(65 days)
The Microlife Wrist Watch Blood Pressure Monitor, Model BP-3BU1-5 is a device intended to measure the systolic and diastolic blood pressure and pulse rate of an adult individual by using a non-invasive technique in which an inflatable cuff is wrapped around the wrist. This device can be used in connection with the Microlife Thermal Printer, Model PR 1KA1.
The Microlife Wrist Watch Blood Pressure Monitor, Model BP-3BU1-5 is designed to measure the systolic and diastolic blood pressure and pulse rate of an individual by using a non-invasive technique in which as inflatable cuff is wrapped around the wrist. Our method to define systolic and diastolic pressure is similar to the auscultatory method but uses an electronics capacitive pressure sensor rather than a stethoscope and mercury manometer. The sensor converts tiny alterations in cuff pressure to electrical signals, by analyzing those signals to define the systolic and diastolic blood pressure and calculating pulse rate, which is a well-known technique in the market called the "oscillometric method".
The provided document describes the Microlife Wrist Watch Blood Pressure Monitor, Model BP-3BU1-5. However, it does not contain the detailed acceptance criteria or a specific study proving the device meets new acceptance criteria. Instead, it asserts substantial equivalence to a predicate device based on the predicate device's performance and a series of non-clinical tests.
Here's an analysis based on the available information:
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state numerical acceptance criteria for the new device's blood pressure or pulse rate accuracy. It relies on the predicate device's performance.
| Acceptance Criteria (from predicate) | Reported Device Performance (for predicate, assumed for new device due to substantial equivalence) |
|---|---|
| Met relevant requirements of ANSI/AAMI "National Standard for Electronic or Automated Sphygmomanometers" | Met relevant requirements of ANSI/AAMI "National Standard for Electronic or Automated Sphygmomanometers" |
| Met relevant requirements of FDA November 1993 Draft "Reviewer Guidance for Premarket Notification Submissions" (Electrical, Mechanical, Environmental Performance Requirements) | Met relevant requirements for General Functions, Reliability, Drop Test, Operation Condition Test, Storage Test, Vibration Test, Life Test, EMC Test, Pulse Rate Accuracy, Printer Port Function, Altitude Test. No design characteristics violated requirements or resulted in safety hazards. |
| Pulse Rate Accuracy | Pulse Rate Accuracy Test Report performed (results not detailed, but implied to be acceptable) |
2. Sample Size Used for the Test Set and Data Provenance
The document does not provide details on the sample size used for the clinical test set or the data provenance (country of origin, retrospective/prospective). It explicitly states: "Repeat testing was not performed for the modified device, as clinical testing results were not affected by the changes to the modified device." This implies that the clinical data referred to pertains to the predicate device.
3. Number of Experts Used to Establish Ground Truth and Qualifications
The document does not provide any information on the number of experts or their qualifications for establishing ground truth, as new clinical testing was not performed for the modified device. The reference to "ANSI/AAMI 'National Standard for Electronic or Automated Sphygmomanometers'" implies that the ground truth for the predicate device's validation would have followed the methodology outlined in this standard, which typically involves trained observers and mercury sphygmomanometers.
4. Adjudication Method for the Test Set
The document does not provide any information on an adjudication method, as new clinical testing was not performed for the modified device.
5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study was done
No, an MRMC comparative effectiveness study was not done. The device is a standalone blood pressure monitor, not an AI-assisted diagnostic tool for human readers.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was done
The device is inherently a standalone measurement device. Its performance, as validated by the ANSI/AAMI standard for the predicate, would represent its standalone accuracy. The non-clinical tests (e.g., General Functions, Reliability, Pulse Rate Accuracy) assess the algorithm and hardware without human intervention for interpreting results.
7. The Type of Ground Truth Used
For the predicate device's clinical validation (which is being leveraged for substantial equivalence), the ground truth for blood pressure measurements would typically be established using simultaneous auscultation by trained observers with a mercury sphygmomanometer, as per the methodology of the ANSI/AAMI standard. This is considered an expert consensus or reference method.
8. The Sample Size for the Training Set
The document does not specify a separate "training set" sample size. The device uses an "oscillometric method" which is a "well-known technique in the market." This suggests that the underlying algorithms were developed and refined over time based on established physiological principles and data, rather than being a novel machine learning algorithm that requires a dedicated training set as understood in modern AI contexts. The "temperature measurements algorithm and its software codes of the modified devices remains unchanged."
9. How the Ground Truth for the Training Set was Established
As above, the concept of a "training set" as in machine learning is not directly applicable here. The "oscillometric method" relies on analyzing pressure oscillations in the cuff. The fundamental principles and parameters for this method would have been established through extensive research and validation against reference methods (like auscultation) in the development of such devices generally. The document does not describe the specific ground truth establishment for the development of the oscillometric algorithm itself, only the validation of the device against accepted standards.
§ 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).