title: Electrical impedance tomography to evaluate air distribution prior to extubation in very-low-birth-weight infants: a feasibility study.
abstract: OBJECTIVE
  Nasal continuous positive airway pressure is used as a standard of care after extubation in very-low-birth-weight infants. A pressure of 5 cmH2O is usually applied regardless of individual differences in lung compliance. Current methods for evaluation of lung compliance and air distribution in the lungs are thus imprecise for preterm infants. This study used electrical impedance tomography to determine the feasibility of evaluating the positive end-expiratory pressure level associated with a more homogeneous air distribution within the lungs before extubation.
  
  
  METHODS
  Ventilation homogeneity was defined by electrical impedance tomography as the ratio of ventilation between dependent and non-dependent lung areas. The best ventilation homogeneity was achieved when this ratio was equal to 1. Just before extubation, decremental expiratory pressure levels were applied (8, 7, 6 and 5 cmH(2)0; 3 minutes each step), and the pressure that determined the best ventilation homogeneity was defined as the best positive end-expiratory pressure.
  
  
  RESULTS
  The best positive end-expiratory pressure value was 6.3 ± 1.1 cmH(2)0, and the mean continuous positive airway pressure applied after extubation was 5.2 ± 0.4 cmH(2)0 (p = 0.002). The extubation failure rate was 21.4%. X-Ray and blood gases after extubation were also checked.
  
  
  CONCLUSIONS
  This study demonstrates that electrical impedance tomography can be safely and successfully used in patients ready for extubation to suggest the best ventilation homogeneity, which is influenced by the level of expiratory pressure applied. In this feasibility study, the best lung compliance was found with pressure levels higher than the continuous positive airway pressure levels that are usually applied for routine extubation.
authors: Departamento Materno-infantil, Hospital Israelita Albert Einstein, São Paulo, SP, Brazil.
authors: Felipe de Souza
authors: Fde S
authors: Rossi
authors: Ana Cristina Zanon
authors: AC
authors: Yagui
authors: Luciana Branco
authors: LB
authors: Haddad
authors: Alice D'Agostini
authors: AD
authors: Deutsch
authors: Celso Moura
authors: CM
authors: Rebello
mesh_terms: D060666:Airway Extubation / Q000379:methods*; D017097:Electric Impedance; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D019102:Infant, Very Low Birth Weight / Q000502:physiology*; D008170:Lung Compliance / Q000502:physiology; D008297:Male; D011175:Positive-Pressure Respiration / Q000379:methods*; D012016:Reference Values; D015203:Reproducibility of Results; D014054:Tomography / Q000379:methods*; D016896:Treatment Outcome
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