Pulmonary alveolar proteinosis (PAP) is a rare clinical syndrome characterized by the progressive accumulation of PAS-positive acellular surfactant in the alveolar spaces and in the terminal bronchioles, the alveolar architecture remaining usually well preserved [1]. The progressive endoalveolar surfactant engorgement leads to a worsening of dyspnoea, dry cough, high risk of opportunistic infections and eventually respiratory insufficiency, requiring whole lung lavage (WLL) as the gold standard therapy [2]. A single two-lung lavage has shown its efficacy in improving forced vital capacity (FVC), arterial oxygen tension (PaO2), carbon monoxide diffusing capacity (DLCO) and mean walking distance in the majority of patients, but in refractory cases multiple lavages are needed [3]. To the best of our knowledge, the assessment of respiratory mechanics has never been performed during a series of WLL. Thus to verify whether respiratory mechanical data could provide any helpful advice toward maintenance of repeated WLL, the measurement of respiratory system elastance and resistance was done in a patient with PAP who did not respond to a single WLL and required multiple WLLs. A 69-year-old man was admitted to our department owing to a severe exacerbation of an acquired form of PAP. The values of pulmonary function tests (PFT), gas exchange and 6-min walking test (6MWT), assessed several months before the clinical impairment, are reported in Table 1. Right before starting the procedure, the respiratory rate and gas exchange were evaluated on room air during spontaneous ventilation. The patient underwent bilateral WLL by anesthesia with fentanyl 3 lg/kg, propofol 2.5 mg/kg and cisatracurium 0.1 mg/kg; after placement of a left-sided double-lumen endotracheal tube. Anesthesia was maintained with a continuous infusion of propofol 0.1 mg/kg/min. The lavage was started in the lateral decubitus position, with tidal volumes of saline warmed to body temperature, both delivered and drained by gravity through a large-bore tubing system. Lavage was continued until the outflow fluid became definitely clear, which may take a total of 30–40 L saline for a single lung. The lavage of the second lung was performed with the patient in the opposite lateral decubitus position, using the same procedure [3]. A static pressure–volume (P–V) curve was performed under volume-controlled ventilation, and six different inflation volumes were used. After each inflation, a 4-s pause was allowed. Respiratory system elastance (Ers) was calculated as a median value along the whole range of the P–V curve. Respiratory system resistance (Rrs) was calculated at the same tidal volume and inspiratory flow. The patient showed a reduction in respiratory rate, but a worse oxygenation after the first lavage, and needed another four bilateral WLLs in the subsequent 6 months to reach a remission of the clinical impairment. Each WLL was performed at equivalent time intervals. The values of PaO2, PaCO2, Ers, and Rrs, determined right before starting each lavage, were considered the response of the lungs to the V. Antonaglia M. Ferluga N. Bianco P. P. Accolla Department of Intensive Care and Emergency, Respiratory Biomechanics Laboratory, Trieste University, Trieste, Italy