title: Impact of ventilation parameters and duration of ventilator use on non-invasive home ventilation in restrictive thoracic disorders.
abstract: BACKGROUND
  Non-invasive positive pressure ventilation (NPPV) is an accepted treatment option for chronic ventilatory failure due to restrictive thoracic disorders.
  
  
  OBJECTIVE
  The impact of ventilation setting and the duration of ventilator use on changes in physiological and functional parameters has not yet been evaluated.
  
  
  METHODS
  Effects of NPPV on body plethysmographic parameters, blood gas tension and inspiratory muscle function up to 12 months were analyzed in 44 patients with thoracic cage abnormalities in a clinical stable condition. Furthermore, the influence of ventilator parameters and the duration of ventilator use on these changes was determined.
  
  
  RESULTS
  A significant improvement in blood gas parameters (PaCO(2), PaO(2) and base excess; p < 0.001), lung volumes (VC, TLC and FEV(1); p < 0.001) and inspiratory muscle function (PI(max), P(0.1); p < 0.01 and p < 0.05) was found after 3.8 +/- 0.8 months of treatment. As shown by a subgroup analysis, changes were already achieved within the first 3 months of NPPV and then remained stable over time. Improvements in VC were positively correlated with IPAP (r = 0.55; p < 0.001). Reduction in PaCO(2) was positively correlated with the quotient (IPAP - EPAP)/weight (r = 0.55; p < 0.001). No correlation could be detected between changes in functional parameters and the duration of ventilator use.
  
  
  CONCLUSIONS
  NPPV can improve blood gas parameters, lung volume and inspiratory muscle function in thoracic restrictive disorders. To best utilize the potential of NPPV treatment, it seems to be more effective to optimize pressure levels than to extend the duration of ventilation.
authors.affiliation: Centre of Pneumology, Hospital Donaustauf, Donaustauf, Germany. stephan.budweiser@klinik.uni-regensburg.de
authors.forename: Stephan
authors.initials: S
authors.lastname: Budweiser
authors.forename: Frank
authors.initials: F
authors.lastname: Heinemann
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Fischer
authors.forename: Jakob
authors.initials: J
authors.lastname: Dobroschke
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Wild
authors.forename: Michael
authors.initials: M
authors.lastname: Pfeifer
mesh_terms: D001784:Blood Gas Analysis; D004417:Dyspnea / Q000097:blood / Q000209:etiology / Q000628:therapy; D005500:Follow-Up Studies; D005541:Forced Expiratory Volume; D006699:Home Care Services; D006801:Humans; D006935:Hypercapnia / Q000097:blood / Q000209:etiology / Q000628:therapy; D010045:Outpatients; D010991:Plethysmography; D011175:Positive-Pressure Respiration / Q000379:methods*; D015656:Respiratory Mechanics / Q000502:physiology*; D012189:Retrospective Studies; D013896:Thoracic Diseases / Q000097:blood / Q000150:complications / Q000503:physiopathology*; D013997:Time Factors