title: Beat-to-beat estimation of the continuous left and right cardiac elastance from metrics commonly available in clinical settings.
abstract: BACKGROUND
  Functional time-varying cardiac elastances (FTVE) contain a rich amount of information about the specific cardiac state of a patient. However, a FTVE waveform is very invasive to directly measure, and is thus currently not used in clinical practice. This paper presents a method for the estimation of a patient specific FTVE, using only metrics that are currently available in a clinical setting.
  
  
  METHODS
  Correlations are defined between invasively measured FTVE waveforms and the aortic and pulmonary artery pressures from 2 cohorts of porcine subjects, 1 induced with pulmonary embolism, the other with septic shock. These correlations are then used to estimate the FTVE waveform based on the individual aortic and pulmonary artery pressure waveforms, using the "other" dysfunction's correlations as a cross validation.
  
  
  RESULTS
  The cross validation resulted in 1.26% and 2.51% median errors for the left and right FTVE respectively on pulmonary embolism, while the septic shock cohort had 2.54% and 2.90% median errors.
  
  
  CONCLUSIONS
  The presented method accurately and reliably estimated a patient specific FTVE, with no added risk to the patient. The cross validation shows that the method is not dependent on dysfunction and thus has the potential for generalisation beyond pulmonary embolism and septic shock.
authors.affiliation: Department of Mechanical Engineering, Centre for Bio Engineering at the University of Canterbury, Christchurch, New Zealand.
authors.forename: David
authors.initials: D
authors.lastname: Stevenson
authors.forename: James
authors.initials: J
authors.lastname: Revie
authors.forename: J Geoffrey
authors.initials: JG
authors.lastname: Chase
authors.forename: Christopher E
authors.initials: CE
authors.lastname: Hann
authors.forename: Geoffrey M
authors.initials: GM
authors.lastname: Shaw
authors.forename: Bernard
authors.initials: B
authors.lastname: Lambermont
authors.forename: Alexandre
authors.initials: A
authors.lastname: Ghuysen
authors.forename: Philippe
authors.initials: P
authors.lastname: Kolh
authors.forename: Thomas
authors.initials: T
authors.lastname: Desaive
mesh_terms: D000818:Animals; D006321:Heart / Q000502:physiology*; D006801:Humans; D007362:Intensive Care Units; D013552:Swine; D013997:Time Factors; D058067:Wavelet Analysis