title: Occlusion pressure and its ratio to maximum inspiratory pressure are useful predictors for successful extubation following T-piece weaning trial.
abstract: OBJECTIVE
  In most weaning studies, failure group patients are reventilated prior to extubation, thus compromising the evaluation of the applied weaning indices' predictive values. This study determines the usefulness of both standard and recent indices in predicting successful extubation following prolonged mechanical ventilation.
  
  
  METHODS
  Following a successful 20-min T-piece trial, ten traditional weaning criteria, as well as airway occlusion pressure (PO.1), maximal inspiratory pressure (MIP), PO.1/MIP ratio, and shallow breathing (F/VT) were determined in unselected patients undergoing prolonged mechanical ventilation. Having satisfied 8 of 10 classic weaning criteria, 67 patients were extubated after an additional 40 min of successful spontaneous T-piece breathing, and included in the study. After extubation, the tracheal tube resistive pressure (RP) values were measured.
  
  
  RESULTS
  Twelve (18%) patients failed extubation. The failure group's average age was significantly greater (69.43 vs 48.43 years). The PO.1, PO.1/MIP, and F/VT values of the success (3.62 +/- 1.35 cm H2O, 0.05 +/- 0.04, and 50 +/- 23 b.min-1.L-1) and failure (7.38 +/- 2.67 cm H2O, 0.14 +/- 0.04, and 69 +/- 25 b.min-1.L-1) groups were significantly different (p < 0.005). The diagnostic accuracies of these indices were, respectively, 88%, 98%, and 73%. The spirometric, gas exchange, and tracheal tube RP values of the two groups showed no significant differences.
  
  
  CONCLUSIONS
  PO.1 and PO.1/MIP ratio provide the best means of predicting extubation success, and they are not influenced by tracheal tube resistance.
authors.affiliation: Département d'Anesthésie Réanimation A, Hôpital Lapeyronie, Montpellier, France.
authors.forename: X J
authors.initials: XJ
authors.lastname: Capdevila
authors.forename: P F
authors.initials: PF
authors.lastname: Perrigault
authors.forename: P J
authors.initials: PJ
authors.lastname: Perey
authors.forename: J P
authors.initials: JP
authors.lastname: Roustan
authors.forename: F
authors.initials: F
authors.lastname: d'Athis
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012372:ROC Curve; D012121:Respiration, Artificial; D012131:Respiratory Insufficiency / Q000503:physiopathology / Q000628:therapy; D015656:Respiratory Mechanics / Q000502:physiology*; D012680:Sensitivity and Specificity; D013147:Spirometry / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D018709:Statistics, Nonparametric; D013997:Time Factors; D017211:Treatment Failure; D015300:Ventilator Weaning / Q000379:methods* / Q000706:statistics & numerical data