title: Comparison of transpulmonary thermodilution and ultrasound dilution technique: novel insights into volumetric parameters from an animal model.
abstract: Especially in critically ill children with cardiac diseases, fluid management and monitoring of cardiovascular function are essential. Ultrasound dilution technique (UDT) was recently introduced to measure cardiac output (CO) and volumetric parameters, such as intrathoracic and end-diastolic blood volume. We compared UDT with the well-established transpulmonary thermodilution (TPTD) method (PiCCO) for determining CO measurements and derived volumes in a juvenile animal model. Experiments were performed in 18 ventilated, anesthetized piglets during normovolemia and after isovolemic hemodilution. At baseline and 20 min after each step of isovolemic hemodilution, 3 independent measurements of CO and volumetric parameters were conducted with TPTD and UDT, consecutively, under hemodynamically stable conditions. We observed comparable results for CO measurements with both methods (mean 1.98 l/min; range 1.12-2.87) with a percentage error of 17.3% (r = 0.92, mean bias = 0.28 l/min). Global end-diastolic volume (GEDV) and intrathoracic blood volume (ITBV) by TPTD were almost two times greater than analogous volumes [central blood volume (CBV); total end-diastolic volume (TEDV)] quantified by UDT (CBV = 0.58 × ITBV + 27.1 ml; TEDV = 0.48 × GEDV + 23.1 ml). CO measurements by UDT were found to be equivalent and hence interchangeable with TPTD. Discrepancies in volumetric parameters could either be due to the underlying algorithm or different types of indicators (diffusible vs. nondiffusible). Compared with the anatomically defined heart volume, TPTD seems to overestimate end-diastolic volumes. Future studies will be necessary to assign these results to critically ill children and to validate volumetric parameters with reference techniques.
authors.affiliation: Department of Pediatric Cardiology and Intensive Care Medicine, Hannover Medical School, Hannover, Germany. boehne.martin@mh-hannover.de
authors.forename: Martin
authors.initials: M
authors.lastname: Boehne
authors.forename: Florian
authors.initials: F
authors.lastname: Schmidt
authors.forename: Lars
authors.initials: L
authors.lastname: Witt
authors.forename: Harald
authors.initials: H
authors.lastname: Köditz
authors.forename: Michael
authors.initials: M
authors.lastname: Sasse
authors.forename: Robert
authors.initials: R
authors.lastname: Sümpelmann
authors.forename: Harald
authors.initials: H
authors.lastname: Bertram
authors.forename: Armin
authors.initials: A
authors.lastname: Wessel
authors.forename: Wilhelm Alexander
authors.initials: WA
authors.lastname: Osthaus
mesh_terms: D000818:Animals; D001810:Blood Volume / Q000502:physiology*; D002302:Cardiac Output; D002306:Cardiac Volume / Q000502:physiology*; D002318:Cardiovascular Diseases / Q000175:diagnosis* / Q000503:physiopathology; D016638:Critical Illness; D003971:Diastole; D004195:Disease Models, Animal; D005260:Female; D008991:Monitoring, Physiologic / Q000379:methods*; D009200:Myocardial Contraction / Q000502:physiology*; D015203:Reproducibility of Results; D013552:Swine; D013815:Thermodilution / Q000379:methods*