title: Comparison of stroke volume measurement between non-invasive bioreactance and esophageal Doppler in patients undergoing major abdominal-pelvic surgery.
abstract: OBJECTIVE
  Bioreactance is a non-invasive technology for measuring stroke volume (SV) in the operating room and critical care setting. We evaluated how the NICOM®bioreactance device performed against the CardioQ®esophageal Doppler monitor in patients undergoing major abdominal-pelvic surgery, focusing on the effect of different hemodynamic interventions.
  
  
  METHODS
  SVNICOMand SVODMwere simultaneously measured intraoperatively, including before and after interventions including fluid challenge, vasopressor boluses, peritoneal gas insufflation/removal, and Trendelenburg/reverse Trendelenburg patient positioning.
  
  
  RESULTS
  A total of 768 values were collected from 21 patients. Pre- and post-intervention measures were recorded on 155 occasions. Bland-Altman analysis revealed a bias of 8.6 ml and poor precision with wide limits of agreement (54 and -37 ml) and a percentage error of 50.6%. No improvement in precision was detected after taking into account repeated measurements for each patient (bias: 8 ml; limits of agreement: 74 and -59 ml). Concordance between changes in SVNICOMand SVODMbefore and after interventions was also poor: 78.7% (all measures), 82.4% (after vasopressor administration), and 74.3% (after fluid challenge). Using Doppler SV as the reference technique, the area under the receiver operating characteristic curve assessing the ability of the NICOM device to predict fluid responsiveness was 0.81 (0.7-0.9).
  
  
  CONCLUSIONS
  In patients undergoing major abdomino-pelvic surgery, SV values obtained by NICOM showed neither clinically or statistically acceptable agreement with those obtained by esophageal Doppler. Although, in the setting of this study, bioreactance technology cannot reliably replace esophageal Doppler monitoring, its accuracy for predicting fluid responsiveness was higher, up to approximately 80%.
  
  
  BACKGROUND
  Observational study.
authors.affiliation: Division of Medicine, Bloomsbury Institute of Intensive Care Medicine, University College London, Gower St, London, WC1E 6BT, UK. gennaro.depascalemd@gmail.com.|Division of Anaesthesia, University College Hospital, 235 Euston Road, London, NW1 2BU, UK. gennaro.depascalemd@gmail.com.|Policlinico Universitario A. Gemelli Università Cattolica del Sacro Cuore, Largo A. Gemelli, 8, 00168, Rome, Italy. gennaro.depascalemd@gmail.com.
authors.forename: Gennaro
authors.initials: G
authors.lastname: De Pascale
authors.affiliation: Division of Medicine, Bloomsbury Institute of Intensive Care Medicine, University College London, Gower St, London, WC1E 6BT, UK.|Division of Anaesthesia, University College Hospital, 235 Euston Road, London, NW1 2BU, UK.
authors.forename: Mervyn
authors.initials: M
authors.lastname: Singer
authors.affiliation: Division of Medicine, Bloomsbury Institute of Intensive Care Medicine, University College London, Gower St, London, WC1E 6BT, UK.|Division of Anaesthesia, University College Hospital, 235 Euston Road, London, NW1 2BU, UK.
authors.forename: David
authors.initials: D
authors.lastname: Brealey
mesh_terms: D000005:Abdomen / Q000601:surgery; D000368:Aged; D003422:Critical Care; D015150:Echocardiography, Doppler / Q000379:methods*; D004947:Esophagus / Q000000981:diagnostic imaging*; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods*; D012372:ROC Curve; D013318:Stroke Volume
keywords: Bioreactance technology; Esophageal Doppler; Hemodynamic monitoring