title: Comparison of oxygen cost of breathing with pressure-support ventilation and biphasic intermittent positive airway pressure ventilation.
abstract: OBJECTIVE
  To assess the oxygen cost of breathing with either pressure-support ventilation (PSV) or biphasic intermittent positive airway pressure ventilation (BIPAP).
  
  
  METHODS
  Prospective, randomized, crossover study.
  
  
  METHODS
  Medical intensive care unit of a university hospital.
  
  
  METHODS
  Twenty clinically stable and spontaneously breathing patients after long-term mechanical ventilation.
  
  
  METHODS
  Patients were randomized to start on either PSV or BIPAP, and measurements were performed after an adaptation period of 30 mins. Immediately after, the ventilatory mode was changed and after another 30-min adaptation period, the same measurements were performed.
  
  
  RESULTS
  Indirect calorimetry was performed during each ventilatory mode for a period of 30 mins. Oxygen consumption, energy expenditure, CO2 production, and respiratory quotient did not differ significantly between the two ventilatory modes, regardless of the patients' randomization. There were no statistically significant differences with regard to respiratory rate, minute volume, and blood gas analysis. All patients tolerated both ventilatory modes without any signs of discomfort.
  
  
  CONCLUSIONS
  Pressure support ventilation and BIPAP are both used for weaning patients gradually from the ventilator. BIPAP may be advantageous in patients not breathing sufficiently with PSV, since no patient effort is necessary with use of this ventilatory mode.
authors.affiliation: Department of Internal Medicine, University of Vienna, Austria.
authors.forename: T
authors.initials: T
authors.lastname: Staudinger
authors.forename: H
authors.initials: H
authors.lastname: Kordova
authors.forename: M
authors.initials: M
authors.lastname: Röggla
authors.forename: P
authors.initials: P
authors.lastname: Tesinsky
authors.forename: G J
authors.initials: GJ
authors.lastname: Locker
authors.forename: K
authors.initials: K
authors.lastname: Laczika
authors.forename: S
authors.initials: S
authors.lastname: Knapp
authors.forename: M
authors.initials: M
authors.lastname: Frass
mesh_terms: D000328:Adult; D000368:Aged; D002153:Calorimetry, Indirect; D018592:Cross-Over Studies; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D007385:Intermittent Positive-Pressure Ventilation / Q000379:methods; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D011446:Prospective Studies; D014939:Work of Breathing