title: Change in Diaphragmatic Thickness During the Respiratory Cycle Predicts Extubation Success at Various Levels of Pressure Support Ventilation.
abstract: Ultrasonographic assessment of diaphragm function with patients on low levels of pressure support (PS) predicts extubation outcomes, but similar information regarding extubation success under other conditions is lacking. The purpose of this study was to determine whether ultrasound (US) measurements of the diaphragm made on various levels of PS can predict time until successful extubation.
  
  
  
  Fifty-six intubated patients underwent ultrasound of the right hemidiaphragm during a PS wean at varying levels of pressure support (PS 5/5 cm of H2O, 10/5 cm of H2O, and 15/5 cm of H2O). The diaphragm was visualized using a 7.5-10 mHz transducer in the zone of apposition of the diaphragm to the lower rib cage. The percent change in diaphragm thickness between end-expiration and end-inspiration (∆tdi%) was calculated at each level of PS.
  
  
  
  ∆tdi% >20 is a robust predictor of extubation success within 48 h of US at PS 5/5 cm of H2O and 10/5 cm of H2O (sensitivity 84.6 and 88.9 % and specificity 79.0 and 75.0 %, respectively). At PS greater than 10/5 cm of H2O, its predictive power was greatly diminished. Of nine patients who were extubated with ∆tdi% below the cutoff, 66.6 % required emergent reintubation in the next two days.
  
  
  
  Diaphragm US is a valid predictor of extubation success at some but not all PS settings. Using a ∆tdi% of 20 % on PS levels up to 10/5 cm of H2O may reduce both unnecessarily prolonged intubations and prevent emergent reintubations.
authors.affiliation: Department of Internal Medicine, Einstein Medical Center, Philadelphia, PA, USA.
authors.forename: Scott
authors.identifier: 0000-0002-8673-3621
authors.initials: S
authors.lastname: Blumhof
authors.affiliation: Department of Internal Medicine, Einstein Medical Center, Philadelphia, PA, USA.
authors.forename: David
authors.initials: D
authors.lastname: Wheeler
authors.affiliation: Department of Pulmonary and Critical Care Medicine, Einstein Medical Center, 5501 Old York Rd., Philadelphia, PA, 19141, USA.
authors.forename: Kendol
authors.initials: K
authors.lastname: Thomas
authors.affiliation: Department of Pulmonary, Critical Care, and Sleep Medicine, Memorial Hospital of Rhode Island and Brown University, Pawtucket, RI, USA.
authors.forename: F Dennis
authors.initials: FD
authors.lastname: McCool
authors.affiliation: Department of Pulmonary and Critical Care Medicine, Einstein Medical Center, 5501 Old York Rd., Philadelphia, PA, 19141, USA. morajor@einstein.edu.
authors.forename: Jorge
authors.initials: J
authors.lastname: Mora
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D060666:Airway Extubation; D019540:Area Under Curve; D003964:Diaphragm / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D011237:Predictive Value of Tests; D012372:ROC Curve; D012119:Respiration; D013997:Time Factors; D014463:Ultrasonography; D015300:Ventilator Weaning
keywords: Diaphragm; Extubation; Mechanical ventilation; Ultrasound; Weaning