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The Noble Anesthesia-Air Snor-Scope Plus™ Electronic Stethoscope is intended as a diagnostic aid in patient monitoring, diagnostics, and treatment under the same conditions that would otherwise require the use of an acoustic (non-clectronic) stethoscope.

In addition, the Noble Anesthesia-Air Snor-Scope Plus Electronic Stethoscope is also intended for electronically amplifying sounds of evolving obstruction of the upper airway in patients without an endotracheal tube undergoing sedation or general anesthesia care professional.

It is not intended to be used for diagnosis and treatment by unlicensed, untrained, or unqualified medical persons.

The Noble Anesthesia-Air Snor-Scope Plus™ Electronic Stethoscope System is a kit comprised of the following components:

• Audio amplifier module and microphone
• Plastic T-connector / diaphragm coupler assembly (airway adapter)
• Single Plastic coupler (stethoscope adapter)
• Stethoscope Head (standard mechanical acoustic)
• Stethoscope (standard mechanical acoustic)
• Wall charger (UL listed, medical grade) and eight (8) batteries (rechargeable)

A shielded microphone and audio cable, with a 3.5mm plug, connects the microphone/coupler assembly to the amplifier module. The speaker volume may be adjusted on the audio amplifier module to allow comfortable listening levels of breathing sounds passing through the airway circuit for Anesthesia Physicians and Clinical Personnel. A standard stethoscope ear piece may also be used for private listening purposes, although it does not provide the same amplification as in electronic stethoscope mode.

The Snor-Scope Plus T-connector is composed of a plastic diaphragm and connector cap which holds the diaphragm tightly in place. This T-connector serves as an attachment for either the manual stethoscope (without head) or to the electronic stethoscope microphone. The device is not sterile, is outside the surgical field, and is a single-use disposable accessory.

A single plastic medical grade coupler may also be used as an interface between the Snor-Scope Plus microphone and standard stethoscope dual-diaphragm head for the same purpose that would otherwise require an acoustic (non-electronic) stethoscope.

The Noble Anesthesia-Air Electronic Stethoscope provides 20 times greater signal amplitude than a standard acoustic stethoscope. The overall frequency response is 15 - 1500 Hertz. This stethoscope is a stand-alone unit, has no software, and operates using an analog audio system without introducing any signals or energy into the patient or anesthesia breathing circuit.

The Amplifier Module is powered by rechargeable Nickel Cadmium Batteries which can be easily replaced. The charger consists of a medical grade UL listed wall adapter. The batteries and charger are of the overall packaged kit. The audio amplifier module controls charging which cannot be performed during use of the Noble Anesthesia-Air Snor-Scope Plus™ Electronic Stethoscope.

Here's a breakdown of the acceptance criteria and the study details for the Snor-Scope Plus Electronic Stethoscope, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

• No major external or internal damage (for disposition "Continue tests until final release") | Unit #1 (S/N: 0103): Scratched (X-axis), None (Y-axis), Dent - Corner (Z-axis). No Internal Damage. Passed functional test (Volume Control OK, Connectors OK, Speaker OK).
  Unit #2 (S/N: 0107): None (X-axis), Scratched (Y-axis), Hairline Crack - Corner (Z-axis). No Internal Damage. Passed functional test (Volume Control OK, Connectors OK, Speaker OK. Crack did not affect function).
  Unit #3 (S/N: 0124): None (X-axis), None (Y-axis), Dent - Corner (Z-axis). No Internal Damage. Passed functional test (Volume Control OK, Connectors OK, Speaker OK).

Overall Conclusion stated: "No Internal Damage [...] Disposition: Continue tests until final release. Certified by: [Signature] Date: 01/12/2009" |
| T-Connector Assembly Pressure Test:

• The diaphragm of the Stethoscope-Connector cannot fail (rupture or leak) after being subjected to 25 cycles of 90 cm of water pressure (double the extreme of clinically used pressures: Max PEEP = 30 cm H2O, Max Added PPV = 60 cm H2O). | The text states: "The diaphragm of the Stethoscope-Connector cannot fail after being subjected to 25 cycles of 90 cm of water pressure of the ventilator, i.e., the diaphragm is not ruptured and no leak is produced." This is presented as the criteria for the test, and the "Discussion" section for the T-Connector Test Protocol implies successful completion: "It is possible, but not likely, that the T-connector diaphragm might rupture and cause an anesthesia circuit leak. This occurrence would be detectable by routine pressure checks of the breathing circuit and by listening for a leak over the connecting port of the stethoscope." (This implies it didn't rupture during testing according to the criteria). |
  | Hazardous Conditions Test Protocol - Liquid (Normal Test - Current Leakage):
• No current leakage with or without the charger plugged in under normal operating conditions. | "Test results from these tests have indicated that there is no current leakage, with or without the battery charger plugged in, under normal operating conditions. The unit case and microphone/Tconnector assembly impedance is infinite." |
  | Hazardous Conditions Test Protocol - Liquid (Destructive Test - Current Leakage with Sodium Chloride solution):
• If internal PC board power components are shorted, the micro fuse (Fast Acting, 750 mA, One Time) should indicate no continuity (open circuit) and leakage current should be 0.0mA within ~2-3 seconds.
• With charger plugged in, slight current leakage 0.02 mA - 0.03 mA acceptable before fuse opens.
• Without charger plugged in, current leakage ~0.01 mA acceptable before fuse opens. | "During destructive testing, there was slight current leakage between 0.02 mA - 0.03 mA with the battery charger plugged in... If the internal PC board power components were shorted by the sodium chloride solution, the micro fuse [...] indicated no continuity (open circuit) and leakage current was 0.0mA. Without the battery charger plugged in, current leakage was between 0.01 mA on average. Same micro fuse conditions were found (open circuit) if power components were shorted by the sodium chloride solution. Fuse open time was approximately 2 - 3 seconds as indicated by 0.0 mA current leakage measurements." |
  | Clinical Performance (Detection of Airway Obstruction):
• Accurate detection of stridor in patients undergoing sedation. | "The stridor that was reported in the results was accurately detected by the Snor-Scope Plus." (from the "Pediatric Sedation Outside of the Operating Room" study).
  "The Noble Anesthesia-Air Snor-Scope Plus™ Electronic Stethoscope is a reliable monitor to detect an evolving obstruction of the upper airway." |
  | Safety (Adverse Effects):
• No adverse effects or complications. | "There were no adverse effects or complications." (from the "Pediatric Sedation Outside of the Operating Room" study). |

2. Sample Size Used for the Test Set and Data Provenance

• Clinical Study:
  • Sample Size: 10 patients.
  • Data Provenance: Retrospective, gathered during a study sponsored by Harvard University, San Francisco CA USA, in September 2008. The data was gathered while Dr. James P. Noble was in private practice. The formal study was approved in 2005 by the Western Institutional Review Board (WIRB Protocol #20050216). Patients were "representative of the patient population for which Dr. Noble had cared for over nearly 10 years."
• Drop Test Performance:
  • Sample Size: 3 units (S/N: 0103, 0107, 0124).
  • Data Provenance: Non-clinical bench testing.
• T-Connector Assembly Pressure Test:
  • Sample Size: "Random T-Connector assemblies." (Specific number not provided).
  • Data Provenance: Non-clinical bench testing.
• Hazardous Conditions Test Protocol - Liquid (Current Leakage):
  • Normal Test Sample Size: 5 amplifier module, microphone, and T-connector assemblies.
  • Destructive Test Sample Size: 10 amplifier module, microphone, and T-connector assemblies (5 with charger unplugged, 5 with charger plugged in).
  • Data Provenance: Non-clinical bench testing.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

• Clinical Study: While the study involved 10 patients and aimed to detect stridor, the documentation states "The stridor that was reported in the results was accurately detected by the Snor-Scope Plus." It doesn't explicitly detail how the ground truth of stridor presence was independently established for each patient in the study or by how many experts. However, the study was conducted by or under the supervision of Dr. James P. Noble, who is an Anesthesiologist ("licensed Anesthesiologist only" mentioned in proposed labeling, and his experience in "improving the safety of anesthesia for cosmetic surgery patients" for nearly 10 years before the formal study). The study sponsor/investigator was Robert N. Cooper, M.D.
• Bench Testing: For non-clinical tests (drop, pressure, leakage), the ground truth is determined by the test criteria themselves (e.g., visual inspection for damage, functional testing, resistance/current measurements). The tests were certified by an unnamed individual.

4. Adjudication Method for the Test Set

• Clinical Study: Not explicitly stated for the clinical study. It implies Dr. Noble's clinical assessment was key, given his experience and the device's role in his "special technique." No formal adjudication method like "2+1" or "3+1" is mentioned for establishing the presence of stridor.
• Bench Testing: Not applicable in the same way as clinical studies. The results are objective measurements or observations against predefined criteria.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was Done

• No, an MRMC comparative effectiveness study was not done.
  • The submission focuses on the device's standalone performance and its equivalence to predicate electronic stethoscopes in basic functionality, with an additional indication for detecting upper airway obstruction.
  • The "user testing with Anesthesiologists and Clinicians" for overall effectiveness is mentioned generally but no specifics of an MRMC study are provided.
  • The clinical assay describes a study of 10 patients where the Snor-Scope Plus was used, but it does not compare human readers with and without AI assistance or any other comparative effectiveness with human readers.

6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was Done

• Yes, a standalone performance assessment was done for the core function of detecting stridor.
  • The device is described as an "Electronic Stethoscope" that "electronically amplifies sounds of evolving obstruction." The clinical assay concludes: "The stridor that was reported in the results was accurately detected by the Snor-Scope Plus." This indicates the device, on its own, detected the stridor.
  • The Snor-Scope Plus is an analog audio system; it "has no software, and operates using an analog audio system without introducing any signals or energy into the patient or anesthesia breathing circuit." Therefore, it's not an "algorithm" in the modern sense of AI, but its ability to amplify and present sounds for human interpretation is its standalone function.

7. The Type of Ground Truth Used

• Clinical Study: Clinical observation/assessment by medical professionals (implied to be Dr. Noble and potentially other clinicians involved in the study) for the presence of stridor, linked to "evolving obstruction of the upper airway." The "stridor that was reported in the results was accurately detected by the Snor-Scope Plus," indicating the reported stridor was the ground truth.
• Bench Testing: Objective physical and electrical measurements against predefined benchmarks and safety standards (e.g., integrity after drops, pressure resistance, current leakage measurements).

8. The Sample Size for the Training Set

• Not Applicable / Not Provided.
  • The Snor-Scope Plus is described as operating using an "analog audio system" and "has no software." This implies it is not a machine learning or AI-driven device that requires a training set in the typical sense. Its design is based on established acoustic and electronic engineering principles for amplification.
  • The "nearly 10 years during the development of his special technique" by Dr. Noble, where the Snor-Scope Plus (in various stages) was an "essential part," could be considered a form of informal, long-term development and refinement, but not a formal 'training set' for an algorithm.

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

• Not Applicable. As noted above, there's no indication of a formal 'training set' or 'ground truth' establishment for a machine learning algorithm given the device's analog nature. The development and refinement would have been guided by traditional engineering and clinical experience/observation.

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