title: Mechanical Ventilation and Diaphragmatic Atrophy in Critically Ill Patients: An Ultrasound Study.
abstract: OBJECTIVE
  Mechanical ventilation contributes to diaphragmatic atrophy and dysfunction, and few techniques exist to assess diaphragmatic function: the purpose of this study was to quantify diaphragm atrophy in a population of critically ill mechanically ventilated patients with ultrasound and to identify risk factors that can worsen diaphragmatic activity.
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  ICU of a 1,200-bed university hospital.
  
  
  METHODS
  Newly intubated adult critically ill patients.
  
  
  METHODS
  Diaphragm thickness in the zone of apposition was measured daily with ultrasound, from the first day of mechanical ventilation till discharge to the main ward.
  
  
  RESULTS
  Daily atrophy rate (ΔTdi/d) was calculated as the reduction in percentage from the previous measurement. To analyze the difference in atrophy rate (ΔTdi/d), ventilation was categorized into four classes: spontaneous breathing or continuous positive airway pressure; pressure support ventilation 5-12 cm H2O (low pressure support ventilation); pressure support ventilation greater than 12 cm H2O (high pressure support ventilation); and controlled mechanical ventilation. Multivariate analysis with ventilation support and other clinical variables was performed to identify risk factors for atrophy. Forty patients underwent a total of 153 ultrasonographic evaluations. Mean (SD) ΔTdi/d was -7.5% (12.3) during controlled mechanical ventilation, -5.3% (12.9) at high pressure support ventilation, -1.5% (10.9) at low pressure support ventilation, +2.3% (9.5) during spontaneous breathing or continuous positive airway pressure. At multivariate analysis, only the ventilation support was predictive of diaphragm atrophy rate. Pressure support predicted diaphragm thickness with coefficient -0.006 (95% CI, -0.010 to -0.002; p = 0.006).
  
  
  CONCLUSIONS
  In critically ill mechanically ventilated patients, there is a linear relationship between ventilator support and diaphragmatic atrophy rate.
authors.affiliation: 1Department of Anesthesia and Intensive Care, IRCCS San Raffaele Scientific Institute, Milan, Italy. 2Vita-Salute San Raffaele University, Milan, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Zambon
authors.forename: Paolo
authors.initials: P
authors.lastname: Beccaria
authors.forename: Jun
authors.initials: J
authors.lastname: Matsuno
authors.forename: Marco
authors.initials: M
authors.lastname: Gemma
authors.forename: Elena
authors.initials: E
authors.lastname: Frati
authors.forename: Sergio
authors.initials: S
authors.lastname: Colombo
authors.forename: Luca
authors.initials: L
authors.lastname: Cabrini
authors.forename: Giovanni
authors.initials: G
authors.lastname: Landoni
authors.forename: Alberto
authors.initials: A
authors.lastname: Zangrillo
mesh_terms: D000328:Adult; D000368:Aged; D001284:Atrophy; D016638:Critical Illness; D003964:Diaphragm / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D006785:Hospitals, University; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012121:Respiration, Artificial / Q000009:adverse effects*; D014463:Ultrasonography; D012122:Ventilators, Mechanical