This prospective, single-center, single-arm pivotal clinical trial is designed to evaluate the accuracy of blood pressure measurements obtained using the HiCardi M350 patient monitor compared with measurements obtained using an auscultatory sphygmomanometer.

The study will enroll adult volunteers aged 19 years or older, including participants needed to satisfy the blood pressure distribution requirements of ISO 81060-2:2018. The planned enrollment is 100 participants, considering the ISO 81060-2:2018 minimum requirement of 85 participants and an estimated dropout rate of approximately 15%. The study is also designed to obtain at least 255 valid paired blood pressure values.

After written informed consent, participants will undergo screening assessments, including demographics, vital signs, medical and surgical history, prior and concomitant medications, pregnancy testing for women of childbearing potential, bilateral arm circumference measurement, eligibility assessment, and adverse event assessment. On the blood pressure test day, eligibility will be reconfirmed, an enrollment number will be assigned, HiCardi M350 calibration will be performed, and blood pressure measurements will be obtained using both HiCardi M350 and the reference auscultatory method.

The primary effectiveness endpoint is the difference between systolic and diastolic blood pressure values measured by HiCardi M350 and the reference sphygmomanometer under resting conditions. Accuracy will be evaluated according to ISO 81060-2:2018 using Criteria 1 and Criteria 2. Safety will be evaluated based on adverse events, adverse device effects, serious adverse events, serious adverse device effects, unanticipated adverse device effects, and device deficiencies.

Inclusion Criteria:

1. Adults aged 19 years or older.
2. Individuals who visit Severance Hospital and voluntarily provide written informed consent after receiving and understanding sufficient explanation of the study.
3. Individuals with hypertension-range blood pressure may be included to meet the blood pressure distribution requirements. Participants receiving antihypertensive medication may be included only if the type and dose of medication have remained stable for at least 4 weeks before screening. Individuals with dose changes, medication additions, or medication discontinuation within 4 weeks before screening will be excluded.

Exclusion Criteria:

1. Individuals in whom Korotkoff phase V cannot be clearly identified during auscultatory blood pressure measurement.
2. Individuals for whom blood pressure measurement is difficult or expected to be difficult.
3. Individuals with bilateral arm circumference greater than 42 cm.
4. Pregnant women.
5. Individuals currently participating in another clinical trial or who have participated in another clinical trial within 30 days before the screening date.
6. Individuals judged by the investigator to be inappropriate for participation in the clinical trial.