mariska+and+nadia

=**//Bioengineers and incubarors by: Mariska C. and Nadia N.//**= Our project was to make a reaserch proposel for desighning incubators. we had to find out about all the difrent aspects of incubators, what premature babies needed to survive, what the cost is and how to make sure the conditions are always right.

**__ The need for mechanical devices to control a premature temperature __** The average body temperature for a newborn is 37o C, a baby has to keep a body temperature of at least 37o C; however, babies remain healthy even at higher temperatures such as 37.5o C without becoming hyperthermic. If the temperature drops below 29oC, the baby may become hypothermic. Medical reviews have proven that a full term baby has a fully developed temperature control system. A premature baby’s temperature control system, however, is not fully developed and needs help to survive until its temperature system has fully developed. Babies born 12+ weeks premature easily loose body heat and become dangerously cold. They are unable to shiver and their brown fat deposits are smaller than that of a full term baby (brown fat insulates heat and provides energy it is found in the abdominal area and neck). Preemies have a larger surface area to volume ratio than a full term, though their temperature should remain the same. The premature babies do not yet have fully developed skin so the skin is only a few layers thick or the protein keratin which makes skin water tight so for the first 3-4 days after birth there is a large amount of water loss. Babies born 12 -16 weeks prematurely do not increase heat production as the temperature falls below 36.5o C and babies born 8 weeks before expected birth cannot sweat for their first week of life. It is obvious a baby needs a source of heat that is more effective than their own, such as an incubator, which can temporarily replace the human insulation system.



Keeping babies warm It has been found that each preemie has its own ideal range of environmental temperature. If the infant is kept within its preferred range it uses the minimum amount of heat energy and oxygen is released during respiration to keep its temperature normal. We call this the neutral thermal environment. The neutral thermal environment for a small unclothed baby is very low. Glass et al showed that babies kept within the neutral thermal energy range develop and gain weight significantly faster than babies who do not. It has now also been shown that it is not only more efficient for the babies’ survival but a necessity. Mestyan et al found the neutral thermal environment of babies according to their masses; he found that babies weighing between 1.5 and 2kg need a neutral thermal environment of at least 34.5oC and babies weighing less than 1.5Kg need a neutral thermal environment of at least 36oC. The aim of this is to keep the skin temperature at a regulated temperature of 36.5oC. Hey produced a table of neutral thermal environment values to assist in finding the ideal range of environmental temperature for preemies according to their temperatures. Doctors can use the graph to find the most appropriate temperatures for the baby; this has been proven very useful. Unfortunately it is not always useable, in cases where the preemie is ill the temperature necessary for its survival will change and babies under 34 weeks old cannot perpetrate however if the child is over heated there is a possibility of water leaking through the under developed skin, this can be fatal. An unclothed baby transfers heat energy by radiation and convection when inside an incubator. The heat is transferred into the air which in turn transfers it to the hood of the incubator; the hood then transfers the energy back into the air, building and objects in the room. Little tono energy transfers occur by conduction.