title: Patient-ventilator interaction and sleep in mechanically ventilated patients: pressure support versus proportional assist ventilation.
abstract: OBJECTIVE
  To understand the role of patient-ventilator asynchrony in the etiology of sleep disruption and determine whether optimizing patient-ventilator interactions by using proportional assist ventilation improves sleep.
  
  
  METHODS
  Randomized crossover clinical trial.
  
  
  METHODS
  A tertiary university medical-surgical intensive care unit.
  
  
  METHODS
  Thirteen patients during weaning from mechanical ventilation.
  
  
  METHODS
  Patients were randomized to receive pressure support ventilation or proportional assist ventilation on the first night and then crossed over to the alternative mode for the second night. Polysomnography and measurement of light, noise, esophageal pressure, airway pressure, and flow were performed from 10 pm to 8 am. Ventilator settings (pressure level during pressure support ventilation and resistive and elastic proportionality factors during proportional assist ventilation) were set to obtain a 50% reduction of the inspiratory work (pressure time product per minute) performed during a spontaneous breathing trial.
  
  
  RESULTS
  Arousals per hour of sleep time during pressure support ventilation were 16 (range 2-74) and 9 (range 1-41) during proportional assist ventilation (p = .02). Overall sleep quality was significantly improved on proportional assist ventilation (p < .05) due to the combined effect of fewer arousals per hour, fewer awakenings per hour (3.5 [0-24] vs. 5.5 [1-24]), and greater rapid eye movement (9% [0-31] vs. 4% [0-23]), and slow wave (3% [0-16] vs. 1% [0-10]) sleep. Tidal volume and minute ventilation were lower on proportional assist ventilation, allowing for a greater increase in Paco2 during the night. Patient-ventilator asynchronies per hour were lower with proportional assist ventilation than with pressure support ventilation (24 +/- 15 vs. 53 +/- 59; p = .02) and correlated with the number of arousals per hour (R = .65, p = .0001).
  
  
  CONCLUSIONS
  Patient ventilator discordance causes sleep disruption. Proportional assist ventilation seems more efficacious than pressure support ventilation in matching ventilatory requirements with ventilator assistance, therefore resulting in fewer patient-ventilator asynchronies and better quality of sleep.
authors.affiliation: Dipartimento di Anestesiologia e Rianimazione, Università di Torino, Ospedale S. Giovanni Battista-Molinette, Torino, Italy.
authors.forename: Karen
authors.initials: K
authors.lastname: Bosma
authors.forename: Gabriela
authors.initials: G
authors.lastname: Ferreyra
authors.forename: Cristina
authors.initials: C
authors.lastname: Ambrogio
authors.forename: Daniela
authors.initials: D
authors.lastname: Pasero
authors.forename: Lucia
authors.initials: L
authors.lastname: Mirabella
authors.forename: Alberto
authors.initials: A
authors.lastname: Braghiroli
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Appendini
authors.forename: Luciana
authors.initials: L
authors.lastname: Mascia
authors.forename: V Marco
authors.initials: VM
authors.lastname: Ranieri
mesh_terms: D000328:Adult; D000368:Aged; D001143:Arousal; D018592:Cross-Over Studies; D005260:Female; D006785:Hospitals, University; D006801:Humans; D007362:Intensive Care Units; D008027:Light; D008297:Male; D008875:Middle Aged; D009622:Noise; D017286:Polysomnography; D012121:Respiration, Artificial / Q000009:adverse effects* / Q000379:methods*; D012890:Sleep