Various authors have previously shown the benefit of ASV in the weaning phase,,: This is the first study, to our knowledge, that investigates the efficacy of ASV as the unique ventilation mode in patients in the medical ICU. Because ASV was shown to reduce total length of MV, the authors claimed that this additional benefit as an effect of the application of ASV from the beginning of MV. However, the protocol in the control group provided P-ACV for the whole length of MV, and pressure support ventilation (PSV) was contemplated only after the failure of the third spontaneous breathing trial (SBT), despite a general consensus and a strong support of the literature for the use of PSV as a weaning mode after an initial failed SBT. Robust evidence indicates the beneficial effects of PSV in patients able to trigger the ventilator compared with assisted/controlled modes,, and these may be of even greater relevance in patients at risk for scarce patient-ventilator interaction. Interestingly, more than one-half of enrolled patients had COPD and, thus, were prone to the development of asynchronies. Unfortunately, no data on this issue were presented, although a poorer patient-ventilator interaction in the P-ACV group could have seriously affected the results. We believe that the choice of not switching to PSV as soon as patients triggered the ventilator hampers the understanding of to what extent the benefit described in patients receiving ASV is due to the use of an assisted/controlled mode in the control group, notably because patients on ASV received totally assisted ventilation as soon as possible.