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Thoracic electrical bioimpedance: a tool to determine cardiac versus non-cardiac causes of acute dyspnoea in the emergency department
  1. Christiane Vorwerk,
  2. Hanusha Jeyanithi,
  3. Timothy J Coats
  1. Academic Unit of Emergency Medicine, University of Leicester, Leicester, UK
  1. Correspondence to Dr Christiane Vorwerk, Emergency Department, Leicester Royal Infirmary, Leicester LE1 5WW, UK; cv28{at}


Objectives To determine whether cardiohaemodynamic parameters, using non-invasive thoracic electrical bioimpedance (TEB), can differentiate between cardiac and non-cardiac causes of acute breathlessness in adult emergency department (ED) patients.

Methods A prospective cohort study of adult patients who presented with acute breathlessness to the ED of a large urban teaching hospital. Study patients had their cardiohaemodynamic parameters measured, using a TEB device. The patient’s hospital discharge diagnosis was used as the definitive diagnosis to determine whether the underlying cause of acute dyspnoea was cardiac or non-cardiac related. The definitive diagnosis was compared with the TEB data and the ED physician’s diagnosis.

Results 52 patients were recruited into the study, of whom 51 had complete TEB data and were included in the analysis. There were statistically significant differences in cardiac output (6.2 vs 7.9, p<0.001), cardiac index (CI; 3.1 vs 4.4, p<0.001), systemic vascular resistance (1227 vs 933, p=0.002) and systemic vascular resistance index (2403 vs 1681, p<0.001) between the cardiac and non-cardiac cohort. CI was found to be an excellent discriminator (receiver operating characteristics area under the curve 0.906). The optimal diagnostic criterion for CI to distinguish between cardiac and non-cardiac dyspnoea was 3.2 l/min per square metre or less (positive likelihood ratio 7.9; negative likelihood ratio 0.14).

Conclusion This study demonstrated that non-invasive TEB cardiohaemodynamic parameters can differentiate between cardiac and non-cardiac-related causes of dyspnoea in ED patients presenting with acute breathlessness. A large-scale trial is required to determine if TEB-derived cardiohaemodynamic information can aid ED clinicians in their early clinical decision-making and improve the care and outcome of patients with dyspnoea.

  • cardiac output
  • clinical assessment
  • dyspnoea
  • heart failure
  • emergency department management
  • impedance cardiography
  • systemic vascular resistance
  • thoracic electrical bioimpedance

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  • Competing interests None.

  • Patient consent Obtained.

  • Ethics approval The study was approved by the LNR Research Ethics Committee (REC ref 07/H0406/244) on 15 November 2007 and the UHL NHS Trust R&D Department on 26 November 2007.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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