title: Comparison of arterial pressure waveform analysis with the lithium dilution technique to monitor cardiac output in anesthetized dogs.
abstract: OBJECTIVE
  To assess agreement between arterial pressure waveform-derived cardiac output (PCO) and lithium dilution cardiac output (LiDCO) systems in measurements of various levels of cardiac output (CO) induced by changes in anesthetic depth and administration of inotropic drugs in dogs.
  
  
  METHODS
  6 healthy dogs.
  
  
  METHODS
  Dogs were anesthetized on 2 occasions separated by at least 5 days. Inotropic drug administration (dopamine or dobutamine) was randomly assigned in a crossover manner. Following initial calibration of PCO measurements with a LiDCO measurement, 4 randomly assigned treatments were administered to vary CO; subsequently, concurrent pairs of PCO and LiDCO measurements were obtained. Treatments included a light plane of anesthesia, deep plane of anesthesia, continuous infusion of an inotropic drug (rate adjusted to achieve a mean arterial pressure of 65 to 80 mm Hg), and continuous infusion of an inotropic drug (7 microg/kg/min).
  
  
  RESULTS
  Significant differences in PCO and LiDCO measurements were found during deep planes of anesthesia and with dopamine infusions but not during the light plane of anesthesia or with dobutamine infusions. The PCO system provided higher CO measurements than the LiDCO system during deep planes of anesthesia but lower CO measurements during dopamine infusions.
  
  
  CONCLUSIONS
  The PCO system tracked changes in CO in a similar direction as the LiDCO system. The PCO system provided better agreement with LiDCO measurements over time when hemodynamic conditions were similar to those during initial calibration. Recalibration of the PCO system is recommended when hemodynamic conditions or pressure waveforms are altered appreciably.
authors.affiliation: Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada.
authors.forename: Hui Cheng
authors.initials: HC
authors.lastname: Chen
authors.forename: Melissa D
authors.initials: MD
authors.lastname: Sinclair
authors.forename: Doris H
authors.initials: DH
authors.lastname: Dyson
authors.forename: Wayne N
authors.initials: WN
authors.lastname: McDonell
authors.forename: William C
authors.initials: WC
authors.lastname: Sears
mesh_terms: D000768:Anesthesia, General / Q000662:veterinary*; D000818:Animals; D002302:Cardiac Output / Q000502:physiology*; D002316:Cardiotonic Agents / Q000008:administration & dosage; D004280:Dobutamine / Q000008:administration & dosage; D004285:Dogs / Q000502:physiology*; D004298:Dopamine / Q000008:administration & dosage; D007201:Indicator Dilution Techniques / Q000662:veterinary*; D008094:Lithium / Q000008:administration & dosage*
chemical_list: D002316:Cardiotonic Agents; D004280:Dobutamine; D008094:Lithium; D004298:Dopamine