[A pilot study of diaphragmatic function evaluated as predictors of weaning in chronic obstructive pulmonary disease patients].

Objective: To evaluate the predictive performance of neuro-mechanical coupling (NMC) and neuro-ventilatory coupling (NVC) in the weaning outcome in patients with chronic obstructive pulmonary disease (COPD).

Methods: Sixteen patients were enrolled when the criteria for their first spontaneous breathing trial (SBT) was met. A 30-minute SBT was attempted, with the measurement of electrical activity of the diaphragm (Edi), NMC, NVC, NVC × NMC, index of rapid shallow breathing (f/Vt), airway occlusion pressure (P(0.1)) and f/Vt × P(0.1) at 0, 5 and 30 min. The receiver operating characteristic (ROC) curve was calculated to evaluate the predictive performance of each index.

Results: Successful weaning (S group) was observed in 6 patients while weaning failure (F group) in 10 patients. (1) The predictive capacity of Edi: at 30 min of SBT, Edi showed higher values in the F group (P < 0.05), the area under the ROC curves (AUC) was 0.817(P < 0.05). (2) The predictive capacity of NVC and NMC: at 5, 30 min of SBT, NVC and NMC showed higher values in the S group (P < 0.05); at 30 min of SBT NVC presented the largest AUC than any other time of SBT (0.822, P < 0.05), while the AUC of NMC was 0.800(P > 0.05). (3) The predictive capacity of NVC × NMC: at 30 min of SBT, the AUC of NVC × NMC was larger than NVC (0.864, P < 0.05), showing greater sensitivity (100.0%) and specificity (83.3%). (4) The predictive capacity of f/Vt and P(0.1): f/Vt and f/Vt × P(0.1) presented poor predictive performance in the failed patients.

Conclusions: Edi, NVC and NVC × NMC were good predictor for the weaning outcome in patients with COPD.