Thoracic electrical bioimpedance versus suprasternal Doppler in emergency care

OBJECTIVE: There are a number of cardiac output (CO) monitors that could potentially be used in the ED. Two of the most promising methods, thoracic electrical bioimpedance and suprasternal Doppler, have not been directly compared. The aim of this study was to investigate the feasibility of CO monitoring using suprasternal Doppler and bioimpedance in emergency care and compare haemodynamic data obtained from both monitors. METHODS: Haemodynamic measurements were made on the same group of patients using bioimpedance (Niccomo, Medis, Germany) and suprasternal Doppler (USCOM, Sydney, Australia). RESULTS: Usable CO data were obtained in 97% of patients by suprasternal Doppler and 87% by bioimpedance. The median CO obtained by Doppler was 3.4 L/min lower than bioimpedance. The stroke volume median was lower by 51 mL in Doppler. CONCLUSIONS: These two methods of non-invasive cardiac monitoring are not interchangeable. The results suggest that the choice of non-invasive cardiac monitor is important, but the grounds on which to make this choice are not currently clear.