title: Ultrasonographic diaphragmatic excursion is inaccurate and not better than the MRC score for predicting weaning-failure in mechanically ventilated patients.
abstract: OBJECTIVE
  To assess the ability of diaphragmatic ultrasound (US) to predict weaning failure in mechanically ventilated patients undergoing a first spontaneous breathing trial (SBT).
  
  
  METHODS
  During a 4-month period, 67 consecutive patients eligible for a first SBT underwent US measurements of maximal diaphragmatic excursion (MDE) by a right anterior subcostal approach. Weaning failure was defined as either the failure of SBT or the need for resumption of ventilatory support for acute respiratory failure or death within 48h following successful extubation. The accuracy of diaphragmatic ultrasound and the Medical Research Council (MRC) score when predicting weaning failure was assessed via a receiver operating curve analysis.
  
  
  RESULTS
  The feasibility rate for the ultrasound measurements was 63%. Mean values of MDE were significantly higher in patients who succeeded at their first weaning attempt (4.1±2.1 versus 3±1.8cm, P=0.04). Using a threshold of MDE≤2.7cm, the sensitivity and specificity of diaphragmatic ultrasound in predicting weaning failure were 59% [39-77%] and 71% [57-82%] with an AUC at 0.65 [0.51-0.78]. There was no significant difference between MDE values and MRC scores for predicting weaning failure (P=0.73).
  
  
  CONCLUSIONS
  A decrease in MDE values may be associated with an unfavourable weaning outcome. Diaphragmatic excursion measured by ultrasound is however unable by itself to predict weaning failure at the bedside of patients undergoing a first spontaneous breathing trial and does not provide any additional value compared to the MRC score.
authors.affiliation: Critical Care Department, Centre Hospitalier Robert Boulin, 33500 Libourne, France. Electronic address: cedric.carrie@ch-libourne.fr.
authors.forename: Cédric
authors.initials: C
authors.lastname: Carrie
authors.affiliation: Medical Critical Care Department, CHU Bordeaux, 33000 Bordeaux, France.
authors.forename: Chloé
authors.initials: C
authors.lastname: Gisbert-Mora
authors.affiliation: Critical Care Department, Centre Hospitalier Robert Boulin, 33500 Libourne, France.
authors.forename: Eline
authors.initials: E
authors.lastname: Bonnardel
authors.affiliation: Medical Critical Care Department, CHU Bordeaux, 33000 Bordeaux, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Gauche
authors.affiliation: Anaesthesiology and Critical Care Department III, CHU Bordeaux, 33000 Bordeaux, France; Univ. Bordeaux Segalen, 33000 Bordeaux, France.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Biais
authors.affiliation: Medical Critical Care Department, CHU Bordeaux, 33000 Bordeaux, France; Univ. Bordeaux Segalen, 33000 Bordeaux, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Vargas
authors.affiliation: Medical Critical Care Department, CHU Bordeaux, 33000 Bordeaux, France; Univ. Bordeaux Segalen, 33000 Bordeaux, France.
authors.forename: Gilles
authors.initials: G
authors.lastname: Hilbert
mesh_terms: D000368:Aged; D060666:Airway Extubation; D003964:Diaphragm / Q000000981:diagnostic imaging*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D015203:Reproducibility of Results; D012119:Respiration; D012121:Respiration, Artificial / Q000379:methods; D017211:Treatment Failure; D014463:Ultrasonography; D015300:Ventilator Weaning / Q000379:methods*
keywords: Diaphragmatic dysfunction; Diaphragmatic ultrasound; Intensive Care Medicine; Mechanical ventilation; Weaning failure