Utility of uric acid as a risk marker of extubation success in chronic obstructive pulmonary disease.

BACKGROUND: The objective of this observational study was to determine whether there is an association between extubation success and uric acid in chronic obstructive pulmonary disease patients with mechanical ventilation admitted to the intensive care units, and identify the risk markers for extubation success in COPD patients with mechanical ventilation.

METHODS: Consecutive COPD patients with intubation were screened at baseline. The study included patients on mechanical ventilation (MV) for over 12 hours and who, in the process of weaning, were subjected to low-level pressure support. Exclusion criteria were age under 18 years, ventilation via tracheotomy, and patients failing to cooperate for different reasons. The final study population consisted of 106 patients. Demographic, clinical, laboratory, and mechanical ventilation parameters were carefully recorded. Logistic regression was used for the multivariate analysis of independent risk factors.

RESULTS: Uric acid on admission, duration of mechanical ventilation, pressure support ventilation, and APACHE II score on admission were significantly higher in COPD patients with extubation failure than in those with extubation success (p < 0.05), but lower tidal volume before weaning was observed in COPD patients with extubation failure. Among these patients, multiple logistic analyses indicated the independent risk factors for extubation success in the COPD subjects included serum uric acid level, APACHE II score on admission, and duration of mechanical ventilation. The diagnosis analysis showed that higher uric acid level and APACHE II score on admission and longer duration of mechanical ventilation had a significant ability to reflect extubation success in the COPD patients with respiratory failure.

CONCLUSIONS: The novel finding of this study is that the extubation failure in COPD patients with respiratory failure is strongly related to serum uric acid level, APACHE II score on admission, and duration of mechanical ventilation. These results might be helpful for selecting the best time to remove the tracheal intubation and improving extubation success rate in COPD patients with respiratory failure.