title: Noninvasive assessment of cardiac output in critically ill patients by analysis of the finger blood pressure waveform.
abstract: OBJECTIVE
  To assess whether the measurement of cardiac output by computer-assisted analysis of the finger blood pressure waveform can substitute for the thermodilution method in critically ill patients.
  
  
  METHODS
  Prospective data collection.
  
  
  METHODS
  Emergency department in a 2000-bed inner city hospital
  
  
  METHODS
  Forty-six critically ill patients requiring invasive monitoring for clinical management were prospectively studied.
  
  
  METHODS
  Under local anesthesia a 7-Fr pulmonary artery catheter was inserted via the central subclavian or jugular vein. Cardiac output was determined by the use of a cardiac output computer and injections of 10 mL ice-cold glucose 5%. Noninvasive cardiac output was calculated from the finger blood pressure waveform by the use of the test software program.
  
  
  RESULTS
  Three hundred twenty-three pairs of invasive and noninvasive hemodynamic measurements were collected in intervals of 30 mins from 46 patients (mean age 61.9 +/- 12.4 yrs; 35 male, 11 female). The average cardiac index during the study period was 2.83 L/min/m2 (range 0.97 to 5.56). The overall discrepancy between both measurements was 0.14 L/min/m2 (95% confidence interval: 0.10-.018, p < .001). Seventy-five (23.2%) measurements had an absolute discrepancy > +/- 0.50 L/min/m2. Noninvasive and invasive comparisons of mean differential cardiac output were out of phase for 9.7% of all readings.
  
  
  CONCLUSIONS
  Computer-assisted analysis of finger blood pressure waveform to assess cardiac output is not a substitute for the thermodilution method due to a high percentage (23.2%) of inaccurate readings; however, it may be a useful tool for the detection of relative hemodynamic trends in critically ill patients.
authors.affiliation: Department of Emergency Medicine, University of Vienna, New General Hospital, Austria.
authors.forename: M M
authors.initials: MM
authors.lastname: Hirschl
authors.forename: M
authors.initials: M
authors.lastname: Binder
authors.forename: M
authors.initials: M
authors.lastname: Gwechenberger
authors.forename: H
authors.initials: H
authors.lastname: Herkner
authors.forename: A
authors.initials: A
authors.lastname: Bur
authors.forename: H
authors.initials: H
authors.lastname: Kittler
authors.forename: A N
authors.initials: AN
authors.lastname: Laggner
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure; D001795:Blood Pressure Determination / Q000379:methods; D002302:Cardiac Output; D003199:Computer Systems; D003422:Critical Care; D004636:Emergency Service, Hospital; D005260:Female; D005385:Fingers / Q000098:blood supply / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods*; D011674:Pulse; D012815:Signal Processing, Computer-Assisted; D012984:Software; D013815:Thermodilution