We demonstrated that application of deep inflations of 1 s duration and 30 cmH 2 O peak pressure in five minute intervals was sufficient to keep respiratory mechanics stable and thereby lung volume constant in low and high V T ventilation, without increasing PEEP over 2 cmH 2 O (Fig. 1) . We initially selected a relatively low PEEP level, because we plan to use the same PEEP in future studies on the molecular mechanisms of VILI, where high PEEP levels are known to be protective (many VILI models use no PEEP at all). Since RMs can be performed with varying duration, peak pressure and end-expiratory pressure [34] , we chose a very short type of RM, which we considered to be noninjurious to the lung and not to impair cardiac output. Accordingly, blood pressure and heart frequency were stable, regardless of the ventilation strategy. Although blood pressure was in a low range due to anaesthesia with pentobarbital, so that small changes might have been masked, this did not result in reflex tachycardia or impairment of microcirculation, as the pH values indicate (Table 3) . These stable cardiovascular conditions were also guaranteed by several supportive measures such as constant fluid support (200 mL/h), regular administration of pentobarbital via an intraperitoneal catheter, and an automated system to keep the body temperature constant. Further, it can be speculated that the low blood pressure is protective in this model, since edema formation is generally aggravated by high blood pressure.