(27 days)
The TOF-Watch SX device can be used as an objective monitor using accelerometry for measuring the muscle contraction following stimulation of the respective motorneuron, as a peripheral nerve stimulator (without the objective measuring function) for subjective monitoring or as a nerve location device.
The TOF-Watch SX device is a neuromuscular transmission monitor capable of estimating the degree of neuromuscular block in anesthetized patients. It can be used as an objective monitor using accelerometty for measuring the muscle contraction following a stimulation of the respective motorneuron, as a peripheral nerve stimulator (without the objective measuring function) for subjective monitoring and as a nerve location device utilizing a needle electrode. The TOF - Watch SX device is packaged individually in a neutral carton box. The complete package contains a TOF-Watch SX, an acceleration transducer, a surface electrode cable and a multilingu manual.
This 510(k) submission (K992598) for the TOF-Watch SX does not contain detailed information about acceptance criteria or a specific study proving the device meets those criteria in the way a modern AI/ML device submission would. This document is from 1999, and the regulatory requirements and types of evidence provided for device equivalence were different then.
The submission focuses on demonstrating substantial equivalence to a predicate device (TOF-Watch) based on functional and technological characteristics, rather than on detailed performance metrics with acceptance criteria derived from clinical studies.
Therefore, much of the requested information cannot be found in the provided text. I will indicate where information is not available.
1. Table of Acceptance Criteria and Reported Device Performance
Not available in the provided text, as the submission focuses on substantial equivalence based on feature comparison rather than detailed performance metrics with specific acceptance criteria. The document lists features of the new device (TOF-Watch SX) and compares them to the predicate device (TOF-Watch), implying that if the features are similar or enhanced, the performance is also considered equivalent.
A summary characteristic comparison is provided:
| Features | TOF-Watch | TOF-Watch SX |
|---|---|---|
| Stimulation patterns (monitoring) | ||
| TOF | Yes | Yes |
| PTC | Yes | Yes |
| 1 Hz | Yes | Yes |
| 0.1 Hz | Yes | Yes |
| DBS | Yes | Yes (see P button) |
| TET | Yes | Yes (see P button) |
| TOFS (stimulation with user programmable interval) | No | Yes (1-60 min) |
| P button (user programmable button) | No | Yes (DBS, TET, OFF) |
| Stimulation current range | 0-60mA, ≤ 5 KΩ | 60 mA, ≤ 5 KΩ |
| Stimulation pulse width | 200 µS | 200/300 µS |
| Acceleration transducer | Yes | Yes |
| Calibration of acceleration transducer sensitivity | 1 sequence - auto | 2 sequences - auto |
| Manual sensitivity adj. | No | Yes |
| User programmable alarms: TOF and TOFS | No | 2 (upper & lower) (limits: #/%TOF, OFF) |
| User programmable alarms: ON/OFF | No | Yes |
| Automatic power switch off (after 2 hours of no operation) | Yes | Yes |
| Surface temperature sensor | No | Yes (20-41.5°C) |
| Nerve location – LA | Yes | Yes |
| Current range (Nerve location) | 0-6mA, ≤ 5 KΩ | 0-6 mA, ≤ 5 ΚΩ |
| Pulse width (Nerve location) | 40 µS | 40 µS |
The "reported device performance" is essentially the "TOF-Watch SX" column, indicating the features and specifications it possesses, which are either identical or enhanced compared to the predicate device.
2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
Not available. The submission relies on technological comparison for substantial equivalence, not on specific clinical or performance test data on a "test set" in the context of modern AI/ML device evaluations.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)
Not applicable/available. No "ground truth" establishment by experts is described for a test set in this 510(k) submission.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
Not applicable/available. No test set or adjudication method is described.
5. If a multi-reader multi-case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance
Not applicable. This is not an AI/ML device and no MRMC study is mentioned.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
Not applicable. This is not an AI/ML device. The TOF-Watch SX functions as a standalone monitoring device, but the "standalone performance" concept here refers to AI algorithm performance which is not relevant.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)
Not applicable/available. No explicit ground truth is mentioned. The equivalence is based on the device's functional characteristics and operating principles being similar to a legally marketed predicate device.
8. The sample size for the training set
Not applicable/available. This is not an AI/ML device, so there is no training set mentioned.
9. How the ground truth for the training set was established
Not applicable/available. There is no training set for this device.
§ 868.2775 Electrical peripheral nerve stimulator.
(a)
Identification. An electrical peripheral nerve stimulator (neuromuscular blockade monitor) is a device used to apply an electrical current to a patient to test the level of pharmacological effect of anesthetic drugs and gases.(b)
Classification. Class II (performance standards).