title: Lithium dilution cardiac output measurement: a comparison with thermodilution.
abstract: OBJECTIVE
  To compare the results of cardiac output measurements obtained by lithium dilution and thermodilution.
  
  
  METHODS
  Case series, observational study.
  
  
  METHODS
  High-dependency postoperative unit and intensive care unit of a teaching hospital.
  
  
  METHODS
  Forty patients were studied. Thirty-four patients had undergoing heart surgery requiring cardiopulmonary bypass within the previous 2 days; the diagnoses in the other patients were myocardial infarct (n = 2), septicemia (n = 2), adult respiratory distress syndrome, and pericardectomy.
  
  
  METHODS
  Cardiac output was measured five times in each patient, using lithium dilution (single measurement) and bolus thermodilution (series of three to six measurements according to standard clinical practice, taking the average of the closest three). In a subgroup of 14 patients, cardiac output was also measured using "continuous thermodilution."
  
  
  RESULTS
  Comparing lithium dilution with bolus thermodilution, the mean of the differences (lithium dilution-thermodilution) was -0.25 +/- 0.46 [SD] L/min. Linear regression analysis gave y = 0.31 + 0.89x (r2 = .94) for lithium dilution vs. thermodilution.
  
  
  CONCLUSIONS
  The overall agreement between the two methods was good. The variability of the thermodilution measurements was greater than that of the lithium dilution measurements. The lithium dilution method is at least as accurate as bolus thermodilution and, since pulmonary artery catheterization is not needed, it has the advantages of being safe and quick to perform.
authors.affiliation: Rayne Institute, St. Thomas' Hospital, London, UK.
authors.forename: R
authors.initials: R
authors.lastname: Linton
authors.forename: D
authors.initials: D
authors.lastname: Band
authors.forename: T
authors.initials: T
authors.lastname: O'Brien
authors.forename: M
authors.initials: M
authors.lastname: Jonas
authors.forename: R
authors.initials: R
authors.lastname: Leach
mesh_terms: D000328:Adult; D000368:Aged; D002302:Cardiac Output; D001026:Coronary Artery Bypass; D003422:Critical Care / Q000379:methods*; D006801:Humans; D007201:Indicator Dilution Techniques / Q000295:instrumentation; D008094:Lithium; D008875:Middle Aged; D011184:Postoperative Period; D013815:Thermodilution
chemical_list: D008094:Lithium