Background ELBW infants are vulnerable to cold stress during the transition from delivery room to intensive care. Infants produce heat by non-shivering thermogenesis (NST) and should exhibit peripheral vasoconstriction when cold, but little empirical evidence confirms that ELBW infants are capable of peripheral vasoconstriction.
Objective This study evaluated the ability of ELBW infants weighing 400–1000 grams to exhibit peripheral vasoconstriction when body temperatures decreased.
Design/Methods A within subject, multiple case design was used to explore the relationships between body temperature and peripheral vasoconstriction in 10 ELBW infants over their first 12 hours in the NICU. Abdominal temperature (AT) and peripheral temperature (PT) were measured in 1-min. intervals. Peripheral vasoconstriction is defined as AT 2°C above PT as established by Lyon et al. Each infant was evaluated for length of time spent with peripheral vasoconstriction.
Results PT and AT were significantly correlated in each infant. One infant (BW: 880 gms) exhibited peripheral vasoconstriction and one infant (BW 960 gms) had AT 1°C greater than PT. Eight infants (BW: 510–720 gms) did not exhibit peripheral vasoconstriction. Seven infants spent at least 15% of their observations with PT > AT and these infants were most likely to have PT 1–2°C>AT. The peripheral-abdominal temperature difference increased during stressful procedures in some infants.
Conclusions ELBW infants have little ability to vasoconstrict in response to NST. PT were more often > AT and this difference often increased during stressful clinical events. Vasomotor control appears immature at birth in infants <800 grams.