title: [Threshold value of f/Vt index for predicting successful weaning from mechanical ventilation in active smokers].
abstract: BACKGROUND
  Mechanical ventilation (MV) is used in 60-70 % of patients admitted to the intensive care unit (ICU). An f/Vt threshold value of 105 is a predictor of successful weaning from mechanical ventilation (WMV) in patients with asthma, cardiac surgery, pneumonia, sepsis, neurocritical, etc. However, there are no reports about the usefulness of the f/Vt value to predict successful WMV in patients with active smoking (AS). The purpose of this paper is to identify a threshold value for f/Vt to predict successful WMV in patients with AS.
  
  
  METHODS
  Prospectively, 85 patients with AS and MV >24 hours admitted to de ICU were included. Demographic and clinical data were registered. The f/Vt value was measured with a Wright's spirometer, and the sensibility, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated to predict a successful WMV. A p value <0.05 was considered statistically significant.
  
  
  RESULTS
  The average of f/Vt was 68.69. Successful WMV was of 75.3 %. An f/Vt threshold value of 79.5 had sensibility of 76 %, specificity of 61 %, PPV of 85 %, and NPV of 46 % to predict successful WMV in this group of patients.
  
  
  CONCLUSIONS
  An f/Vt threshold value of 79.5 is useful to predict successful WMV in patients with AS.
authors.affiliation: Unidad de Cuidados Intensivos, Hospital de Especialidades, Centro Médico Nacional La Raza, Instituto Mexicano del Seguro Social, Ciudad de México, México. rommeljesus@hotmail.com.
authors.forename: Rommel Jesús
authors.initials: RJ
authors.lastname: Rivas-Salazar
authors.forename: José Ángel
authors.initials: JÁ
authors.lastname: Baltazar-Torres
authors.forename: Perla Cristina
authors.initials: PC
authors.lastname: Arvizu-Tachiquín
authors.forename: Israel
authors.initials: I
authors.lastname: Moreno-López
authors.forename: Sergio
authors.initials: S
authors.lastname: Zamora-Varela
authors.forename: Abraham Antonio
authors.initials: AA
authors.lastname: Cano-Oviedo
authors.forename: Alejandro
authors.initials: A
authors.lastname: Esquivel-Chávez
authors.forename: Luis Alejandro
authors.initials: LA
authors.lastname: Sánchez-Hurtado
mesh_terms: D000328:Adult; D000368:Aged; D003422:Critical Care; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011446:Prospective Studies; D012123:Pulmonary Ventilation; D012680:Sensitivity and Specificity; D012907:Smoking; D013147:Spirometry; D015300:Ventilator Weaning / Q000379:methods*
keywords: Artificial respiration; Mechanical ventilators; Respiratory insufficiency; Smoking