PURPOSE: Adequate diaphragm contraction is essential for successful weaning and extubation from mechanical ventilation (MV). We compared the degree of diaphragm thickening during inspiration to the Rapid Shallow Breathing Index (RSBI) in patients undergoing extubation.
METHODS: We used B-mode Ultrasound (US) to measure inspiratory diaphragm thickening (∆tdi) in patients undergoing weaning trials with pressure support ventilation. RSBI and ∆tdi were measured simultaneously within half hour of extubation. Inspiratory diaphragm thickening was calculated as the difference between diaphragm thickness at end-inspiration and end-expiration (tdiFRC) and normalized to tdiFRC (∆tdi %). Patients were followed for 24 hours after extubation to determine extubation success or failure. The predictive value of ∆tdi % was compared to that for RSBI.
RESULTS: Sixteen consecutive patients were included in the study (6 males). The age was 74.1 ± 3.2 years (mean ± SEM). Fourteen patients had a successful extubation while 2 had to be reintubated. The RSBI was 52.1 ± 4.4 vs 67.5 and ∆tdi % was 44.7% ± 12 vs 16.7% in patients with successful and failed extubation respectively.
CONCLUSION: Diaphragm thickening was reduced in patients who failed extubation despite having an acceptable RSBI for extubation.
CLINICAL IMPLICATIONS: Diaphragm thickening may prove to be a non-invasive effort-independent predictor of weaning success or failure that can be used in conjunction with the RSBI.
DISCLOSURE: Yaser Abu El-Sameed, None.