title: Performance of noninvasive partial CO2 rebreathing cardiac output and continuous thermodilution cardiac output in patients undergoing aortic reconstruction surgery.
abstract: BACKGROUND
  In the partial CO(2) rebreathing method, monitored changes in CO(2) elimination and end-tidal CO(2) in response to a brief rebreathing period are used to estimate cardiac output. However, dynamic changes in CO(2) production during ischemia and reperfusion may affect the accuracy of these estimates. This study was designed to compare measurements of cardiac output as produced by the partial CO(2) rebreathing (NICO), bolus (BCO), and continuous thermodilution (CCO) methods of monitoring cardiac output.
  
  
  METHODS
  Cardiac output was continuously monitored using both NICO and CCO in 28 patients undergoing aortic reconstruction. BCO measurements were taken at the following intervals when hemodynamic stability was achieved: (1) after anesthetic induction; (2) during aortic cross-clamp; (3) at reperfusion of the iliac artery; and, (4) during peritoneal closure.
  
  
  RESULTS
  The bias and precision (1 SD) derived from all the measurements between NICO and BCO was -0.58 +/- 0.9 l/min, whereas for CCO and BCO it was 0.38 +/- 1.17 l/min. The bias between NICO and BCO was small after anesthetic induction and during cross-clamp, but increased following reperfusion. The bias between CCO and BCO was relatively small until reperfusion but increased significantly at peritoneal closure.
  
  
  CONCLUSIONS
  Results indicate that in aortic reconstruction surgery the performance of NICO monitoring is comparable with that of CCO; however, the direction of bias in these continuous measurement devices is the opposite.
authors.affiliation: Department of Anesthesiology, Keio University, Tokyo, Japan. ykotake@sc.itc.keio.ac.jp
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Kotake
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Moriyama
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Innami
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Shimizu
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Ueda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Morisaki
authors.forename: Junzo
authors.initials: J
authors.lastname: Takeda
mesh_terms: D000368:Aged; D000758:Anesthesia; D001012:Aorta, Abdominal / Q000601:surgery*; D017544:Aortic Aneurysm, Abdominal / Q000601:surgery; D002245:Carbon Dioxide; D002302:Cardiac Output / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D013815:Thermodilution / Q000379:methods*; D014656:Vascular Surgical Procedures
chemical_list: D002245:Carbon Dioxide