Non-Invasive Cardiac Output Monitoring in Neonates

Background: Cardiovascular monitoring is an integral component in the care of both term and preterm infants. Current practises rely mainly on heart rate and blood pressure measurements, as more invasive methods are neither applicable or feasible in this particular group of patients. Bedside echocardiography gives valuable information about the cardiac status of an infant but only depicts a single point in time. Non-invasive cardiac output monitoring(NiCO) has the potential to provide continuous real time measurements of certain parameters, primarily cardiac output(CO). The two most recent models for estimating CO non-invasively are Electrical Cardiometry (EC) and Bioreactance (BR).

Objectives: To summarise the use of NiCO in neonatal care, focusing on the technical and practical aspects, as well as evidence on accuracy, feasibility and confounders. We discuss the various scenarios in which NiCO has been used to date and identify potential areas for future research.

Methods: A review of the available literature was carried out to identify studies using NiCO in neonatal populations.

Results: A range of studies using EC or BR were identified, compromising over 2000 mostly preterm infants. Thirteen studies looked at the accuracy of NiCO but the vast majority of these address accuracy as the interchangeability with Echo as the reference method. Studies to date using EC/BR suggest that they cannot substitute Echo, but that they may offer some benefit in trend monitoring. Feasibility remains a concern and many studies have reported problems with the size of the adhesive sensors particularly those using bioreactance. Factors such as PDAs, respiratory support and level of cardiac output have all been shown to significantly affect the bias to the reference method.

Conclusion: The use of NiCO remains limited to the research setting. Further studies looking at its accuracy and confounders needs to be addressed before implementation in routine clinical care.