Citation

Agourram B, Bach V, Tourneux P, Krim G, Delanaud S, Libert JP. J. Appl. Physiol. (APS Bethesda) 2010; 108(6): 1674-1681.

Affiliation

Université de Picardie Jules Verne, Faculté de Médecine.

Copyright

(Copyright © 2010, American Physiological Society)

DOI

10.1152/japplphysiol.00799.2009

PMID

20224001

Abstract

It is well known that wrapping low-birth-weight neonates in a plastic bag prevents body heat loss. Additional measures include the use of a bonnet, since large amounts of heat can be lost from head region. However, it can be held that this procedure provides too much thermal insulation and thus increases the risk of overheating. The present study sought to assess the time required to reach a warning body temperature (t38 degrees C), heat stroke (t40 degrees C) or extreme value (t43 degrees C) in a mathematical model which consists in calculating the various local heat losses from the body. The simulated heat exchanges are based on the distribution of body surface temperatures measured on preterm neonates exposed at an air temperature of 33 degrees C (relative air humidity: 35%; air velocity: <0.1 m s(-1)) and covered (torso and limbs) or not with a transparent plastic bag. The model was used to compare metabolic heat production with body heat losses when a bonnet (2 mm or 3.5 mm in thickness) covered 10%, 40%, and 100% of the head. Wrapping neonates in a bag (combined or not with a bonnet) does not induce a critical situation as long as metabolic heat production does not increase. When endogenous heat production rises, t38 degrees C ranged between 75 and 287 min, t40 degrees C ranged between 185 and 549 min and t43 degrees C ranged between 287 and 702 min. When this increase is accompanied by a fall in skin temperature, the risk of body overheating is accentuated (37

Language: en