title: Noninvasive work of breathing improves prediction of post-extubation outcome.
abstract: OBJECTIVE
  We hypothesized that non-invasively determined work of breathing per minute (WOB(N)/min) (esophageal balloon not required) may be useful for predicting extubation outcome, i.e., appropriate work of breathing values may be associated with extubation success, while inappropriately increased values may be associated with failure.
  
  
  METHODS
  Adult candidates for extubation were divided into a training set (n = 38) to determine threshold values of indices for assessing extubation and a prospective validation set (n = 59) to determine the predictive power of the threshold values for patients successfully extubated and those who failed extubation. All were evaluated for extubation during a spontaneous breathing trial (5 cmH(2)O pressure support ventilation, 5 cmH(2)O positive end expiratory pressure) using routine clinical practice standards. WOB(N)/min data were blinded to attending physicians. Area under the receiver operating characteristic curves (AUC), sensitivity, specificity, and positive and negative predictive values of all extubation indices were determined.
  
  
  RESULTS
  AUC for WOB(N)/min was 0.96 and significantly greater (p < 0.05) than AUC for breathing frequency at 0.81, tidal volume at 0.61, breathing frequency-to-tidal volume ratio at 0.73, and other traditionally used indices. WOB(N)/min had a specificity of 0.83, the highest sensitivity at 0.96, positive predictive value at 0.84, and negative predictive value at 0.96 compared to all indices. For 95% of those successfully extubated, WOB(N)/min was ≤10 J/min.
  
  
  CONCLUSIONS
  WOB(N)/min had the greatest overall predictive accuracy for extubation compared to traditional indices. WOB(N)/min warrants consideration for use in a complementary manner with spontaneous breathing pattern data for predicting extubation outcome.
authors: Department of Anesthesiology, College of Medicine, University of Florida, P.O. Box 100254, Gainesville, FL 32608, USA. mbanner@anest.ufl.edu
authors: Michael J
authors: MJ
authors: Banner
authors: Neil R
authors: NR
authors: Euliano
authors: A Daniel
authors: AD
authors: Martin
authors: Nawar
authors: N
authors: Al-Rawas
authors: A Joseph
authors: AJ
authors: Layon
authors: Andrea
authors: A
authors: Gabrielli
mesh_terms: D060666:Airway Extubation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D017211:Treatment Failure; D015300:Ventilator Weaning; D014939:Work of Breathing