To the Editor:
We appreciate the thoughtful comments and questions by Drs. Kumar, Yadav, and Meena on our article about exchange transfusion (ET) safety and outcomes in neonatal hyperbilirubinemia [1] and we offer the following clarifications.
In our study [2], the incidence of thrombocytopenia was 18% prior to ET, 46% within 1 day of ET, and 64% within 7 days after ET. The 64% value is cumulative and represents thrombocytopenia at any point within the first 7 days after ET. As previous studies have demonstrated, thrombocytopenia peaks ~24 h after ET; therefore, more thrombocytopenia may be appreciated on day 2 following ET, leading to the increase from 46% to 64% [3, 4].
Similarly, hypocalcemia within 7 days is cumulative and represents hypocalcemia at any point within the first 7 days after ET. In our study, 1% of infants developed hypocalcemia within 24 h of ET and 2% developed hypocalcemia within 7 days. Consequently, additional infants develop hypocalcemia more than 24 h after ET, and this ongoing development of hypocalcemia is similar to observations from prior studies [4].
Regarding ongoing hyperbilirubinemia at day 7 after ET in late preterm and term infants, the bilirubin values in our study represent the median and are cumulative over the 7-day time course; 996 infants had bilirubin values in the first day following ET and 1076 infants had bilirubin values in the first 7 days after ET. Overall, there was a slight decrease in median bilirubin level (mg/dL) after ET, with stable maximum levels between 1 and 7 days following ET.
Finally, not all infants, especially those who were term, remained in the hospital at 7 days after ET. The median time between ET and discharge was 8 days (25–75th percentile: 4–20 days). Thank you for the opportunity to respond to these comments and questions.
Compliance with ethical standards
Conflict of interest
RGG has received support from industry for research services (https://dcri.org/about-us/conflict-of-interest/). The authors have no other conflicts of interest relevant to this article to disclose.
Footnotes
High school or college student affiliated with the Duke Clinical Research Institute’s R25 Summer Training in Academic Research (STAR) Program.
References
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