Cardiothoracic variables measured by bioelectrical impedance in preterm and term neonates

Area of Science:

• Neonatal physiology
• Cardiovascular monitoring
• Medical device technology

Background:

• Establishing normal physiological parameters is essential for accurate diagnosis and treatment in neonatal intensive care.
• Impedance cardiography offers a non-invasive method for assessing hemodynamic function.

Purpose of the Study:

• To determine reference ranges for impedance-derived cardiac output, stroke volume, and transthoracic impedance in healthy preterm and term neonates.
• To provide baseline data for critically ill neonates within the intensive care nursery weight range.

Main Methods:

• A prospective, case-referent study was conducted in a university medical center's special care and term nurseries.
• Impedance cardiac output, stroke volume, and baseline transthoracic impedance were measured in 27 preterm and 25 term newborns without cardiovascular issues.

Main Results:

• Stroke volume indexed to body weight was 1.4 ± 0.5 mL/kg in preterm and 1.6 ± 0.7 mL/kg in term neonates.
• Cardiac output indexed to body weight was 214 ± 68 mL/min/kg in preterm and 205 ± 78 mL/min/kg in term neonates.
• Both cardiac output and stroke volume correlated positively with body weight, while transthoracic impedance correlated negatively and curvilinearly with body weight.

Conclusions:

• This study reports the first reference values for transthoracic impedance and related measures using a standard electrode lead configuration in neonates.
• The established values provide a valuable resource for non-invasive hemodynamic assessment in neonatal intensive care.