title: Pulse oximetry measures a lower heart rate at birth compared with electrocardiography.
abstract: OBJECTIVE
  To examine the effect of time after birth on heart rate (HR) measured by pulse oximetry (PO) (HRPO) and electrocardiography (ECG) (HRECG).
  
  
  METHODS
  HRECG and HRPO (collected at maximum sensitivity) were assessed in 53 term and preterm infants at birth. ECG electrodes and a PO sensor were attached as soon as possible and HRECG and HRPO were compared every 30 seconds from 1-10 minutes after birth. Data were compared using a Wilkinson signed-rank test. Clinical relevance (eg, HR <100 beats per minute [bpm] was tested using a McNemar test).
  
  
  RESULTS
  Seven hundred fifty-five data pairs were analyzed. Median (IQR) gestational age was 37 (31-39) weeks. Mean (SD) starting time of PO and ECG data collection was 99 (33) vs 82 (26) seconds after birth (P = .001). In the first 2 minutes after birth, HRPO was significantly lower compared with HRECG (94 (67-144) vs 150 (91-153) bpm at 60 seconds (P < .05), 81 (60-109) vs 148 (83-170) bpm at 90 seconds (P < .001) and 83 (67-145) vs 158 (119-176) at 120 seconds (P < .001). A HR <100 bpm was more frequently observed with a PO than ECG in the first 2 minutes (64% vs 27% at 60 seconds (P = .05), 56% vs 26% at 90 seconds (P < .05) and 53% vs 21% at 120 seconds (P < .05). HR by ECG was verified by ultrasound for outflow from a subset of infants.
  
  
  CONCLUSIONS
  In infants at birth, HRPO is significantly lower compared with ECG with clinically important differences in the first minutes.
authors.affiliation: Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands. Electronic address: J.J.van_Vonderen@lumc.nl.
authors.forename: Jeroen J
authors.initials: JJ
authors.lastname: van Vonderen
authors.affiliation: The Ritchie Center, Monash Institute for Medical Research, Monash University, Melbourne, Australia.
authors.forename: Stuart B
authors.initials: SB
authors.lastname: Hooper
authors.affiliation: Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Jacco K
authors.initials: JK
authors.lastname: Kroese
authors.affiliation: Division of Pediatric Cardiology, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Arno A W
authors.initials: AA
authors.lastname: Roest
authors.affiliation: Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Ilona C
authors.initials: IC
authors.lastname: Narayen
authors.affiliation: Department of Medical Statistics and Bioinformatics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Erik W
authors.initials: EW
authors.lastname: van Zwet
authors.affiliation: Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Arjan B
authors.initials: AB
authors.lastname: te Pas
mesh_terms: D001919:Bradycardia / Q000503:physiopathology*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D009426:Netherlands; D010092:Oximetry / Q000379:methods*; D011446:Prospective Studies; D013997:Time Factors