title: Serial measurements of f/VT can predict extubation failure in patients with f/VT < or = 105?
abstract: OBJECTIVE
  To evaluate is serial measurements of respiratory rate (frequency to tidal volume, f/VT) may predict extubation failure (EF) from mechanical ventilation in patients following a successful spontaneous breathing trial (SBT) with first measurement of f/V(T) < or = 105.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  Two medical-surgical intensive care units.
  
  
  METHODS
  Seventy-three patients ventilated for more than 48 hours after successful SBT were extubated and followed up for postextubation respiratory distress during 48 hours.
  
  
  RESULTS
  Extubation failure occurred in 16 (21.9%) of 73 patients. Factors such as age, sex, Apache II score, days on mechanical ventilation, respiratory failure cause, and hemodynamic or ventilatory parameters did not predict EF. Patients were evaluated during 120 minutes of SBT, and f/V(T) was measured at the 1st minute (f/V(T-1)), 30th minute (f/V(T-30)), and 120th minute (f/V(T-120)). The f/V(T-30) increased as compared with f/V(T-1) (79 +/- 24 vs 68 +/- 30, P = .01) but did not differ from f/V(T-120) (79 +/- 44 vs 81 +/- 42, P = .79). The f/V(T-1) was lower in successful extubation (ES) as compared with EF patients (62 +/- 29 vs 82 +/- 15, P = .01), and this difference was unchanged during the trial (f/V(T-30): ES [63 +/- 22] vs EF [85 +/- 24], P = .02; and f/V(T-120): ES [65 +/- 26] vs EF [88 +/- 20], P = .01)].
  
  
  CONCLUSIONS
  Serial f/V(T) measurements during 120 minutes of SBT were unable to detect EF in patients following a successful SBT with initial f/V(T) lower than 105.
authors.affiliation: Medical Physician of Central-ICU of Santa Casa Hospital, Porto Alegre, Brasil. cassiano.rush@terra.com.br
authors.forename: Cassiano
authors.initials: C
authors.lastname: Teixeira
authors.forename: Paulo José
authors.initials: PJ
authors.lastname: Zimermann Teixeira
authors.forename: Jorge Amilton
authors.initials: JA
authors.lastname: Hohër
authors.forename: Patrícia Pickersgill
authors.initials: PP
authors.lastname: de Leon
authors.forename: Sérgio Fernando Monteiro
authors.initials: SF
authors.lastname: Brodt
authors.forename: José
authors.initials: J
authors.lastname: da Siva Moreira
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D007442:Intubation, Intratracheal / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D013990:Tidal Volume; D017211:Treatment Failure; D015300:Ventilator Weaning / Q000379:methods*