title: Prediction of infant extubation outcomes using the tension-time index.
abstract: OBJECTIVE
  The tension-time index of the diaphragm (TTdi) is a composite assessment of the load on and the capacity of the diaphragm. TTmus is a non-invasive tension-time index of the respiratory muscles. Our aim was to determine whether TTdi or TTmus predicted extubation outcome and performed better than respiratory muscle strength (Pimax, Pdimax), respiratory drive (P0.1) and work of breathing (transdiaphragmatic pressure-time product (PTPdi)) or routinely available clinical data.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Tertiary neonatal intensive care unit.
  
  
  METHODS
  Sixty infants, median gestation age 35 (range 23-42) weeks and postnatal age of 55 (range 1-115) days.
  
  
  METHODS
  Airway occlusions were performed to measure Pimax, Pdimax and P0.1. TTdi and PTPdi were derived from measurements of transdiaphragmatic pressure. TTmus was derived from airway pressure measurements. Measurements were made within 6 h of extubation.
  
  
  METHODS
  Extubation failure defined as reintubation within 48 h of extubation.
  
  
  RESULTS
  Twelve infants failed extubation. The infants who failed extubation were significantly more immature (medians 25 vs 37 weeks) and of greater postnatal age (23 vs 5 days) and had higher TTdi (0.15 vs 0.04) and TTmus (0.17 vs 0.08). TTdi and TTmus were only significantly better predictors than the peak inflation pressure immediately prior to extubation and did not perform significantly better than gestational age or birth weight.
  
  
  CONCLUSIONS
  Assessment of TTdi and TTmus cannot be recommended for use in routine clinical practice.
authors.affiliation: Division of Asthma, Allergy and Lung Biology, MRC-Asthma UK Centre in Allergic Mechanisms of Asthma, King's College London, London, UK.
authors.forename: Prashanth
authors.initials: P
authors.lastname: Bhat
authors.affiliation: Division of Health and Social Care Research, King's College London, London, UK National Institute for Health Research (NIHR) Biomedical Research Centre, 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-Asthma UK Centre in Allergic Mechanisms of Asthma, King's College London, London, UK.
authors.forename: Gerrard F
authors.initials: GF
authors.lastname: Rafferty
authors.affiliation: Division of Asthma, Allergy and Lung Biology, MRC-Asthma UK Centre in Allergic Mechanisms of 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-Asthma UK Centre in Allergic Mechanisms of Asthma, King's College London, London, UK National Institute for Health Research (NIHR) Biomedical Research Centre, 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: D060666:Airway Extubation; D003964:Diaphragm / Q000502:physiology*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D053580:Muscle Strength / Q000502:physiology; D011446:Prospective Studies; D012132:Respiratory Muscles / Q000502:physiology*; D014939:Work of Breathing
keywords: diaphragm; extubation; mechanical ventilation; respiratory muscles