(175 days)
The Nimbl system is intended for use by medical professionals and patients who are under medical supervision, for the treatment of the following conditions: - Chronic edema - Lymphedema - Venous insufficiency - Wound healing
The Nimbl system is a pneumatic compression device that delivers intermittent sequential compression treatment to affected extremities for lymphedema, chronic edema, venous insufficiency, and wound healing. This device helps direct and move excess fluid from an impaired lymphatic region to healthy regions, where fluid can be absorbed and processed naturally by the body. The Nimbl controller is used to inflate the connected garment chambers in a pre-programmed sequence from the distal end to the proximal end of the patient. The pressure gradient provides higher distal pressures. This creates a dynamic wave of therapy that directs fluid into the lymphatic capillaries while maintaining distal prevent distal backflow. The patient's healthcare provider determines what pressure setting is appropriate for the patient.
The provided text describes the 510(k) premarket notification for the Nimbl (model PD08-N1) pneumatic compression device. It establishes substantial equivalence to a predicate device (Entre, model PD08-U). The focus of this document is on the comparison of technological characteristics and performance testing to demonstrate similar safety and effectiveness.
Here's an analysis of the acceptance criteria and study data based on the provided text:
Important Note: The provided document is a 510(k) clearance letter and summary, not a detailed clinical study report for an AI/ML medical device. Therefore, many of the requested details regarding AI/ML-specific study design (e.g., number of experts for ground truth, MRMC studies, training set details) are not applicable or not present in this type of submission for a pneumatic compression device. Wearable/Pneumatic Compression devices typically rely on bench testing, electrical safety, software V&V, and usability testing to demonstrate equivalence, rather than large-scale clinical studies with AI components that require expert consensus on image interpretation or similar.
Key Findings from the Document:
The Nimbl device is a pneumatic compression device, not an AI/ML-driven diagnostic or interpretative system. The "Performance Data" section lists types of testing completed, which are typical for hardware devices:
- Electrical safety and electromagnetic compatibility (EMC) testing
- Software verification and validation (including cybersecurity)
- Mechanical bench testing (pressure verification, port strength, component life testing)
- Usability testing
- Environment and distribution testing
The document repeatedly emphasizes that the subject and predicate devices utilize "the same fundamental technology, mode of action, and principles of operation." The "Software-Concern Level" is listed as "Basic Documentation Level" for the Nimbl, although it notes "Moderate Level of Concern" for the predicate with "Minor software updates have been made." This suggests the software functionality is not for complex interpretation or diagnosis.
1. Table of Acceptance Criteria and Reported Device Performance
Given the nature of this device (pneumatic compression) and the document provided, "acceptance criteria" is typically defined by adherence to relevant standards and demonstration of comparable performance to the predicate through bench and usability testing. Specific quantitative "device performance" metrics in the context of diagnostic accuracy (like sensitivity, specificity, AUC) are not relevant or provided here.
| Acceptance Criterion (Implicit for Hardware Device Equivalence) | Reported Device Performance (Summary from Document) |
|---|---|
| Electrical Safety & EMC Compliance | Performed testing following IEC 60601-1 (Medical electrical equipment – General requirements for basic safety and essential performance). (Satisfied) |
| Software Verification & Validation | Performed testing following IEC 62304 (Medical device software - Software life cycle processes), including cybersecurity. Software "Concern Level" is noted as "Basic Documentation Level" (for Nimbl) / "Moderate Level of Concern" (for predicate, with minor updates for Nimbl) indicating low safety risk associated with software. (Satisfied) |
| Mechanical Performance & Durability | Performed mechanical bench testing, specifically mentioning: pressure verification, port strength, and component life testing. The device is designed for a 5-year lifetime, same as the predicate. The pressure range is 19-60 mmHg (subject) vs. 20-80 mmHg (predicate), noted as "Similar; upper limit lowered for patient comfort." The dwelling time and treatment time are the same as the predicate (25 seconds minimum, 1 hour maximum). (Satisfied, with minor difference in pressure range for patient comfort). |
| Usability | Usability testing completed. (Satisfied) |
| Environmental & Distribution Tolerance | Environment and distribution testing completed. (Satisfied) |
| Same Fundamental Technology, Mode of Action, Principles, and Intended Use | The document states: "The Nimbl device and the predicate Entre device are pneumatic compression devices that utilize the same fundamental technology, mode of action, and principles of operation." The "Indications for Use" for both devices are identical: treatment of chronic edema, lymphedema, venous insufficiency, and wound healing, by medical professionals and patients under medical supervision. (Satisfied) |
| Differences Do Not Raise New Safety/Effectiveness Questions | The document explicitly states: "These differences [Bluetooth connectivity, external battery, smaller controller, garment-controller connection updates] do not raise any different questions of safety or effectiveness for the Nimbl system compared to the predicate device." The "Performance Data" section is presented as evidence for this assertion. (Demonstrated through testing and comparative analysis). |
2. Sample Size Used for the Test Set and Data Provenance
As this is a hardware device clearance, rather than an AI/ML diagnostic algorithm, there isn't a "test set" in the context of diagnostic accuracy. The testing performed involves bench testing (e.g., pressure verification, component life testing, port strength), electrical safety/EMC testing, software verification and validation, and usability testing. The sample sizes for these tests would typically be defined by engineering standards (e.g., number of units tested for durability, number of cycles, number of users for usability). These specific details (e.g., 'N' for specific bench tests) are not provided in this summary document, as they would be in the detailed testing reports submitted to the FDA.
Data Provenance: Not applicable in the context of clinical data for an AI/ML algorithm. The data provenance here refers to the origin of the device and testing, which is Tactile Medical. The testing is assumed to be conducted in a controlled lab/test environment. It is not listed as retrospective or prospective clinical data.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
Not Applicable. This device does not generate medical diagnoses or interpretations that require expert human adjudication for "ground truth" establishment in the way AI/ML diagnostic devices do. The "performance" is mechanical and electrical, governed by engineering specifications and standards.
4. Adjudication Method for the Test Set
Not Applicable. See point 3 above.
5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance
Not Applicable. This is 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
Not Applicable. This is a hardware pneumatic compression device. While it has software, it does not perform standalone diagnostic interpretation.
7. The Type of Ground Truth Used
Device Ground Truth: The "ground truth" for this device's performance relies on engineering principles, validated test methods against specifications (e.g., pressure accuracy against a manometer, force against a load cell), compliance with international standards (IEC 60601-1, IEC 62304), and comparability to the predicate device’s established safe and effective performance. Clinical outcomes data for efficacy (treating edema, lymphedema, etc.) are established for the class of devices and the predicate, not newly proven by this 510(k) submission, which focuses on substantial equivalence.
8. The Sample Size for the Training Set
Not Applicable. This device does not have a "training set" in the context of machine learning.
9. How the Ground Truth for the Training Set was Established
Not Applicable. See point 8 above.
§ 870.5800 Compressible limb sleeve.
(a)
Identification. A compressible limb sleeve is a device that is used to prevent pooling of blood in a limb by inflating periodically a sleeve around the limb.(b)
Classification. Class II (performance standards).