Study subjects.

<p>(A) Study subjects for the perinatal and neonatal factors related to LCC. (B) Study subjects for the center variation in the incidence of LCC. VLBW, very low birth weight; LCC, late-onset circulatory collapse; EP, extremely preterm.</p

Neonatal factors related to center variation in the incidence of late-onset circulatory collapse in extremely preterm infants

<div><p>Background</p><p>Although late-onset circulatory collapse (LCC) is widely recognized in Japan, its etiology and the reason for center variation in its incidence remain unclear. This study’s objectives were to identify the perinatal and neonatal factors related to LCC and to estimate the factors related to the center variation in the incidence of LCC.</p><p>Methods</p><p>Extremely preterm infants born between 2008 and 2012 who were registered in the database of the Neonatal Research Network, Japan were retrospectively analyzed. LCC was defined as a clinical diagnosis of LCC and the administration of steroids. We first identified the factors that were significantly related to LCC. We then examined the cause of the center variation in the incidence of LCC, using the standardized incidence ratios (SIRs) of LCC and individual factors.</p><p>Results</p><p>The factors significantly associated with LCC included low gestational age (odds ratio [OR]: 1.13), small for date (OR: 1.43), male sex (OR: 1.26), antenatal steroid use (OR: 1.19), respiratory distress syndrome (OR: 1.25), chronic lung disease at 36 weeks (OR: 1.16), periventricular leukomalacia (PVL) (OR: 2.57), necrotizing enterocolitis (OR: 0.59), retinopathy of prematurity (ROP) (OR: 1.73), high-frequency oscillating ventilation (HFOV) use (OR: 1.31), parenteral nutrition (OR: 1.38), and red blood cell (RBC) transfusion (OR: 1.94). The SIR of LCC ranged from 0.05 to 2.94, and was positively correlated with SIRs of PVL, ROP, HFOV use and RBC transfusion.</p><p>Conclusion</p><p>PVL, ROP, HFOV use and RBC transfusion were found to be correlated with the center variation in the incidence of LCC.</p></div

The relationship between the SIRs of LCC and perinatal and neonatal factors in each center.

<p>SIR, standardized incidence ratio; SFD, small for date; ANS, antenatal steroid use; RDS, respiratory distress syndrome; CLD, chronic lung disease; PDA, patent ductus arteriosus; PVL, periventricular leukomalacia; NEC, necrotizing enterocolitis, ROP, retinopathy of prematurity; HFOV, high- frequency oscillating ventilation; PN, parenteral nutrition; RBC, red blood cell.</p

The perinatal characteristics in the LCC and non-LCC groups and the odds ratios for LCC.

<p>The perinatal characteristics in the LCC and non-LCC groups and the odds ratios for LCC.</p

Neonatal morbidities and interventions in the LCC and non-LCC groups and the odds ratios for LCC.

<p>Neonatal morbidities and interventions in the LCC and non-LCC groups and the odds ratios for LCC.</p