Baseline cardiac output and its alterations during ibuprofen treatment for patent ductus arteriosus in preterm infants

BACKGROUND: Infants with hemodynamically significant patent ductus arteriosus (PDA) may physiologically compensate with a supranormal cardiac output (CO). As such, a supranormal CO may be a surrogate marker for a significant PDA or indicate a failed response to PDA closure by ibuprofen. Electrical cardiometry (EC) is an impedance-based monitor that can continuously and non-invasively assess CO (CO(EC)). We aimed to trend CO(EC) through ibuprofen treatment for PDA in preterm infants. METHODS: We reviewed our database of preterm infants receiving ibuprofen for PDA closure. Response to ibuprofen was defined as no ductal flow in echocardiography ≤24 h after treatment. Responders were compared with gestational age (GA) and postnatal age matched non-responders and their trends of CO(EC) were compared. Both groups’ baseline CO(EC) were further compared to the reference infants without PDA. RESULTS: Eighteen infants (9 responders and 9 non-responders) with median (interquatile range) GA 27.5 (26.6–28.6) weeks, birthweight 1038 (854–1218) g and age 3.5 (3.0–4.0) days were studied. There were positive correlations between CO(EC) and ductal diameter and left atrium/ aortic root ratio (r = 0.521 and 0.374, p < 0.001, respectively). Both responders and non-responders had significantly higher baseline CO(EC) than the reference. Although there was no significant within-subject alteration of CO(EC) during ibuprofen treatment, there was a between-subject difference indicating non-responders had generally higher CO(EC). CONCLUSIONS: The changes of CO(EC) during pharmacological closure of PDA is less drastic compared to surgical closure. Infants with PDA had higher baseline CO(EC) compared to those without PDA, and non-responders had higher CO(EC) especially at baseline compared to responders.