In this study, according to the latest released ISO 81060-3:2022 standard requirements, non-invasive blood pressure measurement by cuff at the start and the end time points will be used as oCareTM BP100 start-to-end blood pressure calibration. The invasive arterial catheter (A-line) blood pressure measurement will be used as a reference invasive blood pressure monitor (BPM) equipment. The purpose of the study is to evaluate the stability of the device under evaluation (DUE) and its performance in blood pressure change tracking.

1. The primary goal (Stability Test): to validate the stability of the repeated measurements of DUE, and the corrected standard deviation of each analysis period shall not exceed 6 mmHg.
2. The secondary goal (Blood Pressure Change Tracking): to validate the consistency of DUE vs. the reference BPM equipment in blood pressure change tracking during the change evaluation interval.

Inclusion Criteria:

1. Subject must be over 22 years old on the date of informed consent.
2. Subject who has undergone radial artery cannulation (A-line) (for medical purposes, specifically for arterial pressure monitoring.
3. Subject or his/her legal representative understand the written informed consent and willing to participate as evidenced by signing the informed consent.

Exclusion Criteria:

1. Pregnancy
2. Patients with an intra-aortic balloon pump
3. Patients with arm or finger injuries
4. Patients who have undergone vascular surgery for upper extremities or contraindications for local treatment upon upper extremities
5. Patients with A-line placement in the brachial artery
6. Participants are considered not suitable for inclusion after evaluation by the researchers (such as poor compliant mental status or health conditions, etc.)
7. Participants or his/her legal representative refuse to sign the informed consent form

This study will be conducted in the National Taiwan University Hospital Hsin-Chu Branch. A total of 30~40 patients are intended to be recruited.