Acute cardiovascular responses in preterm infants at 34-39weeks of gestational age

摘要

Background: Premature infants demonstrate immature physiological control mechanisms; however their acute cardiovascular control has not yet been widely studied. Aim: The aim of this study was to analyze heart rate (HR) and blood pressure (BP) control in preterm infants. Subjects: Twenty preterm infants with a mean gestational age of 31 ± 2.4 (26-34) weeks at birth were evaluated at a gestational age of 36 ± 1.5 (34-39) weeks. Results were compared to twenty, healthy, full-term, control infants studied at the age of 12 ± 3. weeks. Outcome measures: HR and BP responses to 45° head-up tilt and side motion tests during non-rapid eye movement sleep were analyzed. In addition, HR responses to spontaneous arousals from non-rapid eye movement sleep were evaluated. Results: Preterm infants showed significantly smaller initial HR and BP responses compared with controls in head-up tilt (HR p = 0.0005, systolic BP p = 0.02, diastolic BP p = 0.01) and side motion tests (HR p = 0.002, systolic BP p < 0.0001, diastolic BP p < 0.0001). Furthermore, in tilt tests, preterm infants presented with greater intersubject variability in BP responses than controls (systolic BP p = 0.009, diastolic BP p = 0005). Preterm HR responses to spontaneous arousals were similar to controls. Conclusions: This study indicates immature vestibulo-mediated cardiovascular control in preterm infants compared with term infants. This is seen as attenuated BP responses to side motion test and more labile acute BP control to postural challenge.