Assessment of Cereal-Grain Warming Pad as a Heat Source for Newborn Transport
Kriangsak Jirapaet, MD, MPH* Veena Jirapaet, DNSc**
Affiliation : *Department of Pediatrics, Faculty of Medicine Siriraj Hospital, Mahidol University **Faculty of Nursing, Chulalongkorn University
Objective : The study assessed warming pad (WP) filled with either mung beans or dry corn used in feeding
livestocks as a heat source for newborn transport. Its use was to compensate for lack of transport incubator or
to employ as a supplemental heat source for warming the infant or incubator when transport made in cold
weather.
Materials and Methods : The WP was made of a strong-cotton-cloth bag (the fabric for making jeans) with a size
of A4 paper sheet. The bag was filled with one kilogram of either mung beans or dry corn (used in feeding
livestocks). The WP was heated in a 800-watts microwave oven for 2 minutes with grains thoroughly mixed
inside to distribute heat evenly and put in a disposable A4-size brown envelope. The temperature at the surface
of the brown envelope with the WP inside was recorded every 5 minutes for 120 minutes to assess which
cereal grain could emit more heat and keep the heat longer. Then the WP was heated in the microwave oven for
1, 11/2 and 2 minutes, placed in the same size of brown envelope and covered with two towels. The temperatures
at the surface of the brown envelope and each layer of towels were recorded with the same frequency and
duration.
Results : The cereal-grain WPs, both mung beans and dry corn, were equally effective in producing heat when
warmed in the microwave oven. The mean maximal temperatures at the surface of brown envelope were too
high for direct application to newborns. The mean maximal temperatures of towels covering the paper enve-
lope with WP heated in the microwave oven for 1 minute were as followed. At the first towel, which was close
to the WP, the mean temperature reached 420 C (107.60 F) in 10 minutes after warming and was maintained >
420 C for 10 minutes. All temperature measurements at the first towel was <420 C at 35 minutes. At 2 hours the
mean temperature of the first towel was 35.60 C (96.10 F) which was higher than room temperature by 5.30 C
(41.50 F). The maximal mean temperature measured at the second towel, representing the infantûs skin contact
surface, was 39.70 C (103.50 F) at 15 minutes of which the peak temperature was 41.00 C (105.80 F).
Conclusion : The cereal-grain WP, when used along with traditional nursing interventions as a heat source
during newborn transport, should be safe with careful handling. It should be heated in the microwave oven
exactly for one minute. A towel is placed above an A4-size brown envelope with the WP inside and the bundled
infant is placed on it. Remove the towel at 35 minutes and lay the bundled infant on the brown envelope. It
should be effective and safe in providing a warm transport for at least 2 hours since the temperature of the WP
at the towel representing skin contact surface is not higher than 420 C (107.60 F) and there is no risk for hot
water leakage.
Keywords : Hypothermia, Heat source, Hot water bottle, Newborn transport, Warming pad, Cereal grain, Burn
