(169 days)
The FlowMet-R is a non-invasive probe that is affixed to the fingers or toes and intended to quantify tissue blood flow rate.
The FlowMet-R™ is a non-invasive probe that is affixed to the fingers or toes and intended to quantify tissue blood flow rate. The FlowMet-R™ is a miniaturized clip-on probe, designed to be affixed to the fingers or toes. The FlowMet-R™'s clamshell housing blocks the laser output when not in use or when applied to a digit.
Here's an analysis of the acceptance criteria and the study that proves the device meets them, based on the provided text:
The document does not explicitly state "acceptance criteria" for performance metrics in a table format. However, it presents performance tests and their outcomes, implying that successful completion of these tests demonstrates the device meets the necessary performance standards for substantial equivalence.
1. Table of Acceptance Criteria and Reported Device Performance
Based on the performance data section, here's a reconstructed table of implied acceptance criteria and reported performance:
| Acceptance Criterion (Implied) | Reported Device Performance |
|---|---|
| Benchtop Testing (Comparison to PeriCam PSI) | |
| Similar response and high linearity (R²) to known flow rates | FlowMet-R™ R² > 0.999, PeriCam PSI R² > 0.95. Both devices demonstrated similar response and high linearity between data output and flow rate for volumetric flow rates from 2-20ml/min. |
| Benchtop Testing (Impact of Skin Coloration) | |
| No significant impact of skin coloration on flow rate measurements | The degree of absorption within a skin tissue analog (simulating skin color) did not significantly affect the flow rate within the sample as determined by the FlowMet-R™. |
| Clinical Testing (Comparison to Laser Doppler Flowmeter) | |
| Measures expected decrease in flow rates during occlusion | FlowMet-R™ system measures the expected decrease in flow rates during occlusion. |
| Measured decrease within +/-22% of Laser Doppler system | Resulting measured decrease is within +/-22% of the laser Doppler system. |
| Significant correlation with Laser Doppler flowmeter | Flow measurements from the FlowMet-R™ and laser Doppler devices were found to be significantly correlated for all patients with significant p values (0.8. |
| Clinical Testing (Impact of Skin Color) | |
| No significant difference in mean flow value among different skin colors | An ANOVA test demonstrated no significant difference in the mean flow value among all grouped skin color/ethnicity groups (White/Caucasian, Hispanic/Latino, Asian, African American). |
| No significant decrease in light source throughput due to skin tone | The difference in mean transmitted intensity between light-skinned (White/Caucasian) patients and any other group demonstrated that skin tone did not significantly decrease light source throughput. |
2. Sample Sizes Used for the Test Set and Data Provenance
- Benchtop Test (FlowMet-R™ vs. PeriCam PSI): No specific sample size in terms of test runs or repeated measurements is provided, but it states "flow rates were varied from 2-20ml/min" and "data was collected concurrently from both systems for a specified length of time (30 seconds) at each flow rate." The data provenance is controlled laboratory conditions using a "tissue analog."
- Benchtop Test (Impact of Skin Coloration): No specific sample size is provided beyond "FlowMet-R™ data was collected under known flow rate conditions using a tissue analog." Skin colors were "simulated by creating silicone-based skin analogs with varying optical absorption." The data provenance is controlled laboratory conditions using "tissue analogs."
- Clinical Test (FlowMet-R™ vs. Laser Doppler):
- Sample Size: 10 patients (5 male, 5 female).
- Data Provenance: Not explicitly stated, but it is a prospective clinical test on human subjects ("Data was collected from 10 patients before, during, and after vascular disruption induced via brachial artery occlusion.").
- Clinical Test (Impact of Skin Color):
- Sample Size: 91 patients (181 total limbs, 84 from females, 97 from males). Grouped by ethnicity/skin color: White/Caucasian (N=144), Hispanic/Latino (N=23), Asian (N=11), and African American (N=3).
- Data Provenance: Not explicitly stated, but implies prospective collection from human subjects ("FlowMet-R™ blood flow and sensor intensity data was collected from 91 patients").
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The document does not describe the use of experts to establish ground truth in the context of adjudication for the test set.
- For the benchtop tests, the "ground truth" was established by known volumetric flow rates or controlled optical properties of tissue analogs.
- For the clinical tests, the "ground truth" was established by:
- The expected physiological response to vascular occlusion.
- Comparison to a legally marketed predicate device (Laser Doppler flowmeter, K974285, specifically PeriFlux System 5000), which itself serves as a clinical reference.
4. Adjudication Method for the Test Set
No adjudication method involving experts is mentioned for any of the described tests. The comparisons are against physical ground truths (known flow rates, simulated skin colors) or against established medical devices (predicate PeriCam PSI, PeriFlux System 5000 Laser Doppler).
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No MRMC comparative effectiveness study involving human readers and AI assistance is reported. This device is a measurement tool, not an AI for image interpretation that would typically involve human-in-the-loop performance studies.
6. Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study
The described performance tests are all standalone (algorithm only) performance studies, as the device directly measures and quantifies tissue blood flow rate. There is no human intervention in the interpretation of the raw data that the device outputs; the output itself is the measurement. The studies compare the device's measurements against known physical parameters or another established device, not against human judgment.
7. The Type of Ground Truth Used
- Benchtop Test (FlowMet-R™ vs. PeriCam PSI): Ground truth was based on a known, controlled volumetric flow rate using a pump system and tissue analog.
- Benchtop Test (Impact of Skin Coloration): Ground truth was based on known, controlled optical absorption (simulating skin color) in tissue analogs.
- Clinical Test (FlowMet-R™ vs. Laser Doppler): Ground truth was established by:
- Physiological changes (expected decrease in flow during occlusion).
- Comparison to measurements from a legally marketed predicate device (Laser Doppler flowmeter), which serves as a clinical reference standard.
- Clinical Test (Impact of Skin Color): Ground truth was based on statistical analysis of measured flow values across self-reported or observed ethnicity/skin color groups, to determine if significant differences existed.
8. The Sample Size for the Training Set
The document describes performance testing (validation) of the device. It does not provide information about a "training set" because this device is not presented as an AI/machine learning device that requires a training set in the conventional sense. The device uses "Laser Speckle Imaging" principles, implying fixed algorithms based on physics rather than learned patterns from data.
9. How the Ground Truth for the Training Set Was Established
As no training set is mentioned or implied for this type of device, this question is not applicable.
§ 870.2100 Cardiovascular blood flowmeter.
(a)
Identification. A cardiovascular blood flowmeter is a device that is connected to a flow transducer that energizes the transducer and processes and displays the blood flow signal.(b)
Classification. Class II (performance standards).