egally marketed device. A complete discussion of many of these features can be found in IEC standards documents.
- IEC 601 2 19 Amendment I Medical Electrical Equipment - Part 2: Particular Requirements for Safety of Baby Incubators;
- IEC 601-2-20 Medical Electrical Equipment - Part 2: Particular Requirements for Safety of Transport Incubators;
- ISO 10993-1: 1992 Biological Evaluation of Medical Devices - Part 1: Evaluation and Testing
The following topics are discussed:
- Materials of construction
- Engineering diagrams
- Mode of operations
- Power source
- Heating and cooling mechanism
- Air controlled versus baby controlled
- Supplementary gas connectors
- Physical durability and robustness
- Environmental conditions for proper operations
- Temperature control
- Rise Time
- Air Flow
- Flow rates
- Supplementary Gas control
- Safety features
- Weight capacity
- Fire protection
Thermo-neutrality is one of the major environmental factors affecting a premature or low-birth-weight neonate inside an incubator. Severe temperature differences inside an incubator lead to neonate heat loss, hypothermia and apnoea, which are closely related to air flow and air velocity. (An anatomically correct neonate model is designed using a three-dimensional laser scanner system and a rapid prototyping machine.) Flow visualisations demonstrate that large-scale rotating airflow is produced inside the chamber, and a number of small, stationary eddies are found in regions between the air inlet and the neonate. Hot-wire measurements show that air velocities along the long inlets are not uniform. Computational fluid dynamics show relatively uniform temperatures of about 34 degrees C on the neonate's anterior aspect and the highest temperature of 36.1 degrees C at the right armpit and the crotch. Flow fields from airflow visualisations, hot-wire measurements and computational fluid dynamics are very similar, both qualitatively and quantitatively. The small eddies produced between the neonate and the mattress could interfere with convective and evaporative heat transfers from the neonate. Therefore it is important to eliminate eddies around the neonate in the design of neonatal incubators.
Biocompatibility of materials
Biocompatibility testing is required for all parts of the device that have direct or indirect contact the patient and is performed to determine the potential toxicity that can result from contact of the component materials of the device with the patient's body. The materials used in the construction of the device should not, either directly or indirectly through the release of their material constituents, produce unreasonable risk of adverse local or systemic effects; be carcinogenic; or cause adverse reproductive and developmental effects.
The evaluation of any new device intended for human use requires data from systematic testing to ensure that the benefits provided by the final product will exceed any potential risks produced by device materials. Biocompatibility testing is indicated when a "new" or non-conventional material or chemical component is incorporated into a device and there is no known appropriate predicate use or for which the safety or effectiveness of the resulting formulation is in question. These materials or chemical components include plastics, metals, colorants, plasticizers, germicides, and chemical or other treatments of the device or device components.
Biocompatibility testing should be performed on the finished product, using test conditions simulating as closely as possible actual patient use. Materials and chemical components that have already been incorporated in legally marketed devices with similar conditions of use, or have a demonstrated history of safety and effectiveness may not require biocompatibility testing; however, the biocompatibility of these materials and chemical components should be fully discussed to support the lack of testing. (Refer to ISO-10993-1:1992, Part I "Biological Evaluation of Medical Devices, Evaluation and Testing", and the FDA-modified Matrix to identify the types of b