The Belun Sleep System BLS-100 is a wearable device intended to record, analyze, display, export, and store biophysical parameters to aid in evaluating moderate to severe sleep-related breathing disorders suspected of sleep apnea. The device is intended for use in clinical and home settings under the direction of a Healthcare Professional (HCP).

Device Description

The Belun Sleep System BLS-100 comprises a sensor that is worn on the proximal phalanx of index finger (Belun Ring) over-night whilst the subject is sleeping and a stand-alone analysis software (Belun Sleep AI). The Belun Ring has a small biocompatible enclosure. The sensor has 2 LEDs, one in the red spectrum and the other in the infrared spectrum, and an accelerometer. The sensor is placed on the proximal phalanx of the index finger, with the sensor window applied against the palmar side of the proximal phalanx of the index finger. The sensor measures the reflected red/infrared signals to record the photoplethysmograph (PPG) signal. The accelerometer is used to detect movement. The data recorded by the Belun Ring is stored in device on-board memory. The data is exported when the Belun Ring is returned to the prescribing HCP via USB or Bluetooth and passed to the Belun Sleep AI Software, which is standalone PC software. The Belun Sleep Al loads and processes the signal from the exported data and generates the apnea-hypopnea index (bAHI) and sleep staging identification (bSTAGES).

AI/ML Overview

Let's break down the information regarding the acceptance criteria and the study that proves the device meets them for the Belun Sleep System BLS-100.

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria are implicitly defined by the clinical study results being presented as sufficient evidence for clearance. While explicit "acceptance criteria" are not listed as pass/fail thresholds in a formal table, the provided performance metrics represent the device's demonstrated capabilities.

Here's a table summarizing the reported device performance, which the FDA accepted as evidence of substantial equivalence:

Metric (Implicit Acceptance Criteria)	Performance (Belun Sleep System BLS-100)
AHI Accuracy (at cutoff 15)	0.877
AHI Sensitivity (at cutoff 15)	0.898
AHI Specificity (at cutoff 15)	0.860
AHI Accuracy (at cutoff 30)	0.925
AHI Sensitivity (at cutoff 30)	0.840
AHI Specificity (at cutoff 30)	0.951
Sleep Stage Accuracy (Wake)	0.885
Sleep Stage Sensitivity (Wake)	0.604
Sleep Stage Specificity (Wake)	0.961
Sleep Stage Accuracy (REM)	0.908
Sleep Stage Sensitivity (REM)	0.712
Sleep Stage Specificity (REM)	0.944
Sleep Stage Accuracy (NREM)	0.827
Sleep Stage Sensitivity (NREM)	0.904
Sleep Stage Specificity (NREM)	0.695
Mean difference between bTST and PSG-TST	21.8 minutes
Standard deviation of difference between bTST and PSG-TST	41.6 minutes
Mean absolute difference between bTST and PSG-TST	30.8 minutes

2. Sample Size and Data Provenance

Sample Size for Test Set: 106 patients suspected of obstructive sleep apnea (OSA).
Data Provenance: The study compared the device's performance against overnight polysomnography (PSG) studies conducted in a sleep laboratory. The location of the sleep laboratory (country of origin) is not explicitly stated in the provided text. The study design implies this was a prospective collection of data for this evaluation, as it describes patients going through a study with both the Belun device and PSG.

3. Number of Experts and Qualifications for Ground Truth

Number of Experts: At least two experts, as the text states "a senior sleep tech scorer and reviewed by a board-certified sleep physician."
Qualifications of Experts:
- One "senior sleep tech scorer."
- One "board-certified sleep physician."

4. Adjudication Method for the Test Set

The adjudication method used to establish the ground truth for the test set was: "All sleep studies were manually scored based on the AASM scoring manual (version 2.4) by a senior sleep tech scorer and reviewed by a board-certified sleep physician." This indicates a two-step process where one scorer performs the primary scoring, and a physician provides a review, implying a form of consensus or verification, though not a multi-reader disagreement resolution specifically.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No, a multi-reader multi-case (MRMC) comparative effectiveness study was not done. The study focuses on the standalone performance of the device's AI algorithms (bAHI and bSTAGES) compared to PSG ground truth, not on how human readers' performance improves with or without AI assistance.

6. Standalone Performance

Yes, a standalone (algorithm only without human-in-the-loop performance) study was done. The clinical study section directly reports the accuracy, sensitivity, and specificity of the Belun Sleep System BLS-100's AHI and sleep staging calculations compared to PSG results, indicating the performance of the device's algorithms themselves. The statement "All investigators, sleep lab team, and scorers were blinded to the results until statistical analysis was performed" further supports that the device's output was generated independently.

7. Type of Ground Truth Used

The type of ground truth used was expert consensus based on Polysomnography (PSG) studies, manually scored according to the American Academy of Sleep Medicine (AASM) guidelines (version 2.4) by a senior sleep tech scorer and reviewed by a board-certified sleep physician.

8. Sample Size for the Training Set

The document does not explicitly state the sample size for the training set used for the Belun Sleep AI's deep-learning algorithms. It only provides details for the clinical validation (test) set.

9. How the Ground Truth for the Training Set Was Established

The document does not explicitly state how the ground truth for the training set was established. It mentions that the clinical evaluation "confirmed that the Belun Sleep System deep-learning algorithms calculating the Belun Apnea Hypopnea Index (bAHI) and Belun Sleep Stage (bSTAGES) generate comparable output to human manual scoring of an Apnea Hypopnea Index (AHI) from Polysomnography (PSG) studies, using American Academy of Sleep Medicine (AASM) scoring guidelines for adult patients". While this describes the validation against PSG ground truth, it doesn't detail the ground truth establishment process for the data used to train the AI models.

Summary

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February 23, 2023

Belun Technology Company Limited Leung Lap Wai Lydia CEO Unit 218, 2/F, Core Building 2, No. 1 Science Park West Avenue, Hong Kong Science Park Sha Tin, Hong Kong China

Re: K222579

Trade/Device Name: Belun Sleep System BLS-100 Regulation Number: 21 CFR 868.2375 Regulation Name: Breathing Frequency Monitor Regulatory Class: Class II Product Code: MNR Dated: January 10, 2023 Received: January 13, 2023

Dear Leung Lap Wai Lydia:

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 (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 located 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.

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

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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 803) for devices or postmarketing safety reporting (21 CFR 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 (OS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.

Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 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 mediation-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,

Rachana Visaria -S

Rachana Visaria, Ph.D. Assistant Director DHT1C: Division of Sleep Disordered Breathing, Respiratory and Anesthesia Devices OHT1: Office of Opthalmic, Anesthesia, Respiratory, ENT and Dental 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) K222579

Device Name Belun Sleep System BLS-100

Indications for Use (Describe)

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

This summary of 510(k) is being submitted in accordance with the requirements of 21 CFR 807.92 on 23-Feb-2023.

l. SUBMITTER

Belun Technology Company Limited Address: Unit 218, 2 Floor, Core Building 2, 1 Science Park West Avenue, Hong Kong Science Park, Shatin, Hong Kong Contact Person: Leung Lap Wai Lydia Phone: +852 706 5640

II. PROPOSED DEVICE

Trade/Device Name: Belun Sleep System BLS-100 Model: BLS-100 Classification Name: Ventilatory Effort Recorder Regulation Number: 21 CFR 868.2375 Regulatory Class: II Product Code: MNR

PREDICATE DEVICE III.

Device Name: NightOwl (K220028) Classification Name: Ventilatory Effect Recorder Regulation Number: 21 CFR 868.2375 Regulatory Class: II Product Code: MNR

IV. DEVICE DESCRIPTION

The Belun Sleep System BLS-100 is prescribed by a Health Care Professional (HCP) for the patient to use in the home as a 'home sleep apnea test' (HSAT).

The Belun Ring has a small biocompatible enclosure. The sensor has 2 LEDs, one in the red spectrum and the other in the infrared spectrum, and an accelerometer. The sensor is placed on the proximal phalanx of the index finger, with the sensor window applied against the palmar side of the proximal phalanx of the index finger.

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The sensor measures the reflected red/infrared signals to record the photoplethysmograph (PPG) signal. The accelerometer is used to detect movement.

The data recorded by the Belun Ring is stored in device on-board memory. The data is exported when the Belun Ring is returned to the prescribing HCP via USB or Bluetooth and passed to the Belun Sleep AI Software, which is standalone PC software. The Belun Sleep Al loads and processes the signal from the exported data and generates the apnea-hypopnea index (bAHI) and sleep staging identification (bSTAGES).

Signals from the Belun Ring device include the following:

. Oxygen saturation
Beat-to-beat pulse period
Photoplethysmography
. Actigraphy

V. INDICATIONS FOR USE

The Belun Sleep System BLS-100 is a wearable device intended to record, analyze, display, export, and store biophysical parameters to aid in evaluating moderate to severe sleep-related breathing disorders of adult patients suspected of sleep apnea. The device is intended for use in clinical and home settings under the direction of a Healthcare Professional (HCP).

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COMPARISON OF TECHNOLOGICAL CHARACTERISTICS WITH THE PREDICATE DEVICE AND THE REFERENCE DEVICE VI.

Table 1 Performance Specification Comparison Table between the Belun Sleep System BLS-100 and Predicate Device
Characteristic	Proposed DeviceBelun Sleep System BLS-100	Predicate DeviceNightOwl (K220028)	Comparison
Regulation No.	21 C.F.R. 868.2375	21 C.F.R. 868.2375	Identical to predicate device
Classification	ll	ll	Identical to predicate device
Classification Name	Breathing frequency monitor	Breathing frequency monitor	Identical to predicate device
Product Code	MNR	MNR	Identical to predicate device
Intended Use	The Belun Sleep System BLS-100 is awearable device intended to record,analyze, display, export, and storebiophysical parameters to aid inevaluating moderate to severe sleep-related breathing disorders of adultpatients suspected of sleep apnea.The device is intended for use inclinical and home settings under thedirection of a Healthcare Professional(НСР).	The NightOwl is a wearable deviceintended for use in the recording,analysis, displaying, exporting, andstorage of biophysical parameters toaid in the evaluation of sleep-relatedbreathing disorders of adult patientssuspected of sleep apnea. The deviceis intended for the clinical and homesetting use under the direction of aHealthcare Professional (HCP).	Substantially equivalent topredicateThe proposed system and thepredicate have the similarintended use.
Table 1 Performance Specification Comparison Table between the Belun Sleep System BLS-100 and Predicate Device
Characteristic	Proposed DeviceBelun Sleep System BLS-100	Predicate DeviceNightOwl (K220028)	Comparison
Use Environment	Recording in the home environment with thereport interpretation performed in theclinical setting.	Recording in the home environment with thereport interpretation performed in theclinical setting.	Identical to predicate device
Target population	22 years old and older	22 years old and older	Identical to predicate device
Sensor software	Firmware is limited to control the recordingand communications processes. Nopresentation of test results to the patient.Data analyzed and presented in a separatesoftware suite.	Firmware is limited to control the recordingand communications processes. Nopresentation of test results to the patient.Data analyzed and presented in a separatesoftware suite.	Identical to predicate device
Analysis softwarelocation	Analysis performed off the recording device,exclusively stand-alone by the Belun software	Analysis performed off the recording device,exclusively cloud-based by the NightOwlsoftware	Substantially equivalent topredicateThe software is verified and validated.The difference of the analysis softwarelocation does not raise different questions ofsafety and effectiveness.
Table 1 Performance Specification Comparison Table between the Belun Sleep System BLS-100 and Predicate Device
Characteristic	Proposed DeviceBelun Sleep System BLS-100	Predicate DeviceNightOwl (K220028)	Comparison
Analysis softwarealgorithm - AHI	bAHI calculation tuned to the AASM's '1B Rule' for the scoring of hypopnea	pAHI calculation tuned to the AASM's '1A Rule' for the scoring of hypopnea ANDpAHI calculation tuned to the AASM's'1B Rule' for the scoring of hypopnea	Substantially equivalent topredicateThe clinical evaluation has confirmed thatthe Belun Sleep System deep-learningalgorithms calculating the Belun ApneaHypopnea Index (bAHI) and Belun Sleep
Analysis softwarealgorithm - Sleepstages	bSTAGES: WAKE, NREM and REMbTST calculation (time summation of REM andNREM stages)	Total Sleep Time (TST) calculationTotal REM Time calculation	Stage (bSTAGES) generate comparableoutput to human manual scoring of anApnea Hypopnea Index (AHI) fromPolysomnography (PSG) studies, usingAmerican Academy of Sleep Medicine(AASM) scoring guidelines for adultpatients, with accuracy, sensitivity andspecificity similar to the predicate andreference devices.
Sensors	Optical plethysmography sensor,accelerometer	Optical plethysmography sensor,accelerometer	Identical to predicate device
Battery	3.7V Lithium Battery	Battery powered by coin cell	Substantially equivalent topredicateThe battery safety is verified andvalidated. The difference in battery typedoes not raise different questions of safetyand effectiveness
Characteristic	Proposed DeviceBelun Sleep System BLS-100	Predicate DeviceNightOwl (K220028)	Comparison
Channels	Photoplethysmography (PPG), Pulse rate, Oximetry, Actigraphy	PAT, Pulse rate, Oximetry, Actigraphy	Substantially equivalent to predicateThe proposed system and the predicate
Wearable sensorlocation	The photoplethysmography (PPG) sensor and accelerometer components are worn on the proximal phalanx of index finger.	The photoplethysmography (PPG) sensor and accelerometer components are worn on the fingertip.	use the similar sensors: optical plethysmography sensor and accelerometer. The differences between predicate are that the proposed device feeds PPG whose envelop is similar to the information provided by PAT to its AI algorithms. Also, the PPG sensor and accelerometer components are worn on the proximal phalanx of index finger instead of fingertip. The clinical evaluation has confirmed that the Belun Sleep System deep-learning algorithms calculating the Belun Apnea Hypopnea Index (bAHI) and Belun Sleep Stage (bSTAGES) generate comparable output to human manual scoring of an Apnea Hypopnea Index (AHI) from Polysomnography (PSG) studies. As such, the proposed system does not introduce any change to the safety and effectiveness of the predicate device.Similar to Somnapatch (K183625) which uses PPG instead of PAT to aid in evaluating OSA.

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VII. PERFORMANCE DATA

Non-clinical Test

The proposed device Belun Ring is tested in accordance with the following standards and FDA guidance documents (leveraged from K211407), including:

. IEC 60601-1-2:2014 Medical electrical equipment - Part 1-2: General requirements for basic safety and essential performance - Collateral Standard: Electromagnetic disturbances - Requirements and tests
. IEC 60601-1-11:2015 Medical electrical equipment - Part 1-11: General requirements for basic safety and essential performance - Collateral Standard: Requirements for medical electrical equipment and medical electrical systems used in the home healthcare environment
. IEC 60601-1:2005 + a1:2012 Medical electrical equipment - Part 1: General requirements for basic safety and essential performance
. IEC 62133:2012 Secondary cells and batteries containing alkaline or other nonacid electrolytes - Safety requirements for portable sealed secondary cells, and for batteries made from them, for use in portable applications
. ISO 80601-2-61:2017 Medical electrical equipment -- Part 2-61: Particular requirements for basic safety and essential performance of pulse oximeter equipment
ISO 10993-1:2018, Biological evaluation of medical devices -- Part 1: Evaluation and testing within a risk management process
. ISO 10993-5:2009 Biological evaluation of medical devices -- Part 5: Tests for in vitro cytotoxicity
. ISO 10993-10:2010 Biological evaluation of medical devices -- Part 10: Tests for irritation and skin sensitization
. ISO 10993-10:2010 Biological evaluation of medical devices -- Part 11: Tests for systemic toxicity
. IEC 62366-1:2015 Medical devices — Part 1: Application of usability engineering to medical devices
. BQB Bluetooth qualification
FCC Part 15B & FCC Part 18 certification .
. FDA Guidance for the Content of Premarket Submissions for Software Contained in Medical Devices
. FDA Guidance for the Content of Premarket Submissions for Management of Cybersecurity in Medical Devices
. FDA Guidance for Applying Human Factors and Usability Engineering to Medical Devices: 2016

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The Belun Ring BLR-100X has been validated for low perfusion saturation and pulse rate in K211407. There are no changes in those features or algorithms for clearance of this device to be used as a home sleep apnea test (HSAT).

Clinical Study

The Clinical Test consists of 2 parts:

(1) SpO2 accuracy: This testing was performed in K211407 and leveraged for this submission.
(2) Comparison to PSG sleep lab results: The purpose of this study is to evaluate the accuracy, sensitivity and specificity of the Apnea-Hypopnea Index (AHI) and sleep staging (wake, Rapid Eye Movement (REM) and Non-Rapid Eye Movement (NREM)) of the Belun Sleep System BLS-100 compared with overnight polysomnography (PSG) study according to the American Academy of Sleep Medicine (AASM) guidelines in a sleep laboratory with 106 patients suspected of obstructive sleep apnea (OSA). All sleep studies were manually scored based on the AASM scoring manual (version 2.4) by a senior sleep tech scorer and reviewed by a board-certified sleep physician. All investigators, sleep lab team, and scorers were blinded to the results until statistical analysis was performed. The accuracy, sensitivity and specificity at AHI cutoff 15 and 30 are summarized in the table below.

Cutoff	Accuracy	Sensitivity	Specificity
15	0.877	0.898	0.860
30	0.925	0.840	0.951

The accuracy, sensitivity, and specificity of 3-categorization sleep stages [wake, Rapid Eye Movement (REM) and Non-Rapid Eye Movement (NREM)] are summarized in the table below.

Class	Number ofEpochs	Accuracy	Sensitivity	Specificity
Wake	85471	0.885	0.604	0.961
REM		0.908	0.712	0.944
NREM		0.827	0.904	0.695

The total sleep time (bTST) of the Belun Sleep System BLS-100 is the time summation of REM and NREM stages. The mean difference between bTST and PSG-TST was 21.8 minutes with a standard deviation of 41.6 minutes. The mean absolute difference between bTST and PSG-TST was 30.8 minutes.

VIII. CONCLUSIONS

In conclusion, the proposed device of Belun Sleep System BLS-100 has the same classification information, similar intended use, similar product design and specification as

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the predicated device. According to the results of non-clinical test and clinical study, the proposed device is Substantially Equivalent (SE) to the predicate device.

Regulation Number and Section

§ 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).