11 / Use-Related Risk Analysis Human factors · IEC 62366-1
Critical task analysis for unsupervised home use
Use-error analysis for the Kinetrace R1 under IEC 62366-1, identifying which tasks are safety-critical and which documentation controls carry the mitigation.
DisclaimerKinetrace R1 is a fictional device created for this portfolio. Document numbers, revision history and clinical figures are illustrative. No proprietary or client material is reproduced. The regulatory structure and document conventions are real.
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About this documentUse-error analysis under IEC 62366-1, identifying which tasks are safety-critical and which documentation controls carry the mitigation. Produced jointly with human factors and quality.
4.2 Critical tasks and foreseeable use errors
| Task | Foreseeable use error | Potential harm | Severity | Mitigation |
|---|---|---|---|---|
| Fit band to limb | Patient overtightens strap to resolve a poor-contact indication | Restricted circulation, pressure injury | Serious | Step-level caution at IFU §5 step 4; one-finger clearance stated as the acceptance test; app poor-contact message directs to skin preparation, not tightening |
| Prepare skin | Patient applies lotion before fitting, believing it improves conduction | Signal loss, missed deterioration in recovery | Negligible | Explicit prohibition in IFU §5 step 1 |
| Start session | Patient performs a prescription superseded by the clinician | Strain to recovering muscle | Serious | Software block at 90 days (SRS-036); prescriber name and date shown on start screen (SRS-035) |
| Respond to pain | Patient completes the session despite pain, to maintain the adherence streak | Aggravation of existing injury | Serious | IFU warning §3; in-app stop control available on every exercise screen; adherence streak not broken by a session ended for discomfort |
| Clean electrodes | Patient uses alcohol wipes, assuming medical equipment requires disinfection | Electrode degradation, signal loss | Negligible | IFU caution §3; water-only stated in the cleaning procedure itself |
Design input raised from this analysisThe adherence-streak finding was a documentation problem that became a software change. A warning not to exercise through pain competes with a reward the product itself grants for not stopping. Instructions cannot mitigate a risk the interface creates, so the streak rule was changed and
SRS-041 was raised. Recorded here because the origin of a design input belongs in the usability file.4.3 Tasks selected for summative validation
Tasks scored Serious or above are carried into summative usability validation with 15 representative users per user group, per IEC 62366-1 clause 5.9. The two tasks scored Negligible are addressed by instructions alone and verified by comprehension testing during formative evaluation.
Standards applied
IEC 62366-1
ISO 14971
FDA Human Factors Guidance (2016)
IEC 60601-1-11