Abstract
Background: In 2015, the neonatal resuscitation guidelines incorporated the use of electrocardiography (ECG) to monitor heart rate of newborns. However, previous studies have indicated that cardiac arrest with pulseless electrical activity rhythm (PEA) may occur in the delivery room, rendering this method problematic.Objective: To evaluate the accuracy of ECG and auscultation to assess heart rate during PEA.Methods: A total of 45 piglets (age 1–3 days, weight 1.7–2.3 kg) were exposed to 30 min normocapnic alveolar hypoxia followed by asphyxia until asystole, achieved by disconnecting the ventilator and clamping the endotracheal tube. During asphyxia, heart rate (HR) was assess using auscultation, ECG, and carotid blood flow (CBF). At the time of asystole (defined as zero CBF) HR auscultated using a neonatal/infant stethoscope was compared to ECG traces.Results: The median (IQR) duration of asphyxia was 325 (200–491) s. In 8 (18%) piglets, CBF, ECG, and auscultation identified asystole. In 22 (49%) piglets no CBF and no audible heart sounds, were observed, while ECG displayed a HR ranging from 17 to 75/min. Fifteen (33%) piglets remained bradycardic (defined as HR of < 100/min) after 10 min of asphyxia, which was identified by CBF, ECG, and auscultation. The overall accuracy of ECG and auscultation in the detection of HR were 51 and 80%, respectively (p = 0.004).Conclusion: In cases with PEA ECG is not superior in correctly identifying HR in newborn piglets.
Highlights
After birth, a newborns heart rate (HR) is assessed to determine the effectiveness of spontaneous respiratory effort and the need for subsequent interventions [1, 2]
Until 2015, auscultation of the precordium was recommended as the preferred physical examination method, and pulse oximetry was recommended as an adjunct to provide a non-invasive, rapid, and continuous assessment of HR during resuscitation [1, 2]
In this of particular importance as we recently described that cardiac arrest with pulseless electrical activity (PEA) was present in ∼50% of neonatal piglets exposed to hypoxia and asphyxia [8]
Summary
After birth, a newborns heart rate (HR) is assessed to determine the effectiveness of spontaneous respiratory effort and the need for subsequent interventions [1, 2]. Identifying a rapid, reliable, and accurate method to measure the newborn’s HR is Heartrate Assessment During Cardiac Arrest critically important [1, 2]. Until 2015, auscultation of the precordium was recommended as the preferred physical examination method, and pulse oximetry was recommended as an adjunct to provide a non-invasive, rapid, and continuous assessment of HR during resuscitation [1, 2]. Several studies reported that a ECG displayed a reliable HR faster than pulse oximetry, and pulse oximetry tended to underestimate the newborn’s HR and might have led to potentially unnecessary interventions [4,5,6,7]. In 2015, the neonatal resuscitation guidelines incorporated the use of electrocardiography (ECG) to monitor heart rate of newborns. Previous studies have indicated that cardiac arrest with pulseless electrical activity rhythm (PEA) may occur in the delivery room, rendering this method problematic
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