Effect of limb cooling on peripheral and global oxygen consumption in neonates.
OBJECTIVE
To evaluate peripheral oxygen consumption (VO(2)) measurements using near infrared spectroscopy (NIRS) with arterial occlusion in healthy term neonates by studying the effect of limb cooling on peripheral and global VO(2).


METHODS
Twenty two healthy term neonates were studied. Peripheral VO(2) was measured by NIRS using arterial occlusion and measurement of the oxyhaemoglobin (HbO(2)) decrement slope. Global VO(2) was measured by open circuit calorimetry. Global and peripheral VO(2) was measured in each neonate before and after limb cooling.


RESULTS
In 10 neonates, a fall in forearm temperature of 2.2 degrees C (mild cooling) decreased forearm VO(2) by 19.6% (p < 0.01). Global VO(2) did not change. In 12 neonates, a fall in forearm temperature of 4 degrees C (moderate cooling) decreased forearm VO(2) by 34.7% (p < 0.01). Global VO(2) increased by 17.6% (p < 0.05).


CONCLUSIONS
The NIRS arterial occlusion method is able to measure changes in peripheral VO(2) induced by limb cooling. The changes are more pronounced with moderate limb cooling when a concomitant rise in global VO(2) is observed. Change in peripheral temperature must be taken into consideration in the interpretation of peripheral VO(2) measurements in neonates.
Hassan
I A-A
IA
Neonatal Unit, City General Hospital, Stoke on Trent, UK.
Wickramasinghe
Y A
YA
Spencer
S A
SA
D005260:Female; D005542:Forearm / Q000098:blood supply; D006801:Humans; D007036:Hypothermia, Induced; D007231:Infant, Newborn / Q000097:blood / Q000502:physiology*; D008297:Male; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption / Q000502:physiology*; D010108:Oxyhemoglobins / Q000378:metabolism; D012039:Regional Blood Flow; D019265:Spectroscopy, Near-Infrared; D013696:Temperature
D010108:Oxyhemoglobins; D010100:Oxygen