Role of assessment of the diaphragm by ultrasound during weaning from mechanical ventilation in patients with chronic obstructive pulmonary disease

Abstract

Background Diaphragmatic rapid shallow breathing index (D-RSBI) is a new promising tool to predict weaning outcome. The D-RSBI is the ratio between respiratory rate (RR) and the ultrasonographic evaluation of diaphragmatic displacement (DD). Its accuracy in predicting weaning failure, in ready-to-wean mechanically ventilated (MV) patients with chronic obstructive pulmonary disease (COPD), needs to be evaluated. Aim To assess diaphragm using ultrasound during weaning from MV in patients with COPD and to compare the new D-RSBI with traditional RSBI. Patients and methods A prospective observational study was carried out on MV patients with COPD who were ready to wean. During spontaneous breathing trial, evaluation of the right hemi-DD and diaphragmatic thickness by using M-mode ultrasonography was done. Then calculation of D-RSBI (RR/DD), and RSBI (RR/tidal volume) was carried out simultaneously. Outcomes of the weaning trials were recorded. Receiver operating characteristic curves were used to evaluate the diagnostic accuracy of D-RSBI and RSBI. Results A total of 104 patients with acute exacerbation COPD who were ready to perform an spontaneous breathing trial from MV were included. Overall, 86 (82.7%) were successfully liberated from MV, and 18 (17.3%) patients had failure of weaning. The sensitivity and specificity of DD were 72.2 and 93.0%, respectively. The sensitivity and specificity of RSBI were 77.8 and 70.9%, respectively. However, the sensitivity and specificity of D-RSBI were 83.3 and 90.7%, respectively. Conclusion D-RSBI (RR/DD) is superior than the traditional RSBI (RR/tidal volume) in predicting weaning outcome in patients with acute exacerbation COPD.