(125 days)
The Arm Blood Pressure Monitor is intended to measure the systolic and diastolic blood pressure as well as the pulse rate of adult person via non-invasive oscillometric technique in which an inflatable CUFF is wrapped around the upper arm at medical facilities or at home.
The Arm Blood Pressure Monitor is designed as a battery driven automatic non-invasive blood pressure monitor. It can automatically complete the inflation, deflation and measurement, which can measure systolic and diastolic blood pressure as well as the pulse rate of adult person at upper arm within its claimed range and accuracy via the oscillometric technique. The result will be displayed in the international unit mmHg or Kpa.
The device has the data storage function in order for data reviewing, including the systolic pressure, diastolic pressure, pulse rate and measurement time. The device also has low voltage indication, which will be triggered when the battery is low.
The FDA 510(k) clearance letter for the Arm Blood Pressure Monitor does not explicitly state acceptance criteria in a quantitative table or the specific performance metrics achieved in a typical "device performance" section as one might expect for a software-based or diagnostic device. Instead, it refers to compliance with established medical device standards, particularly ISO 81060-2:2018 (and its amendment from 2020) for clinical accuracy.
However, based on the context of the clinical data and the requirements of ISO 81060-2, we can infer the acceptance criteria for accuracy.
Here's a breakdown of the requested information based on the provided document:
Implied Acceptance Criteria and Reported Device Performance
The device's performance is demonstrated by its adherence to the clinical accuracy requirements of ISO 81060-2 Third edition 2018-11 (including AMD1:2020).
Implied Acceptance Criteria of ISO 81060-2:2018 (and AMD1:2020):
The ISO 81060-2 standard consists of two parts for accuracy assessment:
- Criterion 1 (Mean Difference and Standard Deviation):
- The mean difference between the device and the reference measurement for both systolic and diastolic blood pressure shall be $\leq \pm 5$ mmHg.
- The standard deviation of these differences shall be $\leq 8$ mmHg.
- Criterion 2 (Cumulative Percentage of Differences):
- For each subject, the absolute difference between the device and the reference measurement should be calculated.
- The cumulative percentage of devices should have absolute differences within certain thresholds:
- $\leq 5$ mmHg for at least 65% of measurements.
- $\leq 10$ mmHg for at least 85% of measurements.
- $\leq 15$ mmHg for at least 95% of measurements.
Table of Acceptance Criteria and Reported Device Performance (Inferred from ISO 81060-2)
| Acceptance Criterion (from ISO 81060-2) | Systolic Blood Pressure (SYS) | Diastolic Blood Pressure (DIA) | Reported Device Performance (Overall) |
|---|---|---|---|
| Criterion 1 (Mean ± SD) | |||
| Mean difference $\leq \pm 5$ mmHg | $\leq \pm 5$ mmHg | $\leq \pm 5$ mmHg | "not over the limits of ISO 81060-2" |
| Standard deviation $\leq 8$ mmHg | $\leq 8$ mmHg | $\leq 8$ mmHg | "not over the limits of ISO 81060-2" |
| Criterion 2 (Cumulative Differences) | |||
| Differences $\leq 5$ mmHg for $\geq 65$% | $\geq 65$% | $\geq 65$% | "not over the limits of ISO 81060-2" |
| Differences $\leq 10$ mmHg for $\geq 85$% | $\geq 85$% | $\geq 85$% | "not over the limits of ISO 81060-2" |
| Differences $\leq 15$ mmHg for $\geq 95$% | $\geq 95$% | $\geq 95$% | "not over the limits of ISO 81060-2" |
Note: The document explicitly states, "All data's mean error and standard deviation of differences for systolic, diastolic pressure is not over the limits of ISO 81060-2 Third edition 2018-11 [Including AMD1:2020]." This confirms the device met the numerical precision requirements of the standard for mean difference and standard deviation. While it doesn't provide the exact numbers for each group, it confirms compliance with the key statistical thresholds.
Study Details
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Sample Size Used for the Test Set and Data Provenance:
- Total Sample Size: The 28 models were grouped into 7 categories for clinical accuracy testing. Each of these 7 groups had a test set of 100 subjects, except for Group 7, which had 92 subjects.
- Group 1: 100 subjects
- Group 2: 100 subjects
- Group 3: 100 subjects
- Group 4: 100 subjects
- Group 5: 100 subjects
- Group 6: 100 subjects
- Group 7: 92 subjects
- Male/Female Distribution: Each group had a participant distribution of at least 30% male and at least 30% female.
- Age Range: Subjects were "adult person" with an age range of "> 12 years old," specifically noted ranges from 15 to 80 years old across the groups.
- Data Provenance: The document does not explicitly state the country of origin for the clinical data. It also does not explicitly state if the study was retrospective or prospective, but clinical accuracy studies adhering to ISO 81060-2 are typically prospective and involve simultaneous, sequential measurements.
- Total Sample Size: The 28 models were grouped into 7 categories for clinical accuracy testing. Each of these 7 groups had a test set of 100 subjects, except for Group 7, which had 92 subjects.
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Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications of Those Experts:
- The document does not specify the number or qualifications of experts (e.g., radiologists) for establishing ground truth in this context. For blood pressure monitors, "ground truth" is typically established by trained technicians or clinicians using a validated reference method (e.g., mercury sphygmomanometer) following a rigorous protocol (like the auscultatory method per ISO 81060-2). The standard requires independent observers for reference measurements.
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Adjudication Method for the Test Set:
- The document states, "The clinical accuracy test report and data analysis followed the requirements of the ISO 81060-2 Third edition 2018-11 [Including AMD1:2020]. The Same Arm Sequential Method was chosen for all studies."
- ISO 81060-2 outlines a specific method for ground truth establishment for blood pressure. It typically involves multiple independent observers (at least two trained observers) who simultaneously or sequentially measure blood pressure using a validated reference device. Discrepancies between these observers are resolved in accordance with the standard, which usually involves specific rules for averaging or discarding measurements based on predefined variability criteria, rather than a formal "adjudication panel" in the sense of image interpretation.
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If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done:
- No, an MRMC comparative effectiveness study was not done. This type of study is specifically relevant for diagnostic imaging AI devices where human readers interpret medical images with and without AI assistance. For a non-invasive blood pressure monitor, the study focus is on the device's measurement accuracy against a reference standard, not on how it assists human interpretation.
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If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done:
- Yes, in essence, a "standalone" or "algorithm only" performance was evaluated. The device (Arm Blood Pressure Monitor) is an automated system that measures blood pressure. Its clinical accuracy study measures its direct output (systolic and diastolic pressure) against a reference standard. There isn't a "human-in-the-loop" component in the operational measurement process that would affect its core accuracy, as it's an automated device.
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The Type of Ground Truth Used:
- The ground truth was established by comparison with a validated reference measurement method, as prescribed by ISO 81060-2. This typically involves the auscultatory method using a mercury sphygmomanometer or an equivalent validated reference device, with measurements performed by trained observers.
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The Sample Size for the Training Set:
- Not applicable / Not provided. This device is a hardware-based blood pressure monitor that uses an oscillometric technique and a "blood pressure core algorithm." It is not described as a machine learning or AI algorithm that requires a separate "training set" in the conventional sense of deep learning. Its performance is based on its engineering design and the embedded validated algorithm.
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How the Ground Truth for the Training Set Was Established:
- Not applicable / Not provided. As mentioned above, there isn't a "training set" in the common understanding for a typical medical AI device. The core algorithm is likely developed and validated internally by the manufacturer through engineering principles and extensive testing, not necessarily through a separate clinical "training set" with ground truth in the AI context. The clinical data presented is for validation (test set) of the final device, demonstrating its accuracy.
§ 870.1130 Noninvasive blood pressure measurement system.
(a)
Identification. A noninvasive blood pressure measurement system is a device that provides a signal from which systolic, diastolic, mean, or any combination of the three pressures can be derived through the use of tranducers placed on the surface of the body.(b)
Classification. Class II (performance standards).