Prognostic significance of cerebrospinal fluid cyclic adenosine monophosphate in neonatal asphyxia

Objective: In piglets prolonged asphyxia resulted in decreased cerebrospinal fluid (CSF) 3,5'-cyclic adenosine monophosphate (cAMP) during recovery; this was associated with reduced pial arteriolar responses to stimuli that use cAMP as a second messenger. We hypothesized that asphyxia in human neonates results in decreased CSF cAMP and that low CSF cAMP is associated with abnormal outcome. Design: We studied 27 infants with evidence of hypoxic-ischemic insult; 19 were term (group 1) and 8 were preterm (group 2). The normal values of CSF cAMP were determined from 75 infants with no asphyxia; 44 were term (group 3) and 31 were preterm (group 4). CSF cAMP was measured by using radioimmunoassay procedures. Results: CSF cAMP levels in infants with asphyxia (groups 1 and 2) were 12 ± 9.5 and 7.9 ± 7.1 pmol/mL, respectively, significantly lower than those of groups 3 and 4 (control infants), that is, 21.1 ± 8.7 and 27.1 ± 9.2 pmol/mL, respectively (P < .0001). Among infants with asphyxia, 3 died and 10 had abnormal neurologic outcome. Univariate analysis showed that abnormal outcomes were significantly related to CSF cAMP levels, phenobarbital use, and multi-organ failure. However, only CSF cAMP was retained in the model by stepwise logistic regression. CSF cAMP of 10.0 pmol/mL discriminated between those with normal and those with abnormal neurologic outcome. Low CSF cAMP concentration was associated with abnormal long-term outcome, estimated odds ratio of 12.4 (95% CI, 2.1-109.3; P < .006), and sensitivity, specificity, and positive and negative predictive values of 85%, 69%, 73%, and 80%, respectively. Conclusion: CSF cAMP concentrations were decreased in infants with asphyxia. Low CSF cAMP levels were associated with poor neurologic outcome.