title: Physiological responses during a T-piece weaning trial with a deflated tube.
abstract: BACKGROUND
  T-piece trials and spontaneous breathing trials through the tracheostomy tube are often used as weaning techniques. They are usually performed with the cuff inflated, which may increase the inspiratory load and/or influence the tidal volume generated by the patient. We assessed diaphragmatic effort during T-piece trials with or without cuff inflation.
  
  
  METHODS
  Respiratory intensive care unit
  
  
  METHODS
  We measured breathing pattern, transdiaphragmatic pressure (Pdi), the pressure-time product of the diaphragm, per minute (PTPdi/min) and per breath (PTPdi/b), and lung mechanics (lung compliance and resistance) in 13 tracheotomized patients ready for a weaning trial. V(T) was recorded with respiratory inductive plethysmography (RIP-V(T)) or pneumotachography PT-V(T)). Patients completed two T-piece trials of 30[Symbol: see text]min each with or without the cuff inflated.
  
  
  RESULTS
  RIP-V(T) and PT-V(T) values were similar with the cuff inflated, but PT-V(T) significantly underestimated RIP-V(T) when the cuff was deflated, and therefore the RIP-V(T) was chosen as the reference method. The RIP-V(T) was significantly greater and the Pdi and PTPdi/min significantly lower when the cuff was deflated than when it was inflated. The efficiency of the diaphragm, calculated by the ratio of PTPdi/b over RIP-V(T), was also improved, while no changes were observed in lung mechanics.
  
  
  CONCLUSIONS
  Diaphragmatic effort is significantly lower during a T-piece trial with a deflated cuff than when the cuff is inflated, while RIP-V(T) is higher, so that the diaphragm's efficiency in generating tidal volume is also improved.
authors.affiliation: Respiratory Intensive Care Unit, Fondazione S. Maugeri, IRCCS, Istituto Scientifico di Pavia, Via Ferrata 8, 27100 Pavia, Italy.
authors.forename: Piero
authors.initials: P
authors.lastname: Ceriana
authors.forename: Annalisa
authors.initials: A
authors.lastname: Carlucci
authors.forename: Paolo
authors.initials: P
authors.lastname: Navalesi
authors.forename: Georgios
authors.initials: G
authors.lastname: Prinianakis
authors.forename: Francesco
authors.initials: F
authors.lastname: Fanfulla
authors.forename: Monica
authors.initials: M
authors.lastname: Delmastro
authors.forename: Stefano
authors.initials: S
authors.lastname: Nava
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010991:Plethysmography; D015656:Respiratory Mechanics; D018709:Statistics, Nonparametric; D014139:Tracheostomy; D015300:Ventilator Weaning / Q000295:instrumentation / Q000379:methods*; D014939:Work of Breathing