Biocompatibility evaluation of breathing gas pathways in healthcare applications - Part 2: Tests for emissions of particulate matter
1Key Takeaways
This document specifies tests for particulate matter emissions from the gas path of respiratory medical devices and their components or accessories. These tests are intended to quantify particles with a diameter of 0.2 µm to 10 µm that are emitted by the medical device, its components or accessories into the breathable…
2Expert Interpretation
This in-depth analysis of the ISO 18562-2:2017 standard for biocompatibility assessment of particulate emissions from medical device gas pathways includes test methods, limit standards, and implementation recommendations to help manufacturers comply with international standards.
Standard Overview and Scope
ISO 18562-2:2017, a key component of the biocompatibility assessment standards for medical devices, specifically specifies test methods for particulate emissions from the gas flow path of medical devices such as respiratory therapy equipment and anesthesia workstations. The standard applies to the detection of particles in the 0.2μm to 10μm size range and explicitly excludes the assessment of nanoparticles.
Core Test Requirements
| Particle Size Range | Limit Requirements | Test Method |
|---|---|---|
| ≤2.5μm | 12μg/m³ | Single Filter Method/Double Filter Method |
| ≤10μm | 150μg/m³ | Inertial Particle Separator Method |
Note: The limit refers to the U.S. EPA 40 CFR Part 50 standard, which is based on research on the potential hazards of particulate matter to the respiratory and cardiovascular systems.
Test Method Technology Comparison
1. Single Filter Membrane Test System
Applicable to low particulate emission equipment, using a 0.2μm filter membrane to capture all particles. The operating process includes:
- Filter membrane pretreatment weighing
- Device operation at maximum clinical flow rate
- Ensure sampling volume ≥8m³ (detection limit 2.5μg/m³)
- Post-processing weighing to calculate increments
2. Particle Counter Method
Particle number-to-mass conversion calculation is required. Typical density reference values are:
- Plastic parts: 0.9g/cm³
- Metal parts: 2.7g/cm³
Risk Management Requirements
Manufacturers must use a risk management system to assess:
- The expected service life of the device
- The impact of repeated processing/sterilization
- Patient exposure under the worst-case scenario
Key parameters such as the basis for test sample selection and the relationship between test duration and clinical use cycle must be recorded in the technical documentation.
Implementation recommendations
- New device design: It is recommended to meet the standard requirements within 3 years after release
- Existing devices: It is recommended to complete compliance transformation within a 5-year transition period
- Test solution selection: Select the single membrane method (simple device) or the graded test method (complex device) based on the complexity of the device
- Dynamic emission equipment: Multiple tests are required to simulate the use cycle