Predictive value of lung ultrasound score on weaning outcome in patients with intro-abdominal infection undergoing mechanical ventilation / 中华危重病急救医学

ABSTRACT

Objective:To evaluate the value of lung ultrasound score (LUS) on predicting weaning outcome in patients with intro-abdominal infection (IAI) undergoing mechanical ventilation.Methods:Patients with IAI undergoing mechanical ventilation admitted to Research Institute of General Surgery of East War Zone Hospital and intensive care unit (ICU) of the First People's Hospital of Lianyungang from January to December in 2018 were included. The patients who satisfied weaning criteria were enrolled in the weaning process, which included spontaneous breathing trial (SBT) and extubation. They were divided into SBT success group and SBT failure group according to whether passed 120-minute SBT or not. LUS scores before and after SBT were compared between the two groups. The patients in the SBT success group were extubated, and they were divided into successful extubation group and failed extubation group for sub-group analysis according to whether re-intubation was needed in 48 hours after extubation. LUS score before extubation (at the end of SBT) and 48 hours after extubation (48 hours after extubation in the successful extubation group or before re-intubation in the failed extubation group) were compared. The receiver operating characteristic (ROC) curve was drawn to evaluate the predictive value of LUS score before SBT for SBT failure and LUS score before extubation for the failure.Results:A total of 76 patients with IAI undergoing mechanical ventilation were included. Twenty-three patients had duration of mechanical ventilation less than 48 hours, severe chronic obstructive pulmonary disease (COPD), tracheotomy or automatic discharge were excluded, and 53 patients were enrolled. SBT was failed in 9 patients, and successfully performed in 44 patients, of whom 23 patients with successful extubation, and 21 with failed extubation. The LUS scores before and after SBT in the SBT failure group were significantly higher than those in the SBT success group (before SBT 13.22±1.99 vs. 10.79±1.64, t = -3.911, P = 0.000; after SBT 19.00±1.12 vs. 13.41±1.86, t = -8.665, P = 0.000). ROC curve analysis showed that the area under ROC curve (AUC) of LUS score before SBT for predicting SBT failure was 0.82 [95% confidence interval (95% CI) was 0.67-0.98, P = 0.002]. When the optimum cut-off value was 12.5, the sensitivity was 66.7%, and the specificity was 84.1%. Sub-group analysis showed that the LUS scores before and after extubation in the failed extubation group were significantly higher than those in the successful extubation group (before extubation 14.19±1.60 vs. 12.69±1.81, t = -2.881, P = 0.006; after extubation 16.42±1.59 vs. 12.78±1.54, t = -7.710, P = 0.000). ROC curve analysis showed that the AUC of LUS score before extubation for predicting the failure was 0.81 (95% CI was 0.69-0.92, P = 0.000). When the optimum cut-off value was 13.5, the sensitivity was 80.0%, and the specificity was 65.2%. Conclusion:LUS score can effectively predict SBT outcome, risk of re-intubation after extubation in patients with IAI undergoing mechanical ventilation.