International perspectives: Late-onset circulatory collapse in very low-birthweight infants: A japanese perspective

The number of reports of sudden deterioration in blood pressure with concomitant decrease of urine output among extremely low-birthweight (ELBW) infants whose general condition is stable have increased recently in Japan. This disorder is clearly different from an unstable circulatory status during the acute phase soon after delivery. The disorder usually occurs more than 1 week after birth, when the infant's circulatory status already is stable. Blood pressure in such hypotensive infants cannot be restored with volume expanders or inotropic agents; it only improves with glucocorticoid administration. The efficacy of steroids in preterm infants who develop hypotension soon after birth is widely known, but the time of onset of this paroxysmal hypotension is apparently different. Relative adrenal insufficiency is considered to be the primary cause of this late-onset hypotension, but the pathogenesis has not been elucidated definitively. The disease is diagnosed clinically and by exclusion. When hypotension persists, it may aggravate chronic lung disease (CLD) and cause periventricular leukomalacia (PVL), which emphasizes the importance of early diagnosis and treatment.