title: Effects of different continuous positive airway pressure devices and periodic hyperinflations on respiratory function.
abstract: OBJECTIVE
  To compare the effect on respiratory function of different continuous positive airway pressure systems and periodic hyperinflations in patients with respiratory failure.
  
  
  METHODS
  Prospective
  
  
  METHODS
  Hospital intensive care unit.
  
  
  METHODS
  Sixteen intubated patients (eight men and eight women, age 54 +/- 18 yrs, PaO2/FiO2 277 +/- 58 torr, positive end-expiratory pressure 6.2 +/- 2.0 cm H2O).
  
  
  METHODS
  We evaluated continuous flow positive airway pressure systems with high or low flow plus a reservoir bag equipped with spring-loaded mechanical or underwater seal positive end-expiratory pressure valve and a continuous positive airway pressure by a Servo 300 C ventilator with or without periodic hyperinflations (three assisted breaths per minute with constant inspiratory pressure of 30 cm H2O over positive end-expiratory pressure).
  
  
  RESULTS
  We measured the respiratory pattern, work of breathing, dyspnea sensation, end-expiratory lung volume, and gas exchange. We found the following: a) Work of breathing and gas exchange were comparable between continuous flow systems; b) the ventilator continuous positive airway pressure was not different compared with continuous flow systems; and c) continuous positive airway pressure with periodic hyperinflations reduced work of breathing (10.7 +/- 9.5 vs. 6.3 +/- 5.7 J/min, p <.05) and dyspnea sensation (1.6 +/- 1.2 vs. 1.1 +/- 0.8 cm, p <.05) increased end-expiratory lung volume (1.6 +/- 0.8 vs. 2.0 +/- 0.9 L, p <.05) and PaO2 (100 +/- 21 vs. 120 +/- 25 torr, p <.05) compared with ventilator continuous positive airway pressure.
  
  
  CONCLUSIONS
  The continuous flow positive airway pressure systems tested are equally efficient; a ventilator can provide satisfactory continuous positive airway pressure; and the use of periodic hyperinflations during continuous positive airway pressure can improve respiratory function and reduce the work of breathing.
authors.affiliation: Dipartimento di Scienze Cliniche e Biologiche, Università degli Studi dell'Insubria, Varese, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Pelosi
authors.forename: D
authors.initials: D
authors.lastname: Chiumello
authors.forename: E
authors.initials: E
authors.lastname: Calvi
authors.forename: P
authors.initials: P
authors.lastname: Taccone
authors.forename: N
authors.initials: N
authors.lastname: Bottino
authors.forename: M
authors.initials: M
authors.lastname: Panigada
authors.forename: P
authors.initials: P
authors.lastname: Cadringher
authors.forename: L
authors.initials: L
authors.lastname: Gattinoni
mesh_terms: D000328:Adult; D000368:Aged; D003422:Critical Care; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D011175:Positive-Pressure Respiration / Q000379:methods*; D011659:Pulmonary Gas Exchange; D012131:Respiratory Insufficiency / Q000628:therapy*; D014939:Work of Breathing