Neonatal Resource Services Clinical Guideline Thermoregulation Guideline Purpose: To explain the importance of the principles of thermoregulation in the NICU
Background
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Definitions
Control of thermoregulation is one of the critically important factors in physiological
maintenance of the neonate in the NICU.
The neonate is no exception to the general rule that body temperature is the result
of a balance between heat production and heat loss.
Heat loss in the neonate, especially the very small premature neonate is the due
to properties of the skin, low insulation (i.e., fat), high evaporation and limited
ability to vasoconstrict.
Importantly, the body surface area is high in relation to weight in the neonate; a
factor that significantly facilitates heat loss in this group.
The ability to maintain normal core body temperature is inversely proportional to
the gestational age of the neonate. The appropriate for gestational age neonate
needs support until approximately 35 weeks corrected gestational age.
Maintenance of thermoregulation in the neonate involves reducing one or more of
the four mechanisms of heat loss: convection, conduction, evaporation and
radiation.
The neutral thermal environment is the range of ambient temperature within which the
metabolic rate is at a minimum and within which the temperature regulation is
achieved by nonevaporative processes alone.
The four mechanisms of heat loss in the neonate include the following:
 Conduction: transfer of heat through the body to the skin surface and from
the skin surface to that which is in contact with the skin
 Convection: transfer of heat at the skin surface to the surrounding air
 Evaporation: transfer of heat from the skin or mucous membranes through
loss of water
 Radiation: transfer of heat from a warmer surface to a cooler surface without
the need for direct contact or an interceding medium
Thermoregulation
 The use of an incubator/radiant warmer to facilitate maintenance of a
thermoneutral environment is routine practice in the NICU until the neonate is
able to maintain his/her own thermoregulatory control .
 A key criterion to determine if the neonate is ready for discharge is his/her
ability to maintain their temperature without incubator/radiant warmer support.
Client Target
Population
Any neonate in the NICU; however, these guidelines are applicable to those neonates
who require assistance in maintaining their neutral thermal environment
Clinical
Management
There is no absolute standard of care for maintenance of a neutral thermal
environment and the subsequent weaning of the neonate from either the incubator or
the radiant warmer. However the following guidelines are in general use in the majority
of NICUs in this country:
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Medical
Director
Escalation
Incubator Temperature: Generally the neonate may be weaned from the
incubator when the temperature of the incubator is less or equal to 28
degrees C
 Corrected Gestational Age: When this parameter reaches approximately 34 36 weeks
 Consistent Weight Gain: A consistent weight gain of 15-20 g/kg/d
 Enteral Feeding: The neonate should tolerate full enteral nutrition
 Apnea, Bradycardia and Desaturations: A/B/D episodes should not require
stimulation
 Cardiovascular Stability: The neonate should evidence cardiovascular
stability; i.e., stable vital signs
The Nurse Case Manager should refer the case to the Medical Director if the neonate
is still in the incubator when the temperature of the incubator is less or equal to 28
degrees C, assuming no skilled nursing services are required.
Best Practices
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Infants < 32 week should be placed on a chemical heating mattress and or in a
polyethylene wrap in the delivery room for transfer to the NICU to improve to
reduce insensible water and improve admission temperature
Weaning should occur prior to achieving full enteral feeds. This proactive
approach has been shown to reduce LOS by an average of ~ 2.5 days.
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Bibliography
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Flenady VJ, Woodgate PG. Radiant warmer vs incubators in newborn infants. Cochrane Systematic Reviews. 2003;
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Gaylord, M, et al. Improved Fluid Management Utilizing Humidified Incubators in Extremely Low Birth Weight Infants.
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Meyer, M, et al. A Clinical Comparison of Radiant Warmer and Incubator Care for Preterm Infants from Birth to 1800
Grams. Pediatrics 2001; 108: 395-401
Sauer PJJ Neonatal Thermoregulation in Cowett RM (editor) Principles of Perinatal Neonatal Metabolism Vol 2
Springer Verlag Pages 1027 – 1044. 1998.
Sutter et al. Weaning of premature infants from the incubator to an open crib. Journal of Perinatology1988: 8:193-198
Neonatal Resource Services Thermoregulation April 2013
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