Background: Mechanical ventilation (MV) can cause progressive thinning of diaphragm muscle and hence progressive decline in diaphragmatic function. We aimed to assess the rate at which diaphragm thickness (tdi) changed during MV and its effect on weaning outcome using transthoracic ultrasound (TUS) evaluation in COPD patients.
Methods: Thirty mechanically ventilated COPD patients were enrolled in this cohort study. Baseline Tdi were recorded within 24 hrs of MV after stoppage of sedation using TUS. The subsequent measurements were recorded at the 3rd day, 5th day and 7th day of MV and at time of initiation of weaning.
Results: There was a significant drop in tdi at end expiration and at end inspiration by about 27.2% and 17%, 35.5% and 18.5% at 3rd and 5th day of MV respectively compared to baseline parameters. In the 10 patients who were still on ventilator till the 7th day, tdi were significantly lower compared to baseline recordings. Percentage of decline of tdi at end inspiration from baseline recordings was significantly higher in patients with difficult weaning than in those with simple weaning. The optimum cut off value of % of decline of tdi at end inspiration associated with difficult weaning was ≥ 10.6% giving 88.9% sensitivity and 83.3% specificity.
Conclusion: MV is associated with gradual diaphragmatic atrophy which can be detected by TUS and could predict weaning outcome in mechanically ventilated COPD patients.