The undesirable formation of a semi-crystalline phase of dipalmitoylphosphatidylcholine (DPPC) during compression of a monolayer of the phospholipids (mimicking the expiration phase of the respiratory cycle) can be prevented by contacting the monolayer with perfluorooctylethane (C₈ F₁₇ CH₂ CH₃ , PFOE). Moreover, the perfluorocarbon (PFC) can dissolve the DPPC liquid-condensed domains that are already formed, and can help re-spread the DPPC molecules at the air/water interface. Criteria are set for the selection of appropriate PFCs. Perfluorooctyl bromide (C₈ F₁₇ Br) and PFOE effectively hinder the adsorption of bovine serum albumin (BSA, solubilized in the sub-phase) upon re-expansion of the DPPC monolayer (inspiration). As a consequence, the PFCs reduce significantly the deleterious delipidating effect of BSA towards the DPPC monolayer. We suggest that combinations of DPPC and a PFC gas may be useful in the treatment of lung conditions, resulting either from a lack of native lung surfactant, such as in the neonate respiratory distress syndrome (NRDS), or from a deterioration of the native lung surfactant function due to plasma proteins, such as in the acute respiratory distress syndrome (ARDS) in adults.