title: Modelling of the nonlinear end-systolic pressure-volume relation and volume-at-zero-pressure in porcine experiments.
abstract: The End-Systolic Pressure-Volume Relation (ESPVR) is generally modelled as a linear relationship between P and V as cardiac reflexes, such as the baroreflex, are typically suppressed in experiments. However, ESPVR has been observed to behave in a curvilinear fashion when cardiac reflexes are not suppressed, suggesting the curvilinear function may be more clinically appropriate. Data was gathered from 41 vena cava occlusion manoeuvres performed experimentally at a variety of PEEPs across 6 porcine specimens, and ESPVR determined for each pig. An exponential model of ESPVR was found to provide a higher correlation coefficient than a linear model in 6 out of 7 cases, and a lower Akaike Information Criterion (AIC) value in all cases. Further, the exponential ESPVR provided positive V0 values in a physiological range in 6 out of 7 cases analysed, while the linear ESPVR produced positive V0 values in only 3 out of 7 cases, suggesting linear extrapolation of ESPVR to determine V0 may be flawed.
authors.forename: Shaun M
authors.initials: SM
authors.lastname: Davidson
authors.forename: D Oliver
authors.initials: DO
authors.lastname: Kannangara
authors.forename: Chris G
authors.initials: CG
authors.lastname: Pretty
authors.forename: Shun
authors.initials: S
authors.lastname: Kamoi
authors.forename: Antoine
authors.initials: A
authors.lastname: Pironet
authors.forename: Thomas
authors.initials: T
authors.lastname: Desaive
authors.forename: J Geoffrey
authors.initials: JG
authors.lastname: Chase
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000502:physiology*; D008955:Models, Cardiovascular; D009200:Myocardial Contraction / Q000502:physiology*; D013318:Stroke Volume / Q000502:physiology*; D013552:Swine