title: Radial Artery Applanation Tonometry for Continuous Noninvasive Cardiac Output Measurement: A Comparison With Intermittent Pulmonary Artery Thermodilution in Patients After Cardiothoracic Surgery.
abstract: OBJECTIVE
  Radial artery applanation tonometry allows completely noninvasive continuous cardiac output estimation. The aim of the present study was to compare cardiac output measurements obtained with applanation tonometry (AT-CO) using the T-Line system (Tensys Medical, San Diego, CA) with cardiac output measured by intermittent pulmonary artery thermodilution using a pulmonary artery catheter (PAC-CO) with regard to accuracy, precision of agreement, and trending ability.
  
  
  METHODS
  A prospective method comparison study.
  
  
  METHODS
  The study was conducted in a cardiosurgical ICU of a German university hospital.
  
  
  METHODS
  We performed cardiac output measurements in 50 patients after cardiothoracic surgery.
  
  
  METHODS
  None.
  
  
  RESULTS
  Three independent sets of three consecutive thermodilution measurements (i.e., PAC-CO) each were performed per patient, and AT-CO was measured simultaneously. The average of the three thermodilution cardiac output measurements was compared with the average of the corresponding three AT-CO values resulting in 150 paired cardiac output measurements. In 13 patients, cardiac output-modifying maneuvers performed for clinical reasons additionally allowed to evaluate trending ability. For statistical analysis, we used Bland-Altman analysis, the percentage error, four-quadrant plot, and concordance analysis. Mean PAC-CO was 4.7 ± 1.2 L/min and mean AT-CO was 4.9 ± 1.1 L/min. The mean of differences was -0.2 L/min with 95% limits of agreement of -1.8 to + 1.4 L/min. The percentage error was 34%. The concordance rate was 95%.
  
  
  CONCLUSIONS
  Continuous cardiac output measurement using the noninvasive applanation tonometry technology is basically feasible in ICU patients after cardiothoracic surgery. The applanation tonometry technology provides cardiac output values with reasonable accuracy and precision of agreement compared with intermittent pulmonary artery thermodilution measurements in a clinical study setting and is able to reliably track cardiac output changes induced by cardiac output-modifying maneuvers.
authors.affiliation: 1Department of Anesthesiology, Center of Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. 2Department of Medical Biometry and Epidemiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. 3Department of Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. 4Department of Cardiovascular Surgery, University Heart Center Hamburg, Hamburg, Germany.
authors.forename: Julia Y
authors.initials: JY
authors.lastname: Wagner
authors.forename: Harun
authors.initials: H
authors.lastname: Sarwari
authors.forename: Gerhard
authors.initials: G
authors.lastname: Schön
authors.forename: Mathias
authors.initials: M
authors.lastname: Kubik
authors.forename: Stefan
authors.initials: S
authors.lastname: Kluge
authors.forename: Hermann
authors.initials: H
authors.lastname: Reichenspurner
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Reuter
authors.forename: Bernd
authors.initials: B
authors.lastname: Saugel
mesh_terms: D000368:Aged; D002302:Cardiac Output; D006348:Cardiac Surgical Procedures; D005260:Female; D006334:Heart Function Tests / Q000379:methods; D006801:Humans; D008297:Male; D008365:Manometry; D011182:Postoperative Care / Q000379:methods*; D011446:Prospective Studies; D011651:Pulmonary Artery; D017534:Radial Artery / Q000502:physiology*; D015203:Reproducibility of Results; D013815:Thermodilution