title: Assessment of cardiac output and volume load by transpulmonary thermodilution technique in immature pigs.
abstract: OBJECTIVE
  To assess the accuracy of cardiac output (CO) measured by transpulmonary thermodilution technique (TPTD)and explore the validity of intrathoracic blood volume index (ITBVI) for assessment of circulatory volume status.
  
  
  METHODS
  Ten immature pigs with a mean weight of (20.6±1.9)kg were studied during the conditions including normovolemia, hypervolemia, and hypovolemia. Simultaneous CO was measured in each condition using pulmonary artery thermodilution (PATD) method and TPTD. More specifically, CO (COPA) was determined with PATD, while CO (COTP) and ITBVI were determined with TPTD. All measurements were repeated 3 times. Central venous pressure (CVP) and heart rate were measured at the same time. The potential correlations of CVP and ITBVI with cardiac index (CI) and stroke volume index (SVI) in each blood volume status were analyzed.
  
  
  RESULTS
  A total of 90 simultaneous measurements of COPA and COTP in 3 different blood volume conditions were made. The correlation coefficient between the two measurements was 0.977 (P<0.001) and the mean difference was (0.25±0.26)L/min (95%CI:0.20-0.30 L/min, P<0.001). The coefficient of variation of COTP was 3.7%, while COPA was 5.4%. Compared with those in normovolemia, CVP and ITBVI in hypervolemia significantly increased (P=0.002, 0.019), ITBVI in hypovolemia decreased significantly (P<0.001), and CVP in hypovolemia decreased insignificantly (P=0.05). Correlation analysis revealed a significant correlation between ITBVI with CI and SVI in normovolemia (r=0.741, P=0.014; r=0.885, P=0.001). In contrast, correlations between CVP with CI and SVI were poor.
  
  
  CONCLUSIONS
  TPTD can accurately and precisely measure CO in different blood volume conditions. ITBVI measured by TPTD has better validity for the assessment of circulatory volume status than CVP.
authors.affiliation: Department of Pediatric Cardiology,Beijing Anzhen Hospital,Capital Medical University,Beijing 100029,China.
authors.forename: Chen
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Department of Cardiology,Children's Hospital of Fudan University,Shanghai 200032,China.
authors.forename: Xue-cun
authors.initials: XC
authors.lastname: Liang
authors.affiliation: Department of Cardiology,Children's Hospital of Fudan University,Shanghai 200032,China.
authors.forename: Guo-ying
authors.initials: GY
authors.lastname: Huang
authors.affiliation: Department of Cardiology,Children's Hospital of Fudan University,Shanghai 200032,China.
authors.forename: Feng
authors.initials: F
authors.lastname: Sheng
authors.affiliation: Department of Cardiology,Children's Hospital of Fudan University,Shanghai 200032,China.
authors.forename: Yu-yang
authors.initials: YY
authors.lastname: Liu
mesh_terms: D000818:Animals; D001810:Blood Volume; D002302:Cardiac Output; D013552:Swine; D013815:Thermodilution