title: Position and ventilatory response to added dead space in prematurely born infants.
abstract: OBJECTIVE
  Prematurely born infants are at increased risk of sudden infant death syndrome (SIDS) if slept prone.
  
  
  OBJECTIVE
  Prematurely born infants would have an impaired response to an added dead space and lower respiratory muscle strength in the prone compared to the supine position.
  
  
  METHODS
  Prospective study. PATIENT-SUBJECT SELECTION: Twenty-five infants, median gestational age of 30 (range 26-32) weeks.
  
  
  METHODS
  The infants were studied supine and prone at a median of 36 weeks postmenstrual age. Breath by breath minute volume was measured at baseline and after a dead space was incorporated into the breathing circuit; the time constant of the response was calculated. The maximum inspiratory occlusion pressure generated (MIOP) and the pressure generated over the first 100 msec (P(0.1)) during airway occlusion were assessed.
  
  
  RESULTS
  The median time constant was longer (26 (range 8-106) sec vs. 22 (range 6-92) sec (P = 0.045)) and the median MIOP (P = 0.001) and P(0.1) (P = 0.003) were lower in the prone compared to the supine position.
  
  
  CONCLUSIONS
  Prematurely born infants have a dampened response to tube breathing and reduced respiratory muscle strength in the prone compared to the supine position, which may contribute to their increased vulnerability to SIDS in the prone position.
authors.affiliation: King's College London, MRC-Asthma Centre, Division of Asthma, Allergy and Lung Biology, London, UK.
authors.forename: Harish
authors.initials: H
authors.lastname: Rao
authors.forename: Tolulope
authors.initials: T
authors.lastname: Saiki
authors.forename: Francesca
authors.initials: F
authors.lastname: Landolfo
authors.forename: Adam P R
authors.initials: AP
authors.lastname: Smith
authors.forename: Simon
authors.initials: S
authors.lastname: Hannam
authors.forename: Gerrard F
authors.initials: GF
authors.lastname: Rafferty
authors.forename: Anthony D
authors.initials: AD
authors.lastname: Milner
authors.forename: Anne
authors.initials: A
authors.lastname: Greenough
mesh_terms: D000222:Adaptation, Physiological; D004867:Equipment Design; D005865:Gestational Age; D006801:Humans; D007230:Infant, Low Birth Weight / Q000502:physiology*; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D053580:Muscle Strength; D016684:Prone Position; D011446:Prospective Studies; D012126:Respiratory Dead Space; D012129:Respiratory Function Tests / Q000295:instrumentation / Q000379:methods*; D012132:Respiratory Muscles / Q000502:physiology*; D016683:Supine Position