Limitations
overdistention
The present study has some limitations. A major one is that it is a single-centre study with a small sample size. Notably, the interrupted group is too small, to draw any firm conclusions from. The power analysis was based on local retrospective ICP data in parallel with clinical judgement, in combination with a previous observational study [It is possible, albeit not proven, that another study design with slowly increasing PEEP would have given other changes in ICP. We did not test the response to high tidal volume and high PEEP, because of the risk of overdistention. However, the study design allowed us to explore the effect of low tidal volume and high PEEP separately, which had not been done before. A limitation is also the fact that we did neither have recordings of brain tissue oxygen tension, nor cardiac output measurement, since this type of devices are used sparingly in our ICU in this patient group.