title: Crossover study of proportional assist versus assist control ventilation.
abstract: OBJECTIVE
  To test the hypothesis that in very prematurely born infants remaining ventilated beyond the first week, proportional assist ventilation (PAV) compared with assist control ventilation (ACV) would be associated with reduced work of breathing, increased respiratory muscle strength and less ventilator-infant asynchrony which would be associated with improved oxygenation.
  
  
  METHODS
  Randomised crossover study.
  
  
  METHODS
  Tertiary neonatal unit.
  
  
  METHODS
  12 infants with a median gestational age of 25 (range 24-26) weeks were studied at a median of 43 (range 8-86) days.
  
  
  METHODS
  Infants were studied for 1 h each on PAV and ACV in random order.
  
  
  METHODS
  At the end of each hour, the work of breathing (assessed by measuring the diaphragmatic pressure time product), thoracoabdominal asynchrony and respiratory muscle strength (maximal inspiratory pressure, maximal expiratory pressure (Pemax) and maximal transdiaphragmatic pressure (Pdimax)) were assessed. Blood gas analysis was performed and the oxygenation index (OI) calculated.
  
  
  RESULTS
  After 1 h on PAV compared with 1 h on ACV, the median OI (5.55 (range 5-11) vs 10.10 (range 7-16), p=0.002) and PTP levels were lower (217 (range 59-556) cm H2O.s/min vs 309 (range 55-544) cm H2O.s/min, p=0.005), while Pdimax (44.26 (range 21-66) cm H2O vs 37.9 (range 19-45) cm H2O, p=0.002) and Pemax (25.6 (range 6.5-42) cm H2O vs 15.9 (range 3-35) cm H2O levels p=0.010) were higher.
  
  
  CONCLUSIONS
  These results suggest that PAV compared with ACV may have physiological advantages for prematurely born infants who remain ventilated after the first week after birth.
authors.affiliation: Division of Asthma, Allergy and Lung Biology, MRC Centre for Allergic Mechanisms in Asthma, King's College London, London, UK.
authors.forename: Prashanth
authors.initials: P
authors.lastname: Bhat
authors.affiliation: Division of Asthma, Allergy and Lung Biology, MRC Centre for Allergic Mechanisms in Asthma, King's College London, London, UK.
authors.forename: Deena-Shefali
authors.initials: DS
authors.lastname: Patel
authors.affiliation: Division of Asthma, Allergy and Lung Biology, MRC Centre for Allergic Mechanisms in Asthma, King's College London, London, UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Hannam
authors.affiliation: Division of Asthma, Allergy and Lung Biology, MRC Centre for Allergic Mechanisms in Asthma, King's College London, London, UK.
authors.forename: Gerrard F
authors.initials: GF
authors.lastname: Rafferty
authors.affiliation: Division of Health and Social Care Research, King's College London, London, UK NIHR Biomedical Research Centre at Guy's and St Thomas' NHS Foundation Trust and King's College London, London, UK.
authors.forename: Janet L
authors.initials: JL
authors.lastname: Peacock
authors.affiliation: Division of Asthma, Allergy and Lung Biology, MRC Centre for Allergic Mechanisms in Asthma, King's College London, London, UK.
authors.forename: Anthony D
authors.initials: AD
authors.lastname: Milner
authors.affiliation: Division of Asthma, Allergy and Lung Biology, MRC Centre for Allergic Mechanisms in Asthma, King's College London, London, UK NIHR Biomedical Research Centre at Guy's and St Thomas' NHS Foundation Trust and King's College London, London, UK.
authors.forename: Anne
authors.initials: A
authors.lastname: Greenough
mesh_terms: D001784:Blood Gas Analysis; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000628:therapy*; D059725:Interactive Ventilatory Support; D008168:Lung / Q000503:physiopathology; D008297:Male; D053580:Muscle Strength; D012121:Respiration, Artificial / Q000379:methods*; D012132:Respiratory Muscles / Q000503:physiopathology; D014939:Work of Breathing
keywords: Assist Control Ventilation; Bronchopulmonary Dypslasia; Neonate; Prematurity; Proportional Assist Ventilation