title: Variability of respiratory parameters and extubation readiness in ventilated neonates.
abstract: BACKGROUND
  A spontaneous breathing trial (SBT) has been used to guide suitability of extubation in VLBW infants. Respiratory variability (RV) has been used to assess extubation readiness in adults but was never investigated in preterms. The combination of a SBT and RV may further improve prediction of successful extubation.
  
  
  METHODS
  Using data previously collected during the SBT, the following respiratory variables were analysed: inspiratory time (T(I)), expiratory time (T(E)), T(I)/total breath time, tidal volume (V(T)) and mean inspiratory flow (V(T)/T(I)). RV was quantified using time-domain analysis for each respiratory variable and expressed as a variability index (VI). The sensitivity, specificity, positive and negative predictive values (PPV and NPV) of the SBT, each VI and combined SBT+VI were calculated. Extubation failure was defined as need of re-intubation within 72 h.
  
  
  RESULTS
  A total of 44 infants were included. Successfully (n=36) and unsuccessfully (n=8) extubated infants had similar baseline characteristics and number of breaths analysed. VI for V(T)/T(I)was significantly decreased in the failure group. The combination of the SBT and VI of either T(I)or V(T)were the most accurate predictors of successful extubation with a sensitivity of 100% and specificity of 75% and a PPV and NPV for extubation success of 95% and 100%, respectively.
  
  
  CONCLUSIONS
  A significant decrease in V(T)/T(I)variability occurred in infants requiring re-intubation. The combination of a SBT failure and decreased variability in T(I)or V(T)was highly predictive of failure. This combination is promising but requires prospective evaluation in a larger population.
authors.affiliation: Department of Neonatology, McGill University, Montreal, Canada.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Kaczmarek
authors.forename: C Omar Farouk
authors.initials: CO
authors.lastname: Kamlin
authors.forename: Colin J
authors.initials: CJ
authors.lastname: Morley
authors.forename: Peter G
authors.initials: PG
authors.lastname: Davis
authors.forename: Guilherme M
authors.initials: GM
authors.lastname: Sant'anna
mesh_terms: D060666:Airway Extubation; D006801:Humans; D007231:Infant, Newborn; D019102:Infant, Very Low Birth Weight; D012121:Respiration, Artificial; D012129:Respiratory Function Tests; D015656:Respiratory Mechanics; D012680:Sensitivity and Specificity; D013990:Tidal Volume; D015300:Ventilator Weaning