title: Feasibility of bioelectrical impedance spectroscopy measurement before and after thoracentesis.
abstract: BACKGROUND
  Bioelectrical impedance spectroscopy is applied to measure changes in tissue composition. The aim of this study was to evaluate its feasibility in measuring the fluid shift after thoracentesis in patients with pleural effusion.
  
  
  METHODS
  45 participants (21 with pleural effusion and 24 healthy subjects) were included. Bioelectrical impedance was analyzed for "Transthoracic," "Foot to Foot," "Foot to Hand," and "Hand to Hand" vectors in low and high frequency domain before and after thoracentesis. Healthy subjects were measured at a single time point.
  
  
  RESULTS
  The mean volume of removed pleural effusion was 1169 ± 513 mL. The "Foot to Foot," "Hand to Hand," and "Foot to Hand" vector indicated a trend for increased bioelectrical impedance after thoracentesis. Values for the low frequency domain in the "Transthoracic" vector increased significantly (P < 0.001). A moderate correlation was observed between the amount of removed fluid and impedance change in the low frequency domain using the "Foot to Hand" vector (r = -0.7).
  
  
  CONCLUSIONS
  Bioelectrical impedance changes in correlation with the thoracic fluid level. It was feasible to monitor significant fluid shifts and loss after thoracentesis in the "Transthoracic" vector by means of bioelectrical impedance spectroscopy. The trial is registered with Registration Numbers IRB EK206/11 and NCT01778270.
authors: Department of Cardiology, Pneumology, Angiology and Intensive Care Medicine, University Hospital, RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany.
authors: Matthias Daniel
authors: 0000-0002-3889-5386
authors: MD
authors: Zink
authors: Philips Chair for Medical Information Technology, RWTH Aachen University, Schinkelstraße 2, 52062 Aachen, Germany.
authors: Sören
authors: S
authors: Weyer
authors: Department of Cardiology, Pneumology, Angiology and Intensive Care Medicine, University Hospital, RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany.
authors: Karolin
authors: K
authors: Pauly
authors: Department of Cardiology, Pneumology, Angiology and Intensive Care Medicine, University Hospital, RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany.
authors: Andreas
authors: A
authors: Napp
authors: Department of Cardiology, Pneumology, Angiology and Intensive Care Medicine, University Hospital, RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany.
authors: Michael
authors: M
authors: Dreher
authors: Philips Chair for Medical Information Technology, RWTH Aachen University, Schinkelstraße 2, 52062 Aachen, Germany.
authors: Steffen
authors: S
authors: Leonhardt
authors: Department of Cardiology, Pneumology, Angiology and Intensive Care Medicine, University Hospital, RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany.
authors: Nikolaus
authors: N
authors: Marx
authors: Department of Cardiology, Pneumology, Angiology and Intensive Care Medicine, University Hospital, RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany.
authors: Patrick
authors: P
authors: Schauerte
authors: Department of Cardiology, Pneumology, Angiology and Intensive Care Medicine, University Hospital, RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany.
authors: Karl
authors: K
authors: Mischke
mesh_terms: D000328:Adult; D000368:Aged; D001823:Body Composition / Q000502:physiology*; D001826:Body Fluids / Q000502:physiology*; D016022:Case-Control Studies; D017097:Electric Impedance; D005260:Female; D005528:Foot / Q000502:physiology*; D006225:Hand / Q000502:physiology*; D006801:Humans; D008297:Male; D010996:Pleural Effusion / Q000503:physiopathology*; D013057:Spectrum Analysis / Q000379:methods; D000069258:Thoracentesis / Q000379:methods