Thoracic electrical bioimpedance: a tool to determine cardiac versus non-cardiac causes of acute dyspnoea in the emergency department

Emerg Med J. 2010 May;27(5):359-63. doi: 10.1136/emj.2009.073437.

Abstract

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.

Publication types

  • Evaluation Study

MeSH terms

  • Adult
  • Aged
  • Area Under Curve
  • Cardiac Output / physiology
  • Diagnosis, Differential
  • Dyspnea / etiology*
  • Electric Impedance*
  • Emergency Service, Hospital*
  • Female
  • Heart Diseases / complications*
  • Heart Diseases / diagnosis
  • Heart Diseases / physiopathology
  • Humans
  • Male
  • Middle Aged
  • Monitoring, Physiologic / instrumentation
  • Monitoring, Physiologic / methods*
  • Prospective Studies
  • Resuscitation / methods
  • Vascular Resistance / physiology