title: Brain natriuretic peptide as a predictor of weaning from mechanical ventilation in patients with respiratory illness.
abstract: BACKGROUND
  Cardiovascular dysfunction has been reported as an important mechanism of weaning failure. Brain natriuretic peptide (BNP) is a sensitive and specific marker for cardiovascular dysfunction.
  
  
  OBJECTIVE
  To determine the value of BNP levels measured at initiation and end of a 2h spontaneous breathing trial (SBT) as a predictor of successful weaning of mechanical ventilation in patients with respiratory illness.
  
  
  METHODS
  Thirty consecutive patients ready for weaning were prospectively enrolled in this cross-sectional analytic study over a 6-month period. All patients had been on spontaneous mode of weaning for at least 2h. Tidal volume, respiratory rate, rapid shallow breathing index (RSBI), minute ventilation and PaO2/FiO2 were observed at initiation of SBT. BNP was measured at the initiation (BNP1) and at the end of SBT (BNP2). Weaning failure is defined as either the failure of SBT or the need for reintubation within 48 h following extubation.
  
  
  RESULTS
  Out of the 30 included patients, 14 (46.6%) patients had failed weaning. PaCO2 and BNP2 were significantly higher in the patients with failed weaning as compared to those with successful weaning (P = 0.025, P = 0.031 respectively). However, BNP1 levels were not statistically significant between the 2 groups (P = 0.722). On multiple regression analysis, BNP% (percent change in the BNP level during the 2-h SBT) was the only predictor of weaning success. As compared to other weaning parameters, BNP% ≤ 14.9 had the best sensitivity, specificity, positive and negative predictive value.
  
  
  CONCLUSIONS
  Measuring the percentage change in the BNP level during a SBT may be a good predictor of weaning success from mechanical ventilation in respiratory patients.
authors.affiliation: Chest Department, Faculty of Medicine, Assiut University Hospital, Egypt. Electronic address: shereen_hssn@yahoo.com.
authors.forename: Shereen
authors.initials: S
authors.lastname: Farghaly
authors.affiliation: Anesthesiology Department, South Egypt Cancer Institute, Assiut University Hospital, Egypt. Electronic address: dr_mostafagalal@yahoo.com.
authors.forename: Mostafa
authors.initials: M
authors.lastname: Galal
authors.affiliation: Chest Department, Faculty of Medicine, Assiut University Hospital, Egypt. Electronic address: aabdelazeem@yahoo.com.
authors.forename: Ali A
authors.initials: AA
authors.lastname: Hasan
authors.affiliation: Clinical Pathology Department, Faculty of Medicine, Assiut University Hospital, Egypt. Electronic address: asmaa_nafadyhn@yahoo.com.
authors.forename: Asmaa
authors.initials: A
authors.lastname: Nafady
mesh_terms: D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007362:Intensive Care Units / Q000706:statistics & numerical data; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012140:Respiratory Tract Diseases / Q000628:therapy*; D017211:Treatment Failure; D015300:Ventilator Weaning
chemical_list: D015415:Biomarkers; D020097:Natriuretic Peptide, Brain
keywords: BNP; Mechanical ventilation; Spontaneous breathing trial; Weaning