Complex ventilation problems with no simple solution

Daoud and Franck in this edition of the journal proffer an eloquent disquisition on alveolar compliance and resistance and describe ways in which we could make estimates of the effect of ventilation changes, using esophageal balloon manometry measure the trans alveolar pressure, and estimating the alveolar tidal volume using volumetric capnometry. 10 The article like the subject it addresses is complex and requires an active rather than passive read. It outlines the concepts clearly and highlights the need for accurate and exacting measurement. Complicating this is the need to provide simultaneous diaphragmatic and alveolar protective ventilation, which further complicates modelling of controlled ventilation strategies. 11 It remains something to be addressed in the future.