title: A computer-based matrix for rapid calculation of pulmonary hemodynamic parameters in congenital heart disease.
abstract: BACKGROUND
  In patients with congenital heart disease undergoing cardiac catheterization for hemodynamic purposes, parameter estimation by the indirect Fick method using a single predicted value of oxygen consumption has been a matter of criticism.
  
  
  OBJECTIVE
  We developed a computer-based routine for rapid estimation of replicate hemodynamic parameters using multiple predicted values of oxygen consumption.
  
  
  METHODS
  Using Microsoft® Excel facilities, we constructed a matrix containing 5 models (equations) for prediction of oxygen consumption, and all additional formulas needed to obtain replicate estimates of hemodynamic parameters.
  
  
  RESULTS
  By entering data from 65 patients with ventricular septal defects, aged 1 month to 8 years, it was possible to obtain multiple predictions for oxygen consumption, with clear between-age groups (P <.001) and between-methods (P <.001) differences. Using these predictions in the individual patient, it was possible to obtain the upper and lower limits of a likely range for any given parameter, which made estimation more realistic.
  
  
  CONCLUSIONS
  The organized matrix allows for rapid obtainment of replicate parameter estimates, without error due to exhaustive calculations.
authors.affiliation: Department of Pediatric Cardiology and Adult Congenital Heart Disease, Heart Institute (InCor), School of Medicine, University of São Paulo, São Paulo, Brazil. aablopes@usp.br
authors.forename: Antonio Augusto
authors.initials: AA
authors.lastname: Lopes
authors.forename: Rogério
authors.initials: R
authors.lastname: Dos Anjos Miranda
authors.forename: Rilvani Cavalcante
authors.initials: RC
authors.lastname: Gonçalves
authors.forename: Ana Maria
authors.initials: AM
authors.lastname: Thomaz