Ra. Jonas et al., RELATION OF PH STRATEGY AND DEVELOPMENTAL OUTCOME AFTER HYPOTHERMIC CIRCULATORY ARREST, Journal of thoracic and cardiovascular surgery, 106(2), 1993, pp. 362-368
To examine whether pH management during core cooling is a risk factor
for adverse developmental outcome, we studied 16 children with transpo
sition of the great arteries and intact ventricular septum who underwe
nt a Senning procedure in infancy (median age 32 days, range 2 to 154
days) between 1983 and 1988. Information was collected retrospectively
on many aspects of perfusion, including lowest carbon dioxide tension
during core cooling, duration of core cooling, and duration of circul
atory arrest. The pH strategy changed from pH-stat to alpha-stat in 19
85, resulting in a wide range of pH values and carbon dioxide tension
(34 to 76 mm Hg) during the study period. All children had rapid core
cooling to a rectal temperature of 19.8-degrees +/- 2.7-degrees-C (mea
n +/- standard deviation) and a tympanic temperature of 16.6-degrees /- 3.0-degrees-C. Development was assessed at median age 48.0 (11 to 7
9) months with the Bayley Scales (n = 4, children younger than 30 mont
hs) or the McCarthy Scales (n = 12, children older than 30 months). Th
e mean core-cooling duration was 14.5 +/- 6.2 minutes, circulatory arr
est time was 43.4 +/- 6.6 minutes, and total bypass plus circulatory a
rrest time was 89.7 +/- 12.7 minutes. Lower carbon dioxide tension (al
pha-stat) before onset of circulatory arrest was associated with worse
developmental outcome (r = 0.71, p = 0.002). This relationship remain
ed highly significant when we controlled for sociodemographic and intr
aoperative variables, including core-cooling time, circulatory arrest
time, and total elapsed time. Duration of circulatory arrest was not a
ssociated with developmental outcome. We conclude that when relatively
rapid core cooling is used to achieve hypothermia before circulatory
arrest in young infants, a more alkaline pH strategy such as alpha-sta
t may result in less effective cerebral protection.