The goal of this clinical trial is to compare the accuracy, clinical applicability, and usability of different wearable blood pressure monitoring methods integrated in wearable devices, such as smartwatches, in hospitalized patients. The study evaluates novel photoplethysmography (PPG)-based and wrist-oscillometric blood pressure measurement methods against established clinical reference methods (upper-arm cuff measurements on the general ward and invasive arterial blood pressure monitoring (A-line) in the intensive care unit).

The main questions the study aims to answer are:

• Can novel blood pressure monitoring methods suitable for integration into wearable devices achieve clinically acceptable agreement with established reference measurements?
• How does the performance of calibration-dependent wearable devices change over time following calibration?
• How does the performance of the investigated methods compare with each other?
• How do the investigated methods perform for patients with different pre-existing conditions ?

To answer these questions, participants will undergo:

• blood pressure measurements using different wearable devices based on PPG and wrist oscillometry
• standardized reference blood pressure measurements using an upper-arm cuff (general ward) or an existing invasive arterial line (intensive care unit)
• repeated measurements over three consecutive days on the general ward to assess calibration stability and measurement reproducibility,