(266 days)
The Mucosal Impedance Measurement System is indicated for use by medical personnel trained in the usage of enteral feeding tubes for the treatment of adult patients requiring gastric decompression or enteral feeding for the delivery nutrition, fluids, and medications to the patient from an enteral feeding svringe or feedings set designed with ENFit connectors. The measurements of the Mucosal Impedance Measurement System are collected in patients indicated for enteral feeding. This product is single use for no longer than 24 hours.
The Mucosal Impedance Measurement System is equipped with sensors designed to collect and display real time and continuous gastric reactance "XL" measurements. The device is not for use as a sole diagnostic screening tool and is restricted to prescription use in a hospital environment.
The Mucosal Impedance Measurement System senses passive electrical features of the gastric tissue that corelate to of epithelial integrity through a technique known as 'bioimpedance spectroscopy'. Bioimpedance spectroscopy measures the ability of tissue to conduct electricity (resistance) and the ability of tissue to store charged particles (reactance).
The Florence monitor model ISMO 1.0 is an electronic device that delivers electrical current to a small region of the gastric tissue through the Athena Catheter; the device measures the resultant voltage, and then calculates and displays impedance information in numeric and graphic representations. More specifically, to measure the bioimpedance of the gastric mucosa impedance, the device delivers electric current through the Athena Catheter. The resulting voltage developed between the two inner electrodes is sensed, filtered, amplified, and then digitized by the electronic circuits of the monitor. Once the measured voltage from the gastric tissue has been digitized, a proprietary algorithm processes the information and calculates the impedance spectrum and the Central Reactance parameter (XL). The device displays the information as either a function of frequency or as a function of time.
Here's a breakdown of the acceptance criteria and the studies performed for the Mucosal Impedance Measurement System, based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
| Test | Methods / Acceptance Criteria | Reported Device Performance |
|---|---|---|
| Flow rate | "Gravity Flow Rate Testing in Enteral Tubes" as described in the "Catalog of Regulatory Science Tools to Help Assess New Medical Devices" | The Mucosal Impedance Measurement System functioned as intended. |
| Tensile strength | EN1615:2000 Enteral Feeding Catheters And Enteral Giving Sets For Single Use And Their Connectors. Design And Testing (Section 4.1.1) AND EN1618:1997 Catheters other than intravascular catheters - Test methods for common properties (Annex B) | The Mucosal Impedance Measurement System functioned as intended. |
| Liquid leakage | EN1615:2000 Enteral Feeding Catheters And Enteral Giving Sets For Single Use And Their Connectors. Design And Testing (Sections 4.1.3) AND EN1618:1997 Catheters other than intravascular catheters - Test methods for common properties (Annex C) | The Mucosal Impedance Measurement System functioned as intended. |
| Security of connectors | EN1615:2000 Enteral Feeding Catheters And Enteral Giving Sets For Single Use And Their Connectors. Design And Testing (Sections 4.3.1) AND EN1618:1997 Catheters other than intravascular catheters - Test methods for common properties (Annex F) | The Mucosal Impedance Measurement System functioned as intended. |
| Flexibility | ASTM F3505-21 Standard Test Method for Stent and Endovascular Prosthesis Kink Resistance | The Mucosal Impedance Measurement System functioned as intended. |
| EnFit connector (dimensional verification, rigidity, fluid leakage test, stress cracking, resistance to separation from axial load, resistance to unscrewing, resistance to overriding, and disconnection by unscrewing) | ISO 80369-3:2016 Small-bore connectors for liquids and gases in healthcare applications Part 3: Connectors for enteral applications | The Mucosal Impedance Measurement System functioned as intended. |
| Sterilization validation | ISO 11135:2014 Sterilization of health-care products Ethylene oxide - Requirements for the development, validation and routine control of a sterilization process for medical devices | The Mucosal Impedance Measurement System functioned as intended. |
| Packaging validation | ISO 11607-1:2019 Packaging for terminally sterilized medical devices - Part 1: Requirements for materials, sterile barrier systems and packaging systems | The Mucosal Impedance Measurement System functioned as intended. |
| Dimensional verification | Overall length, working length, catheter outer diameter, catheter inner diameter, sensor dimensions, and spacing of the sensors were measured. | The Mucosal Impedance Measurement System functioned as intended. |
| Accuracy - thermal stability | Confirming that the measurements of the central reactance parameter (XL) remain consistent across a temperature range that covers 77-111°F (25-44°C). The PASS criterion was defined as confirming that at least 95% of all measurements are contained within a +/-1Ω tolerance. | Stability of the sensors was confirmed in terms of the dispersion (standard deviation / interquartile range) of a statistically significant number of measurements across the temperature range. The device met the PASS criterion. |
| Accuracy - temporal stability | Confirming that the measurements of the central reactance parameter (XL) remain consistent across 24 hours. The PASS criterion was defined as confirming that at least 95% of all measurements are contained within a +/-1Ω tolerance (which corresponds to the accuracy stated in the Instructions for Use). | Stability of the sensors was confirmed in terms of the dispersion (standard deviation / interquartile range) of a statistically significant number of measurements over the 24-hour period. The device met the PASS criterion. |
| Biocompatibility | Evaluated according to FDA guidance (2023) "Use of International Standard ISO 10993-1," assessing toxicity, irritation, and sensitization. | Results support the biocompatibility of the Athena Catheter. |
| Software | A failure or flaw of the software functions does not present a hazardous situation with a probable risk of death or serious injury. (Basic documentation level identified per FDA Guidance). | The software documentation was found to be at the basic level, implying it met this criterion. |
| Electrical Safety and Electromagnetic Compatibility (EMC) | Basic safety evaluation per the FDA consensus standard IEC-60601-1.2005, AMD1.2012. EMC testing per IEC-60601-1-2.2014. | The test reports addressed basic safety and EMC testing, and passed the applicable clauses. |
| Human factors | Usability validated in an actual clinical environment for intended users and environment, according to "Applying Human Factors and Usability Engineering to Medical Devices" guidance and EN 60601-1-6:2010, AMD1:2013. | All evaluations have been performed according to the specified standards, supporting the safety and effectiveness of the device. |
| Animal Study (Gastric Mucosal Perfusion) | GLP prospective, controlled animal trial with a shock group (MAP ≤ 48 mmHg) compared to a control group, measuring XL and commonly used markers of global perfusion. Target: five continuous impedance measurements per subject/group for 5 hours. | Demonstrated gastric impedance measurements were performed safely and XL measurement was an indirect and consistent marker of gastric mucosal perfusion in the subject animals, showing significant and detectable changes before commonly used markers of global perfusion under hypovolemic shock conditions. There were no adverse events. |
2. Sample Size Used for the Test Set and Data Provenance
- Non-clinical/Bench Studies: The specific sample sizes for each bench test (e.g., flow rate, tensile strength) are not explicitly stated as numerical values in the provided text, but are implied by the use of standards that typically define such sample sizes. The text mentions "a statistically significative number of measurements" for thermal and temporal stability, indicating appropriate methodology.
- Animal Study:
- Control group (CG): N=5
- Shock group (SG): N=16
- Data Provenance: This was a GLP prospective, controlled animal trial. The country of origin of the data is not specified.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
For the non-clinical/bench studies, animal studies, and human factors, the "ground truth" is established by adherence to recognized international and FDA standards/guidances (e.g., ISO, EN, ASTM, FDA guidance documents). There is no mention of specific human experts establishing ground truth for these quantitative technical performance tests in the same way an expert would for an AI diagnostic algorithm.
4. Adjudication Method for the Test Set
Not applicable in the context of these device performance studies, which involve objective measurements against predefined engineering and biological performance criteria, rather than expert-based interpretation.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No. The provided text does not describe an MRMC comparative effectiveness study involving human readers with and without AI assistance. The device is described as measuring and displaying "XL" values, which are direct measurements, not an AI-based interpretation or diagnostic aid for human readers.
6. Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study
Yes, in essence. The internal performance evaluations (e.g., thermal stability, temporal stability, electrical safety, software validation) and the animal study tested the device's ability to accurately collect and process data and function as intended without human interpretation as the primary endpoint. The device's output (XL measurements) is for human interpretation and clinical decision-making, but the studies described focus on the accuracy and stability of the measurement itself rather than a diagnostic output of an AI algorithm. The device is "not for use as a sole diagnostic screening tool."
7. Type of Ground Truth Used
- Bench Studies: Established by defined physical properties, engineering specifications, and compliance with international standards (e.g., ISO, EN, ASTM).
- Biocompatibility: Established by compliance with ISO 10993-1 and FDA guidance, indicating a lack of toxicity, irritation, and sensitization.
- Software: Established by compliance with FDA guidance for software functions, ensuring no hazardous situations.
- Electrical Safety & EMC: Established by compliance with IEC standards.
- Human Factors: Established by compliance with EN 60601-1-6 and FDA guidance, ensuring usability for safety and effectiveness.
- Animal Study: Established by measuring physiological parameters and comparing the device's XL measurements to established markers of global perfusion under induced hypovolemic shock conditions in a controlled, prospective GLP study.
8. Sample Size for the Training Set
The provided text does not mention a training set, as this device's performance evaluation focuses on the accuracy and stability of direct physiological measurements and its engineering compliance, rather than a machine learning model that requires training data. The "proprietary algorithm" processes measured voltage to calculate the impedance spectrum and Central Reactance parameter (XL), but there's no indication it's a machine learning algorithm requiring a separate training phase with labeled data in the context of this submission.
9. How the Ground Truth for the Training Set Was Established
Not applicable, as no training set for a machine learning model is described.
§ 876.1450 Esophageal tissue characterization system.
(a)
Identification. An esophageal tissue characterization system is a device intended for obtaining measurements of electrical properties within esophageal tissue.(b)
Classification. Class II (special controls). The special controls for this device are:(1) All patient contacting components of the device must be demonstrated to be biocompatible.
(2) Performance testing must demonstrate the device can accurately measure the designated electrical characteristics.
(3) Mechanical safety testing must demonstrate that the device will withstand forces encountered during use.
(4) Software verification, validation, and hazard analysis must be performed.
(5) Electromagnetic compatibility and electrical safety, mechanical safety, and thermal safety of the device must be performed.
(6) Performance data must validate the reprocessing instructions for any reusable components of the device.
(7) Labeling must include:
(i) Specific instructions regarding the proper placement and use of the device;
(ii) Instructions for reprocessing of any reusable components; and
(iii) An expiration date for single use components.