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A randomised cross-over study of methods of acquiring ECG heart rate in newborns
  1. Madeleine C Murphy1,2,
  2. Laura De Angelis3,
  3. Danielle McCollum1,
  4. Lisa K McCarthy1,
  5. Colm PF O’Donnell1,2,4
  1. 1 Department of Neonatology, National Maternity Hospital, Dublin, Ireland
  2. 2 School of Medicine, University College Dublin, Dublin, Ireland
  3. 3 Ospedale dei Bambini V Buzzi, Milano, Lombardia, Italy
  4. 4 National Children's Research Centre, Dublin, Ireland
  1. Correspondence to Dr Colm PF O’Donnell, Neonatal Intensive Care Unit, The National Maternity Hospital, Dublin 2, Ireland; codonnell{at}

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The 2015 International Liaison Committee on Resuscitation1 treatment recommendations suggest that ECG can be used to provide rapid and accurate estimation of the newly born infant’s heart rate (HR). Studies report that it provides HR quicker than pulse oximetry (PO) in the delivery room (DR).2 3 In addition, a DR study of 53 infants reported that HR measured with PO at birth was significantly lower than that measured with ECG with clinically important differences in the first minutes.4 Pulse oximeters display the HR more quickly when the sensor is applied to the infant before it is connected to the monitor.5 We wished to determine whether connecting the leads before or after application to the infant affected how quickly ECG HR is displayed.

We performed a randomised cross-over study of methods of acquiring ECG in stable infants in our neonatal unit with the approval of our research ethics committee and parental consent. We used the IntelliVue X2 monitor (Philips, Eindhoven, The Netherlands), which incorporates ECG and PO and has a portable device that may be used in the DR (figure 1). Three leads are applied to the infant and connected to the monitor to record the ECG. We compared two methods of acquiring the ECG:

Figure 1

IntelliVue X2 monitor portable device.

  1. Leads connected to monitor first and then to infant

  2. Leads applied to infant first and then connected to monitor

We recorded the time taken (1) to apply and connect the leads; (2) to display the ECG waveform; (3) to display a HR value and (4) to display HR from the start of the process of acquiring the ECG. For each infant, one of two investigators was chosen by coin toss to acquire the ECG. This investigator then attached the monitor to the infant using the two methods, the order also chosen by coin toss. Data were analysed with SPSS V.20. Median values were compared with independent samples median test.

We studied 30 infants (median (IQR) gestational age 32 (30–39) weeks and birth weight 1760 (1354–3099) g) at a median (IQR) age of 12 (5–21) days. The ECG was applied more quickly when the leads were connected to the monitor before being applied to the infant. Though the time taken to display the ECG waveform was marginally quicker when the leads were applied to the infant before connection to the monitor, there was no statistical difference in the time taken to display a HR value (table 1). Overall, the HR value was displayed more quickly when the leads were connected to the monitor before application to the infant (median (IQR) 26 (21–30) s vs 34 (25–40) s, p=0.001).

We found that connecting the ECG leads to the machine before applying the leads to the infant resulted in quicker HR acquisition in the neonatal unit and propose that this method should be used when acquiring an ECG in newborns in the DR.

Table 1

Time taken to apply the electrodes and to display data for each method of application



  • Contributors CPFO’ participated in study design, protocol development, submission to research ethics committee, designing parent information leaflet and consent form, data collection and entry, and data analysis and interpretation.

  • Competing interests None declared.

  • Ethics approval National Maternity Hospital Research Ethics Committee.

  • Provenance and peer review Not commissioned; internally peer reviewed.