Correction: Non-invasive ventilation with pursed lips breathing mode for patients with COPD and hypercapnic respiratory failure: A retrospective analysis

In Fig 4, panel B does not appear. In Fig 5, panels B and C do not appear. Please see the correct Figs 4 and 5 here.

Fig 4. pCO₂ values at baseline and follow-up and correlation of ΔpCO₂ with ΔIPAP.

A. Each line represents an early morning pCO₂ value for a single patient at baseline and follow up. B. Scatter plot illustrating the correlation of ΔpCO₂ (pCO₂ at follow-up—pCO₂ at baseline) and ΔIPAP (IPAP at follow-up—IPAP at baseline).

Fig 5. 6MWT distances at baseline and follow-up and correlations of Δ6MWT with ΔIPAP and ΔpCO₂.

A. Walking distances in the 6MWT at baseline and at follow-up. Each line represents a patient. B. Scatter plot illustrating the correlation of Δ6MWT (6MWT at follow-up– 6MWT at baseline) and ΔIPAP (IPAP at follow-up—IPAP at baseline). C. Scatter plot illustrating the correlation of Δ6MWT (6MWT at follow.up– 6MWT at baseline) and ΔpCO₂ (pCO₂ at follow-up—pCO₂ at baseline).