Ray Lengvilas MD, Joseph Decristofaro MD, Echezona Maduekwe MD
Stony Brook University School of Medicine, Stony Brook, NY
Background: Neonatal resuscitation requires the rapid identification of an accurate heart rate in the delivery room to make critical decisions in the first minutes of life. Many methods are currently utilized for the assessment of heart rate during neonatal resuscitation in the delivery room, but the gold standard is the electrocardiogram (EKG). Despite being reliable and accurate, additional time for lead application, difficult signal acquisition through polyethylene bag, possible damage to fragile skin, and pulseless electrical activity are some of the major disadvantages, especially in very low birth weight (VLBW) newborns. It is therefore, critical to evaluate other monitoring methodologies that could be used in the delivery room to rapidly and reliably identify the heart beat in this population of newborn infants without these issues. Recent studies have shown that handheld Doppler (DA) is a reliable methodology in term newborns. However, its reliability and accuracy in VLBW preterm infants have not been evaluated.
Aim: To evaluate the reliability and accuracy of detecting the heart rate using the handheld DA compared to pulse rate from a pulse oximeter (PO) versus the gold standard EKG in VLBW preterm infants. We hypothesize that handheld DA will be reliable and accurate in monitoring neonatal heart rate when compared to PO and EKG.
Methods: This prospective study based on video recordings of preterm infants' bedside EKG with Massimo PO (GE, Boston, MA), and DA (HADECO Smartdop 45, Kawasaki, Japan) in stable VLBW preterm infants from the Neonatal Intensive Care Unit of Stony Brook University Hospital. One investigator performed all the DA studies with the probe placed at the second intercostal space adjacent to the left sternal edge. A total of 33 patients were required to provide 80% power for an interclass correlation (ICC) >0.9.
Results: Thirty-three preterm infants with gestational age 23.6-29.6 weeks at birth, with a mean weight of 1208 grams (SD ± 362.08) were enrolled from January 2019 - August 2020. We compared 12, 15-second epochs of heart rate detected by PO, DA and EKG (Figure 1). The ICC of PO ranged from 0.83 to 0.98 compared with the ICC for DA range of 0.96 to 0.99. Both the PO and DA demonstrated high reproducibility when compared to EKG, but the medians and interquartile ranges (IQRs) of the difference between DA and EKG were lower than that between PO and EKG. Larger variations were observed in the difference between PO and EKG. In addition, it took <1 second for DA placement to provide a signal.
Conclusion: Based on our findings, the DA can accurately, reliably and rapidly identify the heart rate in VLBW infants. A multi-center randomized controlled study will be required to evaluate the reliability and accuracy of DA in VLBW newborns during resuscitation in the delivery room.
