(225 days)
The Silent Night II is indicated for use in the diagnostic evaluation of adults with possible Obstructive Sleep Apnea. It is intended to record a patient's respiratory pattern during sleep. The device is designed for prescription use in home screening of adults with possible sleep disorders. Information provided by the device includes the numbers of apneic and hypopneic events and the proportion of these events to the total sleep duration; and snoring levels (in decibels). The device is capable of recording four nights or up to 40 hours for an individual patient, after which time the sleep data are downloaded for provision to the prescribing physician.
The Silent Night™ II is a modified version of the legally marketed Silent Night I. The device is a portable, line-powered ventilatory effort recorder intended for use in the home screening of possible sleep disorders. The metal box has two receptacle connectors: one for input power and another for the microphone cable. The sensing microphone and the ambient noise microphone are located at the distal end of the cable, and are attached to the user by means of a modified conventional plastic oxygen cannula. The sensing microphone, located directly beneath the patient's nose, senses respiratory sounds during sleep. The ambient microphone, angled to the side of the patient's nose, senses room ambient noise and measures snoring levels. The Silent Night II is capable of recording up to four nights of sleep study data. The beginning and end of the sleep study are controlled by the use of the START and STOP buttons, located on the front of the unit. An LCD indicates operational status and has a sound level bar, used by the patient at the beginning of the study to verify adequate sensing of breathing sounds by the device.
The device operates by sensing the sound field (breathing sounds + room ambient noise) via the two microphones. Breathing sounds are extracted from all sounds received. The signals are filtered, analyzed, and processed to differentiate between types of sounds and to classify sounds as regular snoring or breathing, hypopnea, or annes. When beep study is completed, the cumulatively logged data are downloaded by Local Site a personal computer. Specialized software and provides, for each night of the sleep study, information about apneas, hypopneas, and snoring levels.
Here's an analysis of the provided text regarding the acceptance criteria and study for the Silent Night™ II device, formatted to include the requested information:
Acceptance Criteria and Device Performance Study for Silent Night™ II
1. Table of Acceptance Criteria and Reported Device Performance
The provided document describes the clinical evaluation of the Silent Night™ II by comparing it to a predicate device, the Sensormedics Model 4100 Somnostar system, for detecting sleep disordered breathing events. The acceptance criteria are implicitly derived from the "high positive correlation" and "strong positive linear association" stated. Specific numeric thresholds for sensitivity and specificity are not precisely defined in the text, but the study indicates the device met these criteria.
| Acceptance Criteria (Implicit) | Reported Device Performance (Silent Night™ II vs. Sensormedics Model 4100 Somnostar) |
|---|---|
| High positive correlation | "high positive correlation between the measurements obtained by the two devices" |
| Strong positive linear association | "strong positive linear association between the measurements obtained from the two devices" |
| High sensitivity | "indicated a high degree of both specificity and sensitivity" |
| High specificity | "indicated a high degree of both specificity and sensitivity" |
| Efficacy in detecting Disordered Breathing Events | "establish the efficacy of the Silent Night II in detecting Disordered Breathing Events" |
2. Sample Size Used for the Test Set and Data Provenance
- Test Set Sample Size: The document does not explicitly state the number of patients or the exact sample size used for the clinical evaluation. It only mentions "Patients were subjected to sleep laboratory evaluation."
- Data Provenance: The study appears to be prospective as patients were "subjected to sleep laboratory evaluation" where both the Silent Night II and the Sensormedics system were used simultaneously. The country of origin of the data is not specified, but given the submitter is based in San José, CA, USA, and the FDA review, it is highly likely the study was conducted in the USA.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and their Qualifications
- Number of Experts: The document does not specify the number of experts used.
- Qualifications of Experts: The document does not explicitly state the qualifications of the experts. However, given that the ground truth was established by a "standard polysomnograph (the Sensormedics Model 4100 Somnostar system)" and involved simultaneous data gathering, it can be inferred that medical professionals trained in polysomnography and sleep disorder diagnosis (e.g., sleep physicians, registered polysomnographic technologists) would have been involved in interpreting and scoring the Sensormedics data.
4. Adjudication Method for the Test Set
The document does not describe any specific adjudication method (e.g., 2+1, 3+1). The ground truth was established by the Sensormedics Model 4100 Somnostar system, which is a standard polysomnograph. This implies that the output of this established device served as the reference standard.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
A multi-reader multi-case (MRMC) comparative effectiveness study was not done or described in the provided text. The study compares the device's measurements directly against those of a gold-standard polysomnograph, not against human readers using or not using AI.
6. Standalone (Algorithm Only) Performance Study
Yes, a standalone performance study was done. The clinical evaluation directly compared the measurements (number of Apneas and Respiratory Disturbance Index - RDI) calculated by the Silent Night II device to those gathered simultaneously by the Sensormedics standard polysomnograph. This assesses the algorithm's performance without direct human interaction for interpretation of the Silent Night II's raw data, although human expertise would be involved in interpreting the Sensormedics output (ground truth).
7. Type of Ground Truth Used
The ground truth used was polysomnography data, specifically from the "Sensormedics Model 4100 Somnostar system," which is described as a "standard polysomnograph." This is a highly accepted clinical standard for diagnosing sleep disorders.
8. Sample Size for the Training Set
The document does not provide any information regarding a training set sample size. This suggests that if machine learning was involved in the device's development (which is not explicitly clear from the description of signal processing and classification), the details of its training were not part of this 510(k) summary. Given the date of the document (1998), early machine learning techniques might have been used, but explicit "training set" reporting was less common compared to modern AI/ML device submissions.
9. How the Ground Truth for the Training Set was Established
As no training set is mentioned, no information is provided on how its ground truth would have been established.
§ 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).