Design and Implementation of a Neonatal Warming Blanket with Temperature Regulation Functionality

Author: Morgan Warneford

Warneford, Morgan, 2019 Design and Implementation of a Neonatal Warming Blanket with Temperature Regulation Functionality, Flinders University, College of Science and Engineering

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Core body temperature needs to be within a normothermic range, but premature neonates may have trouble regulating their own body temperature, as they have an underdeveloped autonomic nervous system. If the neonate is using energy to maintain a normal body temperature, this means that growth and development of the neonate is likely to be reduced. This is of crucial importance with premature neonates due to their inability to stay warm, and their smaller size (Okken, 1991).

Neonatal enclosed incubators, or open radiant warmers, are commonly used to ensure normothermic body temperature. Neonatal staff usually select a desired body temperature for the neonate and the heater output energy is automatically managed to maintain this desired body temperature. Enclosed incubators may also provide supplemental humidity and oxygen and help reduce external noise and light from the hospital environment (Bird, 2018). However, while neonatal incubators are ideal in terms of temperature regulation and environmental control, they prevent contact between parents and the neonate, and this can lead to adverse emotional and physical affects.

During extended hospital stays, neonates are rarely able to be cared for full-time by their family and this may lead to depression and anxiety in parents. Furthermore, neonates from the Neonatal Intensive Care Unit (NICU), once older, are also more likely to display “less adaptability, greater impulsiveness, more temper tantrums, shorter attention span, increased rigidity (and) decreased smiling,” (Hunt, 2011).

The output of the thesis has the potential to reduce the occurrence of temperature-related neonatal problems and to increase the development of these neonates, both mentally and physically. Kangaroo care may also become more common, and this would increase the wellbeing of the neonate and parents or guardians during this crucial development stage.

Kangaroo care provides many benefits including (Brusie, 2017):

● Stabilised infant weight

● Lower rates of infection

● Lower mortality rates

● Higher breastfeeding rates

● Increased bonding

● Increased milk supply

● Decreased stress in the baby

Furthermore, the increased contact between neonates and parents has led to in-hospital benefits such as “shorter hospital stays for babies and increased staff satisfaction for doctors and nurses looking after the babies” (Circle Of Care Optimising Outcomes for Newborns (COCOON), no date).

As an additional benefit, the incorporation of humidity monitoring in a new design could prove significant in terms of pressure sore prevention and maintenance. Literature supports the idea that humidity plays a significant role in pressure sore formation (Suriadi et al., 2008), so real-time humidity data can ensure that any initial sores will be quickly identified, and rectified.

The heart rate of the neonate will also be monitored as heart rate is a significant indicator of wellbeing in neonates. As will be discussed in the thesis, heart rate can also be an indicator of the risk of infant mortality due to Sudden Infant Death Syndrome (SIDS).

The project will also lead to the production of a blanket which is more flexible and less labour intensive than those currently available in the market. Any time spared in the NICU is beneficial as the neonates are in such a fragile health state, and require continuous monitoring and care. The design considers the delicate and complex network of factors that need to be monitored and controlled to support the life of a premature or very low birth weight neonate. These factors include the temperature and humidity of the surrounding environment, as well as the heart rate and core body temperature of the neonate. The designed blanket also aims to incorporate the sensing and monitoring capabilities of neonatal incubators while maintaining the portability and flexibility of neonatal warming blankets.

The temperature output of the blanket is monitored and regulated using a compensation system. This sets the design apart from others in the market as the temperature of the embedded heating elements varies depending on the temperature of the neonate at a given time. Visual and audio alarm systems have also been put in place to ensure the safety of the neonate. The introduction of this design at the Flinders Medical Centre (FMC) is expected to decrease the temperature-related neonatal complications in the NICU.

To design and create the neonatal warming blanket, continuous dialogue was maintained between the student, FMC staff and the student’s academic supervisor. A dedicated Printed Circuit Board (PCB) was designed and built which enabled all components to be mounted on one electronic board. Software was then written by the student which provided a means of interacting with the PCB and components, in order to obtain humidity, pulse and temperature data relating to the neonate and their surrounding environment.

Testing of each sensing component was carried out to determine the accuracy of each sensor relative to a known reference. However, testing on neonates in the NICU was outside the scope of this project. As a result of this thesis, a functional warming blanket prototype was constructed which successfully integrated humidity, pulse and temperature sensors. The accuracy of these sensors was verified using sensors of known accuracy, such as those used in the hospital environment.

It is important to note that the project objective was to design a prototype, and there are still areas that could be developed further in future work. While clinical testing was outside the scope of this project, this will be the next step in ensuring the safety of the neonate, parents and neonatal staff using the blanket in the future. In addition to this, increased budget in the future could lead to more comprehensive analysis into the sensors available in the market. This could, in turn, improve the overall accuracy of the sensors in the system.

Keywords: Design, neonate, PID algorithm, temperature regulation, warming blanket

Subject: Engineering thesis

Thesis type: Masters
Completed: 2019
School: College of Science and Engineering
Supervisor: Kenneth Pope