title: An open-source software for automatic calculation of respiratory parameters based on esophageal pressure.
abstract: OBJECTIVE
  We have developed a software that automatically calculates respiratory effort indices, including intrinsic end expiratory pressure (PEEPi) and esophageal pressure-time product (PTPeso).
  
  
  METHODS
  The software first identifies respiratory periods. Clean signals are averaged to provide a reference mean cycle from which respiratory parameters are extracted. The onset of the inspiratory effort is detected automatically by looking backward from the onset of inspiratory flow to the first point where the esophageal pressure derivative is equal to zero (inflection point). PEEPi is derived from this point. Twenty-three recordings from 16 patients were analyzed with the algorithm and compared with experts' manual analysis of signals: 15 recordings were performed during spontaneous breathing, 1 during non-invasive mechanical ventilation, and 7 under both conditions.
  
  
  RESULTS
  For all values, the coefficients of determinations (r(2)) exceeded 0.94 (p<0.001). The bias (mean difference) between PEEPi calculated by hand and automatically was -0.26±0.52cmH2O during spontaneous breathing and the precisions (standard deviations of the differences) was 0.52cmH2O with limits of agreement of 0.78 and -1.30cmH2O. The mean difference between PTPeso calculated by hand and automatically was -0.38±1.42cmH2Os/cycle with limits of agreement of 2.46 and -3.22cmH2Os/cycle.
  
  
  CONCLUSIONS
  Our program provides a reliable method for the automatic calculation of PEEPi and respiratory effort indices, which may facilitate the use of these variables in clinical practice. The software is open source and can be improved with the development and validation of new respiratory parameters.
authors: INSERM, Centre d'Investigation Clinique et d'Innovation technologique (CICIT), UMR805, Garches, France; EA4497, Université Versailles Saint-Quentin (UVSQ), Versailles, France; Hôpital Raymond Poincaré, APHP, Garches, France; Institute of Biomedical Engineering (IBME), University of Oxford, Oxford, UK. Electronic address: louis.mayaud@gmail.com.
authors: Louis
authors: L
authors: Mayaud
authors: INSERM, Centre d'Investigation Clinique et d'Innovation technologique (CICIT), UMR805, Garches, France; EA4497, Université Versailles Saint-Quentin (UVSQ), Versailles, France; Hôpital Raymond Poincaré, APHP, Garches, France.
authors: Michèle
authors: M
authors: Lejaille
authors: INSERM, Centre d'Investigation Clinique et d'Innovation technologique (CICIT), UMR805, Garches, France; EA4497, Université Versailles Saint-Quentin (UVSQ), Versailles, France; Hôpital Raymond Poincaré, APHP, Garches, France.
authors: Hélène
authors: H
authors: Prigent
authors: INSERM U955, 94000 Créteil, France.
authors: Bruno
authors: B
authors: Louis
authors: Pediatric Pulmonology, Hopital Armand Trousseau, AP-HP, and Pierre et Marie Curie University, Paris, France.
authors: Brigitte
authors: B
authors: Fauroux
authors: INSERM, Centre d'Investigation Clinique et d'Innovation technologique (CICIT), UMR805, Garches, France; EA4497, Université Versailles Saint-Quentin (UVSQ), Versailles, France; Hôpital Raymond Poincaré, APHP, Garches, France.
authors: Frédéric
authors: F
authors: Lofaso
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D002648:Child; D001330:Electronic Data Processing / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011175:Positive-Pressure Respiration; D018467:Positive-Pressure Respiration, Intrinsic / Q000175:diagnosis*; D015203:Reproducibility of Results; D012119:Respiration; D012132:Respiratory Muscles / Q000502:physiology*; D012984:Software; D055815:Young Adult
keywords: Acute respiratory failure; CLdyn; Ccw; EEV; Esophageal pressure; F; FRC; ID; IVC; M; MV; NIVM; PEEPi; PTPdi; PV; Pdi; Peso; Pga; Pmask; Pressure time product; Ptp; RSR; RV; Respiratory function; SB; TLC; Ti; VT; WOB; chest wall compliance; dynamic lung compliance; end-expiratory volume; female; functional residual capacity; gastric pressure; identification; inspiratory time; inspiratory vital capacity; intrinsic positive end expiratory pressure; male; mask pressure; mechanical ventilation; non-invasive mechanical ventilation; oesophageal pressure; pressure–volume; residual volume; respiratory system resistance; spontaneous breathing; tidal volume; total lung capacity; transdiaphragmatic pressure; transdiaphragmatic product time product; transpulmonary pressure; work of breathing