title: Evaluation of the accuracy and response time of STAT-mode continuous cardiac output.
abstract: OBJECTIVE
  This study was conducted to compare continuous cardiac output (CCO) with bolus thermodilution cardiac output (BTD) at steady state, and to compare the response time of STAT CCO with that of trend CCO, mean arterial pressure, and mixed venous oxygen saturation [SvO2] during an acute hemodynamic change.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  University hospital.
  
  
  METHODS
  Twenty-nine patients undergoing cardiac surgery or liver transplantation.
  
  
  METHODS
  STAT and trend CCO were compared with BTD cardiac output during steady state intraoperatively and postoperatively in the intensive care unit. Ten patients, who required epicardial pacing after cardiac surgery, were studied to compare the response time of STAT CCO with that of trend CCO, mean arterial pressure, and BvO2 after a 10% to 20% increase in pacing rate.
  
  
  RESULTS
  A total of 108 cardiac output data sets were analyzed at steady state. Steady state was defined as stable heart rate and mean arterial pressure (+/- 5%) and stable central venous pressure (+/- 2 mmHg) measured immediately before and after each data set. Cardiac output ranged from 2.3 to 8.5 L/min. The correlation between STAT CCO and BTD was r = 0.94, and for trend CCO and BTD was r = 0.94. The bies and precision for STAT CCO versus BTD were 0.06 L/min (Cl 95%: -0.08 to 0.18) and 0.61 L/min. The bias and precision for trend CCO versus BTD were 0.06 L/min (Cl 95%: -0.04 to 0.16) and 0.49 L/min. Eleven data sets were analyzed to study response time of STAT CCO, which was defined as the first time the percent change of the mean of each variable was significantly increased from baseline. Significant increases in mean arterial pressure and SvO2 were detected after 30 seconds (2.5%, p = 0.01) and 90 seconds (2.0%, p = 0.04), respectively. A significant increase in STAT CCO was reached at 270 seconds (4.4%, p = 0.005). Trend CCO tended to increase but did not reach statistical significance within 6 minutes.
  
  
  CONCLUSIONS
  STAT and trend CCO are accurate and precise and show close agreement with BTD cardiac output at steady state. The faster algorithm of STAT CCO offers some advantage over trend CCO during an acute hemodynamic change. However, because of the averaging process for determining CCO, the response time of STAT CCO is slower than that of mean arterial pressure and SvO2.
authors.affiliation: Department of Anesthesia and Critical Care, Beth Isreal Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Lazor
authors.forename: E T
authors.initials: ET
authors.lastname: Pierce
authors.forename: G D
authors.initials: GD
authors.lastname: Stanley
authors.forename: J L
authors.initials: JL
authors.lastname: Cass
authors.forename: E F
authors.initials: EF
authors.lastname: Halpern
authors.forename: R H
authors.initials: RH
authors.lastname: Bode
mesh_terms: D000465:Algorithms; D015982:Bias; D001794:Blood Pressure; D002302:Cardiac Output; D002304:Cardiac Pacing, Artificial; D006348:Cardiac Surgical Procedures; D002407:Catheterization, Swan-Ganz; D002496:Central Venous Pressure; D003422:Critical Care; D005069:Evaluation Studies as Topic; D006439:Hemodynamics; D006801:Humans; D016014:Linear Models; D016031:Liver Transplantation; D016343:Monitoring, Intraoperative / Q000379:methods*; D010100:Oxygen / Q000097:blood; D011446:Prospective Studies; D013815:Thermodilution / Q000379:methods; D014680:Veins
chemical_list: D010100:Oxygen