Signal Quality of Electrical Cardiometry and Perfusion Index in Very Preterm Infants

Neonatology. 2021;118(6):672-677. doi: 10.1159/000518061. Epub 2021 Sep 22.


Objective: The use of noninvasive monitoring of neonatal hemodynamics is increasing in neonatal care. Methods include noninvasive cardiac output estimated by electrical cardiometry (EC) and peripheral perfusion as perfusion index (PI) using pulse oximetry. Our aim was to evaluate the feasibility to continuously monitor preterm infants with EC and PI during the first 2 postnatal days and the effects of averaging EC data in signal quality (SigQ) analysis.

Design: Prospective observational study.

Setting: Tertiary neonatal academic hospital.

Patients: Preterm infants <32 weeks gestation from birth until 48 h.

Main outcome measures: Continuous EC and PI measurements. Feasibility was quantified as the time with high SigQ, classified using SigQ index in EC and exception codes in PI. Our predefined threshold for good feasibility was minimum of 24 h with high SigQ for both.

Results: Twenty-two preterm infants (median [IQR] gestational age 28 + 6 (26 + 0, 30 + 4) weeks + days, birth weight 960 [773, 1,500] g) were included. We recorded a minimum of 24 h with high SigQ in 14 infants for EC (unaveraged data) and 22 infants for PI measurements. The median (range) % of recording time with high SigQ was 74% (50%, 88%) for EC and 94% (82%, 96%) for PI. Using 1 minute averaging for EC data resulted in an increase of infants with minimum 24 h of high SigQ to 21 infants.

Conclusions: EC and PI monitoring are feasible in preterm infants within the first 48 h, but SigQ remains problematic for EC. Signal dropout is masked in averaged EC values.

Keywords: Bioimpedance; Cardiac output; Perfusion index; Pulse oximetry; Transition.

Publication types

  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Cardiac Output
  • Humans
  • Infant
  • Infant, Newborn
  • Infant, Premature
  • Infant, Premature, Diseases*
  • Infant, Very Low Birth Weight
  • Perfusion Index*
  • Young Adult