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 (COEC). We aimed to trend COEC 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 COEC were compared. Both groups' baseline COEC 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 COEC 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 COEC than the reference. Although there was no significant within-subject alteration of COEC during ibuprofen treatment, there was a between-subject difference indicating non-responders had generally higher COEC.
Conclusions: The changes of COEC during pharmacological closure of PDA is less drastic compared to surgical closure. Infants with PDA had higher baseline COEC compared to those without PDA, and non-responders had higher COEC especially at baseline compared to responders.
Keywords: Cardiac output; Electrical cardiometry; Hemodynamic; Non-invasive monitor; Patent ductus arteriosus; Preterm infant.