Heart Rate Assessment Technologies for Neonatal Resuscitation

• Author / Creator

  Johnson, Peter A.

• Every year, 13-26 million newborn infants require immediate respiratory support and 1-2 million require extensive resuscitation involving critical interventions, such as chest compressions and epinephrine administration. For these infants, heart rate (HR) is the most sensitive indicator to guide interventions during neonatal resuscitation. An inaccurate or slow HR assessment could lead to inappropriate, prolonged, or delayed interventions, increasing the risk of serious hypoxic injury and death. International neonatal resuscitation guidelines currently recommend umbilical cord palpation, auscultation with a stethoscope, electrocardiography (ECG), and pulse oximetry for HR assessment. However, auscultation and palpation tend to underestimate HR, while ECG and pulse oximetry are suboptimal for initial HR assessment and in special cases. This thesis reviewed novel technologies for HR assessment including digital stethoscope (DS), tap-based mobile apps, Doppler ultrasound, photoplethysmography, camera-based photoplethysmography (cPPG), laser Doppler vibrometry, ECG-based techniques, and sensor-based technologies. While several are promising, limited evidence exists for the use of these technologies during neonatal resuscitation. The objective of this thesis was to evaluate the use of the DS using three auscultation techniques including the recommended 6-sec method (DS+6sec), 10-sec method (DS+10sec), and NeoTapLS app (DS+NeoTapLS), Doppler ultrasound, and cPPG, for neonatal resuscitation.

   An animal and clinical study were conducted. In the animal study, piglets (n=20, 1-3 days) were anesthetised, surgically instrumented, mechanically ventilated, and subjected to hypoxia followed by asphyxia. Asphyxia was induced by clamping the endotracheal tube and disconnecting the ventilator, until asystole was confirmed by zero carotid blood flow (CBF). During asphyxia, HR assessments were performed using DS+6sec, DS+10sec, DS+NeoTapLS, and Doppler ultrasound. These were compared to gold standards, CBF-derived HR and ECG HR. Bland-Altman analysis, intra-class correlation coefficients (ICC), and frequency of errors according to HR decision-making ranges, were used as measures of accuracy. Assessment times for DS+6sec, DS+10sec, and DS+NeoTapLS were also measured. No differences in mean HR were observed when compared to ECG and CBF HR. Bland-Altman analysis revealed mean differences (95% limits of agreement) of -1 (-21 to +19), 0.6 (-23 to +25), 0.7 (-13 to +15), and 0.9 (-13 to +15) bpm, for DS+6sec, DS+10sec, DS+NeoTapLS, and Doppler ultrasound, respectively. An adjusted ICC of 0.935, 0.905, 0.966, and 0.969 was also computed for DS+6sec, DS+10sec, DS+NeoTapLS, and Doppler ultrasound, respectively. The overall proportion of errors was 4% using DS+6sec, DS+10sec, and DS+NeoTapLS, and 9% using Doppler ultrasound. Of the DS auscultation techniques, using NeoTapLS had the shortest assessment time 3(2–4) sec. Surrounding noises could influence the accuracy of DS HR and the use of the 10-sec method placed a greater cognitive workload on the assessor. The accuracy of Doppler ultrasound could also be affected by motion artefacts, ventilation peaks, and low cardiac output.
  
   In the clinical study, early gestational newborn infants (n=40, <37 weeks) requiring respiratory support were recruited from the delivery room. A video camera was installed prior to delivery and used to collect HR recordings for cPPG. ECG was utilized as per local resuscitation procedures and HR was stored for analysis. Bland-Altman analysis and ICC was utilized to measure the accuracy of cPPG HR using ECG HR as the gold standard. Bland-Altman analysis revealed a mean difference (95% limits of agreements) of +0.4 (- 8.0 to +8.7) bpm between measured mean cPPG HR and ECG HR with an ICC of 0.83. Motion artefacts, ambient light, and low perfusion levels could influence the accuracy of cPPG assessments.
  
   These use of DS+6sec, DS+10sec, DS+NeoTapLS, Doppler ultrasound, and cPPG were all accurate for HR assessment. The use of DS+6sec, DS+NeoTapLS, and Doppler ultrasound, might improve initial HR assessment at birth. DS+6sec, DS+NeoTapLS, Doppler ultrasound, and cPPG have a similar accuracy to ECG and are also promising alternatives for continuous HR assessment. However, further clinical trials and studies are necessary to test if the use of these technologies ultimately enhance neonatal resuscitation and improve outcomes at birth.
  

• Subjects / Keywords

  • birth asphyxia
  • camera-based photoplethysmography
  • technology
  • heart rate
  • Doppler ultrasound
  • cardiopulmonary resuscitation
  • digital stethoscope
  • mobile app
  • delivery room
  • neonatal resuscitation

• Graduation date

  Fall 2020

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-sjqk-cc04

• License

  Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.