Approximately 15 million babies are born premature each year worldwide, and many of them will depend on incubators and infant warmers to survive.
The medical facility must ensure the equipment is working properly with regular consistent testing. Having accurate and consistent test results, not only means that your patients will have what they need to thrive and survive, but it will also allow you to predict when the equipment will need maintenance, service and parts. This save money, and increases the amount of time the medical device is available for use.
In this article, we review 10 Best Practices for Incubator and Infant Warmer Testing, written by Fluke Biomedical. You can download the complete document here.
But first, a short overview of the equipment components.
(pictured above is the ATOM Medical Infant Incubator)
Incubators are fully enclosed units that include an AC-powered heater, a water container to add humidity, a motorized fan to circulate the warm and humid air throughout the cabin of the incubator, a control valve through which oxygen may be added, and a servo-control to help regulate air temperature (a temperature sensing thermistor taped to the infant’s abdomen).
Radiant Warmers aka Infant Warmers
(pictured above is the ATOM Medical Infant Warmer)
Radiant warmers are usually overhead heating units, consisting of a heat source, skin-temperature sensor, servo-control unit, and both visual and audible alarms. The heating element generates radiant energy in the far IR wavelength region but is limited to prevent thermal damage to the infant.
Dual Incubators/Infant Warmer & Transport Incubators
(pictured above ATOM Medical's Dual Infa, infant warmer & transport incubator)
Dual incubators/infant warmer & transport incubators offer a combinationl of customizable features, with advanced components that are able to be moved, broken down, and transported for different modes of use.
Without further ado, here are:
Fluke Biomedical’s 10 best practices for infant incubator and radiant warmer testing
View the complete document here.
1. Always test to the standards.
A manufacturer’s service manual will contain procedures specific to the maintenance and performance of the device, and typically recommend an inspection frequency. You can also check national international standards, as well as The International Electrotechnical Commission (IEC), for uniform and universal testing procedures for biomedical, service, and design engineers.
2. Adopt a consistent inspection frequency.
Most manufacturers recommend a minimum inspection frequency of once per year, as does the. Inspection Program and Development Procedures by J. Tobey Clark. The University of Vermont. However, a semiannual (2 times per year) testing frequency for incubators, and annual testing for radiant warmers can be appropriately justified.
3. Adopt a formal standardized test procedure.
It is important that the infant incubator and radiant warmer functionality be quantitatively evaluated by comparing it to the applicable medical device standard or manufacturer’s specifications. If the service manual and inspection procedure from the manufacturer is not available, If the manufacturer’s specifications are not known, the IEC 60601-2-19, 60601-2-20, and 60601-2-21 standards are a good place to start.
4. Be mindful of probe placement while testing—especially for temperature and airflow.
Probe placement when testing parameters— especially temperature and airflow—are common mistakes when testing and performing preventative maintenance on infant incubators.
All applicable parameters, including temperature, humidity, airflow, and sound should be ten centimeters above the mattress, which is approximately the height an infant would comprise when lying flat on the mattress in the incubator. Temperature (air convection temperature) and airflow should be measured 10 cm above the mattress in five locations; in the very center of the mattress and in the center of each quadrant. NOTE: The pattern of airflow differs in every model of incubator, so it is important to be familiar with the direction of airflow inside the incubator that is being tested, and place the airflow probe properly to obtain an accurate measurement. For example, a bi- or uni-directional airflow probe needs to be placed perpendicular to the direction of airflow to obtain an accurate reading.
5. Account for warm up time.
The warm up time of the incubator to a steady temperature condition (STC) should be measured, and measurements should be taken both during and after the incubator reaches STC. Simultaneously measuring each parameter both during warm-up time and after STC helps give the end user an insight into how the device is running as a whole, and where problems might be occurring if the incubator is not functioning properly.
6. Pair additional test equipment with your incubator/radiant warmer analyzer for comprehensive testing.
Incubators and Infant Warmers require electrical safety tests, including ground wire resistance and chassis leakage, as well as Spo2 and oxygen-monitoring test. Keep an electrical safety analyzer close by to complete the electrical safety portion of the performance inspection easily.
7. Perform all tests necessary to ensure proper performance
A complete list of tests and criteria can be found in the IEC 60601-2-19 and 60601-2-21 standards for infant incubator and radiant warmer testing, or refer to the manufacturer’s service manual.
Here are the basics:
Make sure the incubator warms up in the time specified in the manufacturer’s manual. Test to ensure the overshoot temperature does not exceed 2 °C of the set point.
Check all surfaces that might touch the infant and make sure the surfaces do not get too hot.
Test to determine when the incubator’s temperature stabilizes, and that it stays at the temperature setting for at least an hour.
Verify the temperature is same throughout the compartment.
Check the accuracy of the temperature indicator, and make sure the temperature control sets the temperature to the correct value.
Measure the skin temperature sensor with a calibrated heater assembly.
When testing radiant warmers, make sure the temperature distribution is accurate—meaning that the average temperature of the mid-point is the same as the average of the other test points.
Test to ensure the temperature control is the actual temperature sensed by the skin temperature probe.
Relative humidity is important for respiratory care and air temperature and must be monitored to minimize heat and water loss.
Check the accuracy of the relative humidity. The incubator value should be ±10 % of what the tester indicates.
High air velocities increase evaporative water loss and heat loss of the patient. Measure the air velocity inside the incubator compartment, and ensure it is ≤ to 0.35 m/s at each location.
Infants have incredibly sensitive ears.
Test to determine if the sound level inside the incubator compartment is below 60 dBA (decibels adjusted). Inside and outside alarm levels should be measured to ensure they are within a safe range, yet still audible over background noise.
Most incubators and radiant warmers double as weighing scales since moving tiny patients can be both difficult for the caregiver, and detrimental to the patient’s health. Measure the scale using a series of calibrated weights to ensure it is accurate.
Check the oxygen concentration to validate it is within the acceptable range, and that the visual and auditory alarms are appropriately activated.
8. Use test automation to quickly perform tests, document measurements, and archive data.
Test standardization helps ensure all testing is completed in a consistent sequence, accurately recorded and archived, and meets regulatory requirements. Test automation can help reduce test time, and even increase efficiency. Other benefits of using test automation to validate the performance and safety of incubators and radiant warmers is data traceability, simplified data extraction for reporting, and reduced human error.
9. Always archive test results.
The best place to archive test result information is in a database or Computerized Maintenance Management System (CMMS). Long-term trending of this statistically relevant information provides the basis for predictive maintenance, which saves money and increases the amount of time the medical device is available for use.
10. Choose to test with an analyzer that you can depend on for complete preventive maintenance and safety testing.
For service, maintenance and repairs in the Caribbean, contact Andar International or make an online request here.
To download Fluke Biomedical’s 10 best practices for infant incubator and radiant warmer testing, click here.
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