A 60-year-old patient with a history of emphysema who failed to wean from mechanical ventilation seven days after right-unilateral lung transplantation, an elevation of the left hemi-diaphragm was noticed (Fig. 1). To evaluate respiratory muscle mechanics transdiaphragmatic pressure (Pdi) was monitored during pressure support, revealing insufficient respiratory muscle strength showed in Pdi and ΔPgas/ΔPes ratio (Fig. 2, upper panel); as well in calculate partitioning pressure-time product (PTP) (Fig. 3). A remarkable biphasic morphology of Pdi during the inspiration was observed (Fig. 2, bottom panel), explained by the negative intrathoracic pressure drags the paretic and subsequent twitch of the competent hemi-diaphragm (arrows). This biphasic morphology of Pdi can distinguish hemi-diaphragm paralysis from other diaphragm dysfunction. The patient needs home ventilation.

Figure 1

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Figure 2

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Figure 3

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