Noninvasive cardiac monitoring in pregnancy: impedance cardiography versus echocardiography

Abstract

Objectives The objective of this study was to report thoracic impedance cardiography (ICG) measurements and compare them to echocardiography (echo) measurements throughout pregnancy and in varied maternal positions. Methods A prospective cohort study involving 28 healthy parturients was performed using ICG and echo at three time points and in two maternal positions. Pearson correlations, Bland-Altman plots and paired t-tests were used for statistical analysis. Results Significant agreements between many but not all ICG and echo contractility, flow and resistance measurements were demonstrated. Differences in stroke volume due to maternal position were also detected by ICG in the antepartum period. Significant trends were observed by ICG for cardiac output and thoracic fluid content (TFC) (p < 0.025) with advancing pregnancy stages. Conclusions ICG and echo demonstrate significant correlations in some but not all measurements of cardiac function. ICG has the ability to detect small changes in SV associated with maternal position change. ICG measurements reflected maximal cardiac contractility in the antepartum period yet reflected a decrease in contractility and an increase in TFC in the postpartum period.

Maternal functional hemodynamics in uncomplicated twin pregnancies: A longitudinal study using impedance cardiography

“…ICG has been proposed as an alternative device for the assessment of cardiovascular function because it is quick, user‐friendly, operator‐independent, requires minimal training to use and is suitable for bedside functional hemodynamic monitoring . Although its use has been controversial and it is not interchangeable with echocardiography, Burlingame et al demonstrated a significant correlation between ICG and echocardiography during pregnancy. In addition, modest agreement and significant correlation with echocardiography in measuring SV and CO variation after PLR have been demonstrated in singleton pregnancies .…”

“…Moreover, the study cohort did not consist of a homogeneous ethnic population. The accuracy of measuring hemodynamics using ICG has been questioned, but this technique has been validated in pregnant populations and significantly correlates with echocardiography, also during PLR . Moreover, a new generation of ICG devices and recent updates in the ICG signal analysis software have improved ICG measurement accuracy .…”

“…Impedance cardiography (ICG) has been proposed to assess cardiac function due to its advantages including noninvasiveness, cost‐effectiveness, ease of use, possibility to assess hemodynamic changes by repeated and continuous measurements, and long‐term monitoring capability . Although its accuracy has been questioned, ICG has been validated in pregnant populations with modest agreement with echocardiography . Moreover, a new generation of devices together with recent updates in ICG signal analysis software have improved its measurement accuracy .…”

Methods and considerations concerning cardiac output measurement in pregnant women: recommendations of the International Working Group on Maternal Hemodynamics

“…Given its accessibility and ease of use, impedance cardiography at one time became very attractive for the measurement of CO in both pregnant and non‐pregnant women. Nevertheless, most validation studies, in both non‐pregnant and pregnant women, using any of the available devices, have not been able to show sufficient accuracy and precision as compared with reference methods such as PAC or TTE in reflecting absolute CO values. As such, at the moment, all these devices (Table ) are probably not suited to showing ‘true CO’ values.…”

Diagnosis of mitral insufficiency using impedance cardiography technique ICG

“…Moreover, it has been used to detect ischemia [12]. Furthermore, it may be useful to examine the effect of different diseases of the autonomic nervous system like the Parkinson's disease [13,14], for monitoring pregnant women [15,16], for diagnosis and treatment of patients with hypertension [17,18]. Likewise, it has been used to monitor surgical operations [19,20] and dialyzed patients [21,22].…”