Objective: To investigate the correlation between diaphragmatic-rapid shallow breathing index (D-RSBI) and lung ultrasound score (LUS) in elderly patients with mechanical ventilation and its predictive value for weaning results.
Methods: A retrospective study was conducted. The clinical data of elderly patients (age > 60 years old) with invasive positive pressure ventilation (IPPV) admitted to the department of intensive care unit (ICU) of the First Affiliated Hospital of Jinzhou Medical University from January 2021 to June 2022 were enrolled. According to the outcome of withdrawal, the patients were divided into successful and failed groups. The differences in gender, age, acute physiology and chronic health evaluation II (APACHE II), D-RSBI and LUS before weaning and extubation were compared between the two groups. Pearson correlation was used to analyze the correlation between D-RSBI and LUS. The predictive value of D-RSBI and LUS on weaning results of elderly patients with IPPV was analyzed by receiver operator characteristic curve (ROC curve).
Results: A total of 398 elderly patients with IPPV were enrolled, including 300 successful weaning patients and 98 failed weaning patients. There were no significant differences in gender and age between the failed group and successful group [male: 55.1% (54/98) vs. 59.0% (177/300), age (years old): 67.02±5.03 vs. 66.96±4.99, both P > 0.05]. APACHE II score in the failed group was significantly higher than that in the successful group (17.09±3.30 vs. 16.06±3.81, P < 0.05), and the D-RSBI and LUS score before extubation were significantly higher than those in the successful group [D-RSBI (time×min-1×mm-1): 2.19±0.33 vs. 1.60±0.22, LUS: 17.30±3.04 vs. 11.97±3.20, both P < 0.01]. All patients showed a significant positive correlation between D-RSBI and LUS score (r = 0.406, P = 0.000). ROC curve analysis showed that the area under the curve (AUC) of D-RSBI for predicting weaning outcomes in elderly IPPV patients was 0.920, with a 95% confidence interval (95%CI) of 0.881-0.958 and P = 0.000. When the cut-off value was 1.85 times×min-1×mm-1, the sensitivity was 88.7% and the specificity was 86.7%. The AUC of LUS score for predicting weaning outcome in elderly IPPV patients was 0.875, with a 95%CI of 0.839-0.912 and P = 0.000. When the cut-off value was 14.50, the sensitivity was 75.7% and the specificity was 84.7%.
Conclusions: There is a significant correlation between D-RSBI and LUS score in elderly mechanically ventilated patients, both of them can predict weaning outcome in elderly patients with mechanical ventilation.