title: Voluntary is better than involuntary cough peak flow for predicting re-intubation after scheduled extubation in cooperative subjects.
abstract: BACKGROUND
  In this study, we compared the predictive accuracy of voluntary cough peak flow (V-CPF) and involuntary cough peak flow (IV-CPF) for re-intubation in mechanically ventilated subjects.
  
  
  METHODS
  Endotracheally intubated patients who passed a spontaneous breathing trial and assessment of readiness for extubation were enrolled. Before extubation, V-CPF and IV-CPF were measured. Re-intubation was recorded at 72 h after extubation.
  
  
  RESULTS
  A total of 115 extubations in 106 cooperative subjects (including 9 subjects with second extubation) and 5 extubations in 5 uncooperative subjects were recorded. At 72 h, 20 (17.4%) and 1 (25%) instances of re-intubation occurred in cooperative and uncooperative subjects, respectively. In cooperative subjects, those who had been successfully extubated had higher V-CPF than re-intubated subjects (81.3 ± 41.4 vs 51.3 ± 31.7, P = .003). However, rates were not significantly different with IV-CPF (70.9 ± 39.8 vs 55.7 ± 37.9, P = .121). Areas under the curve of the receiver operating characteristic in V-CPF and IV-CPF were 0.743 ± 0.057 and 0.632 ± 0.069 (P < .001 and P = .058, respectively, compared with area under the curve = 0.5). V-CPF had higher predictive accuracy for re-intubation than IV-CPF (P = .034). In subjects with a lower quartile and third quartile V-CPF (≤ 43.2 L/min and 43.2-68.4 L/min, respectively), V-CPF was similar to IV-CPF. However, in second quartile and upper quartile V-CPF (68.4-99.0 L/min and > 99.0 L/min, respectively), V-CPF was higher than IV-CPF (82.1 ± 9.6 vs 66.6 ± 19.5 L/min, P < .001; 135.5 ± 29.8 vs 116.2 ± 38.2 L/min, P = .006, respectively). Overall, V-CPF was higher than IV-CPF (76.0 ± 41.4 vs 68.2 ± 39.7, P = .003). In uncooperative subjects, the IV-CPF was higher than V-CPF (40.2 ± 10.2 vs 79.2 ± 29.0, P = .042).
  
  
  CONCLUSIONS
  V-CPF is noninvasive. It is much more accurate than IV-CPF as a predictor of re-intubation in cooperative patients because the IV-CPF may underestimate cough strength in patients with high V-CPF. However, it is unclear which is optimal for use in uncooperative patients.
authors.affiliation: Department of Respiratory Medicine, First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China. duanjun412589@163.com.
authors.forename: Jun
authors.initials: J
authors.lastname: Duan
authors.affiliation: Department of Respiratory Medicine, First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China.
authors.forename: Jinhua
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Respiratory Medicine, First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China.
authors.forename: Meiling
authors.initials: M
authors.lastname: Xiao
authors.affiliation: Department of Respiratory Medicine, First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China.
authors.forename: Xiangmei
authors.initials: X
authors.lastname: Yang
authors.affiliation: Department of Respiratory Medicine, First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China.
authors.forename: Jinxing
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Respiratory Medicine, First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China.
authors.forename: Lintong
authors.initials: L
authors.lastname: Zhou
mesh_terms: D000368:Aged; D060666:Airway Extubation / Q000379:methods*; D003371:Cough / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal / Q000379:methods*; D008297:Male; D010366:Peak Expiratory Flow Rate / Q000502:physiology*; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve; D012121:Respiration, Artificial; D015300:Ventilator Weaning / Q000379:methods*
keywords: cough peak flow; extubation; re-intubation; spontaneous breathing trial; tracheotomy