title: Work of breathing during SIMV with and without pressure support.
abstract: OBJECTIVE
  In a randomised trial, pressure support with synchronised intermittent mandatory ventilation (SIMV) compared to SIMV alone was associated with a significant reduction in supplementary oxygen duration. The hypothesis that the addition of pressure support to SIMV compared to SIMV alone would reduce the work of breathing was examined.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Perinatal service.
  
  
  METHODS
  20 infants, with a mean gestational age of 31 weeks, being weaned from mechanical ventilation were studied.
  
  
  METHODS
  1 h periods of SIMV and SIMV with pressure support at 50% of the difference between the peak inflating pressure and positive end expiratory pressures.
  
  
  METHODS
  The work of breathing was assessed by measurement of the transdiaphragmatic pressure time product (PTPdi).
  
  
  RESULTS
  The mean PTPdi on SIMV plus pressure support was 112 cm H(2)Oxs/min, approximately 20% lower than that on SIMV alone (141 cm H(2)Oxs/min) (p<0.001).
  
  
  CONCLUSIONS
  The addition of pressure support to SIMV reduces the work of breathing in infants being weaned from the ventilator.
authors.affiliation: Division of Asthma, Allergy and Lung Biology, School of Medicine, King's College London, London, UK.
authors.forename: D-S
authors.initials: DS
authors.lastname: Patel
authors.forename: G F
authors.initials: GF
authors.lastname: Rafferty
authors.forename: S
authors.initials: S
authors.lastname: Lee
authors.forename: S
authors.initials: S
authors.lastname: Hannam
authors.forename: A
authors.initials: A
authors.lastname: Greenough
mesh_terms: D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D015931:Intensive Care, Neonatal; D007385:Intermittent Positive-Pressure Ventilation / Q000379:methods*; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D011446:Prospective Studies; D012131:Respiratory Insufficiency / Q000503:physiopathology / Q000628:therapy*; D016896:Treatment Outcome; D014939:Work of Breathing / Q000502:physiology*