(184 days)
The Somfit system is a non-invasive prescription device for home use with patients suspected to have sleep-related breathing disorders. The Somfit is a diagnostic aid for the detection of sleep-related breathing disorders, sleep staging (REM, N1, N2, N3, Wake), and snoring level. The Somfit system acquires electrical data from three frontal electrodes, triaxial accelerometer data, acoustic and plethysmographic data. The Somfit calculates and reports to clinicians EEG/EOG channels, Sleep Stages, SpO2, Peripheral Arterial Tonometry (PAT) signal, pulse rate, and snoring level. The Somfit calculates and reports to clinicians derived parameters such as PAT-derived Apnea Hypopnea Index, Obstructive Desaturation Index; and hypnogram-derived indices such as time in each sleep stage. Somfit data is not intended to be used as the sole or primary basis for diagnosing any sleep-related breathing disorder, prescribing treatment, or determining whether additional diagnostic assessment is warranted. The Somfit is not intended for use as life support equipment, for example vital signs monitoring in intensive care unit. The Somfit is a prescription device indicated for adult patients aged 21 years and over.
The Somfit is a home-based sleep monitoring device which records signals from the patient's forehead and surrounding environment. Somfit is a wearable, low voltage, battery operated device which is attached to subject forehead via a self-adhesive and disposable skin electrode patch. The electrodes are placed on the anterior Prefrontal cortex (PFC) at the Fp1 and Fp2 positions according to the 10/20 EEG system. The device allows for recording of two frontal EEG signals, pulse rate, SPO2, Peripheral Arterial Tonometry (PAT), PPG, motion, and snore. Somfit uses a mobile phone application to acquire data wirelessly via Bluetooth LE technology, then transfer into a secure cloud, for management, storage and postprocessing. The software reports measured parameters in a format compatible with AASM guidelines, including sleep time, pAHI and conventional graphical displays such as a hypnogram.
The Somfit device underwent rigorous testing to establish its performance against predefined acceptance criteria, particularly for its ability to detect sleep stages and related parameters.
Here's a breakdown of the acceptance criteria and the supporting study:
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly present a formal "acceptance criteria" table with specific thresholds for each metric. However, the clinical performance section implicitly defines acceptance by demonstrating non-inferiority to the predicate device (Watch-PAT300) and superior or comparable performance against the gold standard (PSG) for key metrics.
Based on the provided text, here's a table summarizing the performance metrics that act as implicit acceptance criteria:
Implicit Acceptance Criteria & Reported Device Performance for Somfit
| Metric | Implicit Acceptance Criteria (Comparative) | Reported Somfit Performance | Reported Watch-PAT300 Performance | Ground Truth (PSG) |
|---|---|---|---|---|
| PAT-derived AHI (pAHI) | Non-inferiority to predicate (Watch-PAT300) compared to PSG. | Mean difference with Watch-PAT300: 0.294 (95% CI: -2.661, 2.074). Mean difference with PSG: 0.658 (CI: -1.012, 2.326). | Mean difference with PSG: 2.499 (CI: 0.732, 4.265). | Polysomnography (PSG) |
| Obstructive Desaturation Index (ODI) | Superior or comparable accuracy to predicate. | Mean difference with PSG: 0.658 (CI: -1.012, 2.326). | Mean difference with PSG: 2.499 (CI: 0.732, 4.265). | Polysomnography (PSG) |
| N1/N2 Merged Sleep Stages Agreement | High agreement with PSG; superior to predicate. | 80.92% agreement (95% CI: 79.96, 81.89) | 61.77% agreement (95% CI: 60.99, 62.55) | Polysomnography (PSG) (consensus of three scoring sleep technologists) |
| NREM/REM/Wake Stage Differential Agreement | High agreement with PSG; superior to predicate. | 86.79% agreement (95% CI: 85.76, 87.81) | 74.42% agreement (95% CI: 73.51, 75.32) | Polysomnography (PSG) (consensus of three scoring sleep technologists) |
| Sleep/Wake Determination Agreement | High agreement with PSG; superior to predicate. | 89.45% agreement (95% CI: 88.53, 90.38) | 82.09% agreement (95% CI: 81.37, 82.82) | Polysomnography (PSG) (consensus of three scoring sleep technologists) |
| SpO2 Accuracy (ARMS) | Maintain or outperform predicate, satisfy ISO 80601-2-61. | 1.46% | 1.88% (Watch-PAT300) | Gold standard SaO2 (invasive controlled desaturation study) |
| Pulse Rate Accuracy | Satisfy ISO 80601-2-61. | 1.91 BPM (vs Masimo), 1.81 BPM (vs Nellcor) | Not explicitly compared here | Masimo and Nellcor reference oximeters |
2. Sample Size and Data Provenance
- Test Set Sample Size: 92 subjects for the comparative clinical study involving Somfit, Watch-PAT300, and PSG.
- Data Provenance: The subjects were recruited from 3 site locations in Australia. The study was a prospective clinical study conducted to compare the devices' performance.
3. Number of Experts and Qualifications for Ground Truth
- Number of Experts: Three scoring sleep technologists.
- Qualifications of Experts: The document states they were "scoring sleep technologists." Specific educational background or years of experience are not provided, but their role implies expertise in polysomnography scoring.
4. Adjudication Method for the Test Set
The adjudication method for sleep staging ground truth was expert consensus. The PSG epochs were classified based on the "consensus of three scoring sleep technologists." This implies a form of 3-way consensus. Further details on how discrepancies were resolved (e.g., majority rule, discussion to reach agreement) are not provided.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No, a traditional MRMC comparative effectiveness study was not explicitly described in the provided text in the context of human readers improving with AI vs. without AI assistance. The study evaluated the device's performance (Somfit and Watch-PAT300) against a human-scored gold standard (PSG), rather than measuring the improvement of human readers assisted by AI. The Somfit system is described as a diagnostic aid that calculates and reports parameters to clinicians, implying that clinicians review the output, but the study design was not focused on measuring changes in human reader performance.
6. Standalone (Algorithm Only) Performance
Yes, the study primarily evaluated the standalone performance of the Somfit algorithm (and Watch-PAT300) in deriving parameters like pAHI and sleep stages, comparing its output directly to the gold standard PSG and the predicate device. There was no human-in-the-loop component as part of the evaluated performance for regulatory submission.
7. Type of Ground Truth Used
The primary ground truth used for the clinical study was Polysomnography (PSG), which is considered the gold standard technology for diagnosing sleep disorders. Specifically, for sleep staging, it was expert consensus-scored PSG data. For SpO2, it was gold standard SaO2 data obtained from an invasively controlled desaturation study.
8. Sample Size for the Training Set
The document does not provide information on the sample size for the training set for the Somfit algorithms. It focuses solely on the clinical validation/test set.
9. How the Ground Truth for the Training Set Was Established
As the training set details are not provided, the method for establishing its ground truth is also not mentioned in the document.
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November 30, 2023
Image /page/0/Picture/1 description: The image shows the logo of the U.S. Food and Drug Administration (FDA). On the left is the Department of Health & Human Services logo. To the right of that is the FDA logo, which consists of the letters "FDA" in a blue square. To the right of the square is the text "U.S. FOOD & DRUG ADMINISTRATION" in blue.
Compumedics Limited Michael Frischman Electronics Engineer 30-40 Flockhart St Abbotsford, Victoria 3067 Australia
Re: K231546
Trade/Device Name: Somfit Regulation Number: 21 CFR 868.2375 Regulation Name: Breathing Frequency Monitor Regulatory Class: Class II Product Code: MNR, OMC Dated: October 30, 2023 Received: October 30, 2023
Dear Michael Frischman:
We have reviewed your section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (the Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database available at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.
Additional information about changes that may require a new premarket notification are provided in the FDA guidance documents entitled "Deciding When to Submit a 510(k) for a Change to an Existing Device" (https://www.fda.gov/media/99812/download) and "Deciding When to Submit a 510(k) for a Software Change to an Existing Device" (https://www.fda.gov/media/99785/download).
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Your device is also subject to, among other requirements, the Quality System (QS) regulation (21 CFR Part 820), which includes, but is not limited to, 21 CFR 820.30, Design controls; 21 CFR 820.90, Nonconforming product; and 21 CFR 820.100, Corrective and preventive action. Please note that regardless of whether a change requires premarket review. the OS regulation requires device manufacturers to review and approve changes to device design and production (21 CFR 820.30 and 21 CFR 820.70) and document changes and approvals in the device master record (21 CFR 820.181).
Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); medical device reporting of medical device-related adverse events) (21 CFR Part 803) for devices or postmarketing safety reporting (21 CFR Part 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reportingcombination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR Part 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR Parts 1000-1050.
Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-device-safety/medical-device-reportingmdr-how-report-medical-device-problems.
For comprehensive regulatory information about medical devices and radiation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medicaldevices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-device-advice-comprehensive-regulatoryassistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).
Sincerely,
Patrick Antkowiak -S
for Jay Gupta Assistant Director DHT5A: Division of Neurosurgical, Neurointerventional and Neurodiagnostic Devices
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OHT5: Office of Neurological and Physical Medicine Devices Office of Product Evaluation and Quality Center for Devices and Radiological Health
Enclosure
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Indications for Use
510(k) Number (if known) K231546
Device Name Somfit
Indications for Use (Describe)
The Somfit system is a non-invasive prescription device for home use with patients suspected to have sleep-related breathing disorders. The Somfit is a diagnostic aid for the detection of sleep-related breathing disorders, sleep staging (REM, N1, N2, N3, Wake), and snoring level. The Somfit system acquires electrical data from three frontal electrodes, triaxial accelerometer data, acoustic and plethysmographic data. The Somfit calculates and reports to clinicians EEG/EOG channels, Sleep Stages, SpO2, Peripheral Arterial Tonometry (PAT) signal, pulse rate, and snoring level. The Somfit calculates and reports to clinicians derived parameters such as PAT-derived Apnea Hypopnea Index, Obstructive Desaturation Index; and hypnogram-derived indices such as time in each sleep stage. Somfit data is not intended to be used as the sole or primary basis for diagnosing any sleep-related breathing disorder, prescribing treatment, or determining whether additional diagnostic assessment is warranted. The Somfit is not intended for use as life support equipment, for example vital signs monitoring in intensive care unit. The Somfit is a prescription device indicated for adult patients aged 21 years and over.
| Type of Use (Select one or both, as applicable) | |
|---|---|
| Prescription Use (Part 21 CFR 801 Subpart D) | Over-The-Counter Use (21 CFR 801 Subpart C) |
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510(k) Summary
Device Name: Somfit
The following 510(k) summary is being submitted in accordance with 21 CFR 807.92.
Submission Details
Applicant Information:
| Submitter: | Compumedics Limited |
|---|---|
| Address: | 30-40 Flockhart Street, Abbotsford 3067, Victoria, Australia |
| Phone number: | +61 (0) 3 8420 7300 |
| Fax number: | +61 (0) 3 8420 7399 |
| Contact person: | Michael Frischman |
| Address: | 30-40 Flockhart Street, Abbotsford 3067, Victoria, Australia |
| Phone number: | +61 (0) 3 8420 7362 |
| Fax number: | + 61 (0) 3 8420 7399 |
| Email: | michael.frischman@compumedics.com.au |
Submission Prepared: 30th May 2023
Subject Device Information:
| Trade name: | Somfit |
|---|---|
| Common name: | Somfit |
| Product code: | MNR, OMC |
| Classification Names: | Ventilatory Effort Recorder |
| Panel: | Anesthesiology |
| Device class: | II |
| Regulation number: | 21 CFR 868.2375 |
Predicate Device Information
| Trade Name: | Watch-PAT300 |
|---|---|
| Manufacturer: | Itamar Medical, Ltd. |
| 510(k) number: | K180775 |
| 510(k) Decision Date: | 17th August 2018 |
| Classification: | Ventilatory Effort Recorder |
| Product code: | MNR |
| Device class: | II |
| Regulation number: | 21 CFR 868.2375 |
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Reference Device(s) Information
| Trade Name: | NightOwl |
|---|---|
| Manufacturer: | Ectosense |
| 510(k) number: | K191031 |
| 510(k) Decision Date: | 6th March 2020 |
| Classification: | Ventilatory Effort Recorder |
| Product code: | MNR |
| Device class: | II |
| Regulation numbers: | 21 CFR 868.2375 |
| Trade Name: | X4 System |
| Manufacturer: | Advanced Brain Monitoring |
| 510(k) number: | K130013 |
| 510(k) Decision Date: | 31st January 2013 |
| Classification: | Reduced-Montage Standard Electroencephalograph |
| Product code: | OMC |
| Device class: | II |
| Regulation numbers: | 21 CFR 882.1400 |
| Trade Name: | SomnaPatch |
| Manufacturer: | Respironics Inc |
| 510(k) number: | K183625 |
| 510(k) Decision Date: | 18th October 2019 |
| Classification: | Ventilatory Effort Recorder |
| Product code: | MNR |
| Device class: | II |
| Regulation numbers: | 21 CFR 868.2375 |
Device Description
The Somfit is a home-based sleep monitoring device which records signals from the patient's forehead and surrounding environment. Somfit is a wearable, low voltage, battery operated device which is attached to subject forehead via a self-adhesive and disposable skin electrode patch. The electrodes are placed on the anterior Prefrontal cortex (PFC) at the Fp1 and Fp2 positions according to the 10/20 EEG system. The device allows for recording of two frontal EEG signals, pulse rate, SPO2, Peripheral Arterial Tonometry (PAT), PPG, motion, and snore. Somfit uses a mobile phone application to acquire data wirelessly via Bluetooth LE technology, then transfer into a secure cloud, for management, storage and postprocessing. The software reports measured parameters in a format compatible with AASM guidelines, including sleep time, pAHI and conventional graphical displays such as a hypnogram.
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Image /page/6/Picture/0 description: The image shows the logo for Compumedics, a medical device company. The logo features a stylized letter "C" with a smaller letter "m" inside it, followed by the company name "COMPUMEDICS" in a bold, sans-serif font. Below the company name is the tagline "Defining Life's Signals" in a smaller, italicized font. The logo is simple, clean, and professional, and it effectively communicates the company's focus on medical technology and life sciences.
Intended Use / Indications For Use
The Somfit system is a non-invasive prescription device for home use with patients suspected to have sleep-related breathing disorders. The Somfit is a diagnostic aid for the detection of sleep-related breathing disorders, sleep staging (REM, N1, N2, N3, Wake), and snoring level. The Somfit system acquires electrical data from three frontal electrodes, tri-axial accelerometer data, acoustic and plethysmographic data. The Somfit calculates and reports to clinicians EEG/EOG channels, Sleep Stages, Sp02, Peripheral Arterial Tonometry (PAT) signal, pulse rate, and snoring level. The Somfit calculates and reports to clinicians derived parameters such as PAT-derived Apnea Hypopnea Index, Obstructive Desaturation Index; and hypnogram-derived indices such as time in each sleep stage. Somfit data is not intended to be used as the sole or primary basis for diagnosing any sleep-related breathing disorder, prescribing treatment, or determining whether additional diagnostic assessment is warranted. The Somfit is not intended for use as life support equipment, for example vital signs monitoring in intensive care unit. The Somfit is a prescription device indicated for adult patients aged 21 years and over.
Comparison of Intended Use
The Somfit has the same intended use as the Watch-PAT300 as a Home Sleep Apnea Test device. The Somfit is intended only for adults, which narrows the indications for use. Somfit does not make clinical claims of distinguishing obstructive and central apnea, which conventionally is performed through direct measurement of airflow (such as nasal cannula) and respiratory effort (such as abdominal inductive belt),
Comparison of Technological Characteristics
The Somfit uses the same fundamental technology and principles of operation as the Watch-PAT300. Both devices are low power battery-operated ventilatory effort recorders utilizing oximeters, tri-axial accelerometers, microphone, and PAT-based technology. The Somfit is notably worn on forehead as opposed to the wrist, and uses an EEG sensor to directly measure brain activity and determine sleep stage. The Somfit data is acquired using a mobile application which uploads data to the Nexus360 Web Server for automatic and review by physician. This workflow is slightly different to the Watch-PAT300 which uses a push button interface, and stores study data in flash memory until a USB connection to a PC running zzzPAT software is made, and upload to the CloudPAT server is manually initiated. Further analysis of technological characteristics is available in the Substantial Equivalence discussion. The Somfit uses the same underlying principles of operation as the Watch-PAT300, and design differences do not raise questions of safety or effectiveness.
Reference has been made to the X4 System in regards to the use of EEG as opposed to actigraphy for sleep staging. Reference has been made to the SomnaPatch for its use of reflectance oximetry at the forehead location. Reference has additionally been made to the NightOwl in regards to test methods used for the validation of PAT and PAT-derived AHI.
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Use of Reference Devices
In addition to the predicate Watch-PAT300, reference has been made to similar sleep assessment devices to assist in the determination of substantial equivalence, in accordance with FDA Guidance Documentation.
The use of a forehead-based reflectance oximeter by Somfit in comparison to a finger transmittance oximeter was noted as a technological difference by the FDA. The SomnaPatch (K183625) was leveraged as a reference device as it also uses forehead reflectance oximeter technology like Somfit. A tabular comparison and further technical discussion was provided to the FDA. Reference was additionally made to the SomnaPatch regarding the use of a functional simulator for verification and validation of the associated pulse rate channel.
The use of EEG technology for the determination of sleep stage as opposed to actigraphy used by Watch-PAT300 has been noted as a technological difference by the FDA. We believe that this does not raise questions of safety and effectiveness since direct measurement of brain activity through EEG is considered by the American Academy of Sleep Medicine to be preferable to actigraphy, and have provided discussion to that effect in document. However, regardless we leveraged the X4 System (K130013) as a reference device. The X4 System is one of several marketed devices which similarly records EEG/EOG at frontal locations for review by physicians with automatic analysis software (separately cleared as Sleep Profiler). This is fundamentally the same technology utilized by Somfit. Further technical discussion and comparison of devices was provided to the FDA.
The peripheral arterial tonometry (PAT) signal is derived directly from the PPG, where changes in morphology such as relative reduction in amplitude are indicative of sympathetic activity in response to respiratory events. There is no standardized methodology for calculation of PAT, and numerical values of the PAT signal are expected to differ based on electronic characteristics of the acquisition hardware, and other described factors. The primary methodology used by Somfit to validate the PAT channel is comparison of the PAT-derived apnea hypopnea index with that of the predicate device, and gold standard AHI as measured by Polysomnography. Reference was made to the NightOwl device (K191031) which reported the same methods for validation of their PAT channel. Further discussion of test methodology and comparison of devices was provided to the FDA.
Non-Clinical Performance Data
Testing activities were conducted as part of this submission to verify that the Somfit does not raise any issues of safety and effectiveness, and to verify implementation of risk controls. These included:
- Electrical Safety Testing as per IEC 60601-1:2005 (Third Edition) + COR1:2006 + COR2:2007 + ● A1:2012
- Electromagnetic Compatibility Testing as per IEC 60601-1-2:2014, EN 60601-1-2:2015, and ● modification by the listed particular and collateral standards
- Home Healthcare Environmental testing as per IEC 60601-1-11:2015
- Electroencephalograph safety and performance testing as per IEC 60601-2-26:2012
- Pulse oximeter safety and performance testing as per ISO 80601-2-61:2011 including tests with ● functional simulator
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- Hardware bench testing to verify electrical parameters and design specifications
- Software testing to verify functional requirements and system integration ●
Further test details are available in this submission. All tests passed, demonstrated substantial equivalence, and did not raise additional concerns of safety and effectiveness. The test methods are in line with international standards where they exist, and other FDA-cleared devices where outputs have not vet been standardized.
Clinical Performance
Multiple clinical studies were conducted to provide clinical validation of Somfit performance. Detailed results and analysis are available in the substantial equivalence discussion, and clinical volume.
A formal controlled desaturation study was conducted in accordance with ISO 80601-2-61 at Hypoxia Lab. This involved comparison between Somfit Sp0, data and gold standard Sa0, data over an invasively controlled Sall, range of 70%-100%. The Somfit root mean square error (Appe) was 1.46%, out-performing Nonin and Masimo reference devices used during the study, which reported 2.15% and 1.94% respectively. The Watch-PAT300 user guide reports an ARMS of 1.88% based on results from its own controlled desaturation study. The Somfit's ARMS of 1.46% for the same is less, supporting the claim of substantial equivalence, and satisfying performance requirements of ISO 80601-2-61.
Pulse rate data was obtained from Nonin and Masimo reference oximeters during a controlled desaturation study. Two hundred and thirty-seven pulse rate samples were obtained from 12 healthy patients, and analysed using the statistical methods mandated by ISO 80601-2-61. The root-mean square error was found to be 1.91 BPM with a mean difference of 0.017 BPM between the Somfit and Masimo oximeters. The rootmean square error was found to be 1.81 BPM with a mean difference of 0.00 BPM between the Somfit and Nellcor oximeters. Potential sources of error may include inadequate synchronization between devices, since oximeters provide a range of data update rates, and were placed at differing anatomical locations, as well as additional patient motion associated with the condition of profound hypoxemia during wake. In addition to testing against a pulse rate simulator, this clinical performance data supports the claim of substantial equivalence and satisfies validation requirements of ISO 80601-2-61.
A clinical study was conducted to obtain clinical data for the purpose of comparing Somfit and Watch-PAT300. A study protocol was reviewed and approved by an Independent Ethics Committee with predefined hypotheses, study population, endpoints, and analysis techniques. In total 92 subjects were recorded across 3 site locations in Australia. All subjects had Somfit and Watch-PAT300 recording overnight data while undergoing attended polysomnography using the Grael device, which is the gold standard technology to assist in the diagnosis of sleep disorders. Watch-PAT300 and Somfit measured parameters such as PAT-derived AHI (pAHI) and sleep stage concordance were evaluated, and directly compared to each other, and the established ground truth.
Somfit and Watch-PAT300 PAT-derived AHI had a mean difference of 0.294 with 95 percent confidence interval of -2.661, 2.074, which was within the predetermined margin supporting the non-inferiority hypothesis. The mean difference of Somfit and PSG ODI of 0.658 with confidence interval of -1.012, 2.326 was less than the mean difference of Watch-PAT300 and PSG ODI of 2.499 with confidence interval of 0.732,
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4.265, indicating Somfit achieved higher accuracy with respect to the gold standard. Somfit had an 80.92% agreement (95 percent Cl: 79.96, 81.89) for N1/N2 merged sleep stages compared to Watch-PAT300 61.77% ( 95 percent CI: 60.99, 62.55). Somfit had a 86.79% agreement (95 percent CI: 85.76, 87.81) for NREM/REM/Wake stage differential compared to Watch-PAT300 of 74.42% agreement (95 percent Cl: 73.51, 75.32). Somfit had an 89.45% agreement (95 percent CI: 88.53, 90.38) with PSG for sleep/wake determination compared to Watch-PAT300 of 82.09% (95 percent CI: 81.37, 82.82).
The sleep staging confusion matrix for agreement between Somfit and PSG is presented in table 1. The PSG epochs were classified based on the consensus of three scoring sleep technologists.
| Somfit | ||||||
|---|---|---|---|---|---|---|
| PSG | Wake | N1 | N2 | N3 | REM | |
| Wake | 16773 | 981 | 1579 | 142 | 1480 | |
| N1 | 2123 | 1335 | 2502 | 27 | 799 | |
| N2 | 2007 | 1337 | 29089 | 836 | 782 | |
| N3 | 166 | 34 | 4206 | 8224 | 11 | |
| REM | 700 | 89 | 611 | 17 | 11157 |
Table 1: Confusion Matrix between the Somfit and PSG sleep staging
The calculated sensitivities of sleep stages and combinations of sleep stages are presented in table 2, including the number of epochs used for each calculation.
| Stage detectionSensitivities | Somfit(No. PSG epochs) | WatchPAT(No. PSG epochs) |
|---|---|---|
| Pr(Wake PSG Wake) | 0.8004, (20955) | 0.3497, (20909) |
| Pr(N1 PSG N1) | 0.1967, (6789) | N/A, (6770) |
| Pr(N2 PSG N2) | 0.8540, (34051) | N/A, (34006) |
| Pr(N3 PSG N3) | 0.6509,(12641) | 0.4799, (12641) |
| Pr(REM PSG REM) | 0.8873, (12574) | 0.7219, (12555) |
| Pr(N1+N2 PSG N1+N2) | 0.8388,(40840) | 0.7662, (40776) |
| Pr(NREM PSG NREM) | 0.8897, (53481) | 0.9042, (53417) |
| Pr(Sleep PSG Sleep) | 0.9244, (66055) | 0.9706, (65972) |
Table 2. Sensitivities for different sleep stages and combinations of sleep stages.
The estimates of differences in the percent agreement between Watch-PAT300 and PSG consensus versus the percent agreement between Somfit and PSG consensus for the three sets of sleep staging categories are presented in table 3.
| Point estimate, | 95% | 97.5% | |
|---|---|---|---|
| % | Confidence Interval | Confidence Interval | |
| N1, N2 merged | -19.23 | [-22.57; -15.89] | [-23.07; -15.39] |
| NREM/REM/Wake | -12.49 | [-15.97; -8.99] | [-16.49; -8.49] |
| Sleep/Wake | -7.45 | [-10.89; -4.03] | [-11.37; -3.53] |
Table 3: Estimates of the difference in sleep staging percent between Somfit and PSG consensus, and between Watch-PAT and PSG consensus using non-parametric bootstrap sampling.
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Image /page/10/Picture/0 description: The image shows the logo for Compumedics. The logo consists of a blue circle with a stylized "m" inside, followed by the word "COMPUMEDICS" in blue, and the tagline "Defining Life's Signals" in a smaller font below. The logo is simple and professional, and the blue color gives it a sense of trust and reliability.
A detailed comparison is provided through evaluation of design features such as energy source, principles of operation, materials, and user interface. Further comparison and analysis is available in VOL_012_Substantial Equivalence Discussion.
| Predicate Device Watch-PAT300(K180775) | New DeviceSomfit | |
|---|---|---|
| Manufacturer | Itamar Medical Ltd | Compumedics Limited |
| Device Classification | MNR | MNR, OMC |
| FDA Classification | Class II | Class II |
| Indications for Use | The Watch-PAT300 (WP300) device is a non-invasivehome care device for use with patients suspected tohave sleep related breathing disorders. The WP300 isa diagnostic aid for the detection of sleep relatedbreathing disorders, sleep staging (Rapid EyeMovement (REM) Sleep, Light Sleep, Deep Sleep andWake), snoring level and body position. The WP300generates a peripheral arterial tonometry ("PAT")Respiratory Disturbance Index ("PRDI"), Apnea-Hypopnea index ("PAHI"), Central Apnea-Hypopneaindex ("PAHIc"), PAT sleep staging identification(PSTAGES) and optional snoring level and bodyposition discrete states from an external integratedsnoring and body position sensor. The WP300'sPSTAGES and snoring level and body position providesupplemental information to its PRDI/PAHI/PAHIc.The WP300's PSTAGES and snoring level and bodyposition are not intended to be used as the sole orprimary basis for diagnosing any sleep relatedbreathing disorder, prescribing treatment, ordetermining whether additional diagnostic assessmentis warranted. PAHIc is indicated for use in patients 17years and older. All other parameters are indicated for12 years and older | The Somfit system is a non-invasive prescription device forhome use with patients suspected to have sleep-relatedbreathing disorders. The Somfit is a diagnostic aid for thedetection of sleep-related breathing disorders, sleep staging(REM, N1, N2, N3, Wake), and snoring level. The Somfit systemacquires electrical data from three frontal electrodes, tri-axialaccelerometer data, acoustical and plethysmographic data.The Somfit calculates and reports to clinicians EEG/EOGchannels, Sleep Stages, SpO2, Peripheral Arterial Tonometry(PAT) signal, pulse rate, and snoring level. The Somfitcalculates and reports to clinicians derived parameters such asPAT-derived Apnea Hypopnea Index, Obstructive DesaturationIndex; and hypnogram-derived indices such as time in eachsleep stage. Somfit data is not intended to be used as the soleor primary basis for diagnosing any sleep-related breathingdisorder, prescribing treatment, or determining whetheradditional diagnostic assessment is warranted. The Somfit isnot intended for use as life support equipment, for examplevital signs monitoring in intensive care unit. The Somfit is aprescription device indicated for adult patients aged 21 yearsand over. |
| Type of Use | Prescription Use Only | Prescription Use Only |
| Patient population | 12 years and above, with some features 17 years andabove | Adults – 21 years and above |
| Usage Environment | Home | Home |
| Mass | 98g (excluding uPAT probe weight of 20g) | ≤ 15g (with battery) |
| Dimensions | 69mm x 59mm x 17mm | 43mm x 43 mm x 19.7 mm(device + charging cradle) |
| Biocompatibility | Overnight use on intact skin | Overnight use on intact skin |
| Materials | Plastic Bracelet (unspecified) | Adhesive (wet) electrodeABS Plastic |
| Sold Sterile orSterilization Required | No | No |
| Energy Source | One OTS 1.5V Alkaline AAA battery OR onerechargeable AAA 1.2V Nickel-metal hydride (NiMH)rechargeable battery> 700mAh | 1 x 120mAh 3.7V Li-Ion battery |
| Battery Life | Approximately 10 hours | Hours of Use:On standby/idle mode: 48 hours (2 days) |
| Recording: 16 hours continuous recording | ||
| Microprocessor | ARM (Nordic) | ARM (TI) |
| Electronic Sensors | Photodiode | Photodiode |
| Oximeter front end (AFE4404) | Oximeter front end (AFE4404) | |
| Microphone | Microphone | |
| Accelerometer | Accelerometer | |
| EEG Amplification | ||
| Channel | PAT | PAT |
| Pulse Rate | Pulse Rate | |
| Oximetry | Oximetry | |
| Actigraphy | EEG | |
| Snoring (Optional) | Snoring | |
| Body Position (Optional) | Motion | |
| Chest Movement (Optional) | ||
| Analysis Output | pRDI | pAHI |
| pAHI | Sleep stages | |
| pAHIc | Snoring Level | |
| ODI | ODI | |
| Sleep stages | ||
| Snoring level (optional) | ||
| Body Position discrete states (Optional) | ||
| Application Site | Main device on wrist with finger probe. | Forehead |
| Device Visual Indicator | OLED screen | Green and blue LEDs on device, mobile application |
| User Control | Device push buttons | Start/stop button on mobile application |
| Data Collection | Study data is saved on device flash memory then | Study data is wirelessly transferred through Bluetooth from |
| transferred to PC via USB cable. Data can be accessed | the device to a mobile application. Data is then uploaded to | |
| by zzzPAT software and uploaded to CloudPAT web | Nexus360 web server for storage and analysis. | |
| server. |
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Image /page/11/Picture/0 description: The image shows the logo for Compumedics. The logo features a stylized "C" with a smaller "m" inside it, followed by the word "COMPUMEDICS" in blue, sans-serif font. Below the company name is the tagline "Defining Life's Signals".
Table 4: Comparison of Technological Characteristics
Conclusion
Compumedics Ltd. considers the Somfit to be substantially equivalent to its predicate device the Watch-PAT300. The intended use as an HSAT device are identical. The fundamental principles of operation are the same, and where differences exist they have been discussed. There are no questions of safety and effectiveness, and substantial equivalence is supported by extensive performance testing and clinical data.
§ 868.2375 Breathing frequency monitor.
(a)
Identification. A breathing (ventilatory) frequency monitor is a device intended to measure or monitor a patient's respiratory rate. The device may provide an audible or visible alarm when the respiratory rate, averaged over time, is outside operator settable alarm limits. This device does not include the apnea monitor classified in § 868.2377.(b)
Classification. Class II (performance standards).