide relevant data on patients’ health status, but interval measurements may not capture early deterioration of vital signs, especially at night. Unplanned ICU admissions are associated with increased mortality rates, longer hospital stays, and higher hospitalization costs. Wearable devices can reduce patient discomfort from fewer measurements, allow patient mobility, and reduce nurse workload. Additionally, these devices promise safe patient transport between hospital wards while continuously monitoring for any changes in the patient’s vital signs.
Enhancing the Predictive Nature of Early Warning Scores with Wearables
Early warning score calculations can benefit greatly from wearable digital technologies. Through the B1 project, we conducted a pilot study using a wearable wrist-based device to provide NEWS in a hospital setting. This study demonstrated that wearable devices could provide a convenient and reliable method of patient monitoring. In the next article we will discuss how we can build the infrastructure in the hospital to support succesful implementation of wearables for patient monitoring.
Zitierung des Beitrags
Leifke, M., Geissmann, L. & Wehrli, S. (2025). Wearable Technology: The Future of Hospitals. In Flagshipprojekt SHIFT. Wissensbeitrag B.1 (Nr. 3).