title: A new non-invasive continuous cardiac output trend solely utilizing routine cardiovascular monitors.
abstract: OBJECTIVE
  Three of the us developed a new non-invasive continuous cardiac output (CCO) measurement method utilizing routine clinical monitors based on the pulse-contour analysis combined with pulse wave transit time (PWTT). Using pulmonary artery catheter (CCOpa), we compared this estimated CCO (esCO) with the thermodilution CCO early after cardiac surgery, and tested whether the esCO method has potential of being an alternative measure of CCO.
  
  
  METHODS
  Thirty-six patients without continued arrhythmias were studied. esCO was computed using electrocardiogram (ECG) monitor, arterial pressure monitor and pulse-oximetry system. Both sets of data (esCO and CCOpa), by averaging the results of the preceding 10 min, were compared at 30-min intervals throughout the 15.8 +/- 3.3 h (S.D.) of study. Bland-Altman plots and correlation analysis were used for statistical comparison.
  
  
  RESULTS
  A total of 981 paired sets of data (89.9%) among 1093 measurements were compared in the absence of displacement of either pulse-oximetry or ECG probes and/or inaccurate detection of R wave. The difference between esCO and CCOpa results was -0.06 +/- 0.82 L/min (S.D.), and there was a linear correlation between them (r = 0.80, p < 0.0001). The difference between them was 0.00 +/- 0.48 L/min at the first 1 h, which remained unchanged throughout 20 h after the start of measurement.
  
  
  CONCLUSIONS
  The results demonstrate that esCO has a close correlation with the CCOpa, even though the two methods are not interchangeable. The results suggest that esCO method has potential of being an alternative non-invasive cardiac output trend, unless there are apparent arrhythmias.
authors.affiliation: Department of Anesthesiology, University of Hirosaki School of Medicine, Hirosaki, Japan. ishihara@cc.hirosaki-u.ac.jp
authors.forename: Hironori
authors.initials: H
authors.lastname: Ishihara
authors.forename: Hirobumi
authors.initials: H
authors.lastname: Okawa
authors.forename: Ken
authors.initials: K
authors.lastname: Tanabe
authors.forename: Toshihito
authors.initials: T
authors.lastname: Tsubo
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Sugo
authors.forename: Takeshi
authors.initials: T
authors.lastname: Akiyama
authors.forename: Sunao
authors.initials: S
authors.lastname: Takeda
mesh_terms: D000328:Adult; D000368:Aged; D001145:Arrhythmias, Cardiac; D002302:Cardiac Output; D013504:Cardiovascular Surgical Procedures; D002407:Catheterization, Swan-Ganz; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods; D011674:Pulse; D012680:Sensitivity and Specificity; D013815:Thermodilution