Serum levels of caffeine in umbilical cord and apnea of prematurity

Objective: To determine the influence of presence of caffeine in umbilical cord blood on apnea occurrence. Methods: A prospective cohort study with preterm newborns with birth weight lower than 2,000 g was undertaken. Exclusion criteria were: mothers who received opioids; mechanical ventilation during the first 4 days of life; cerebral and major cardiac malformations; perinatal asphyxia; severe periintraventricular hemorrhage; exchange transfusion before the fourth day of life; and those who received methylxantine prior to extubation, Neonates were divided into detectable and undetectable caffeine in umbilical cord blood. Newborns were followed for the first 4 days for occurrence of apnea spells. Results: Eighty-seven newborns with and 40 without detectable caffeine in umbilical cord blood were studied. Median caffeine concentration of the 87 patients with detectable caffeine in umbilical blood was 2.3 mu g/mL (0.2-9.4 mu g/mL). There was no association between occurrence of apnea spells and presence of caffeine in umbilical cord blood. Neonates with detectable caffeine in umbilical blood had borderline later apnea (66.3 +/- 4.14 hours) than those with undetectable levels ( 54.2 +/- 6.26 hours). Conclusion: Detected levels of caffeine in umbilical cord blood did not decrease occurrence of apnea of prematurity, but it had a borderline effect delaying its occurrence, suggesting that even a low level of caffeine in umbilical cord blood might delay occurrence of apnea spells.