Fig. 3

Mean ICP and PRx induced changes. The interrupted interventions were presented in red. The value displayed is the mean value before interruption of the intervention, hence not entirely representative or comparable with not interrupted interventions. Panel (A). Mean ICP did not have a clinically important rise as compared with baseline, neither following the “Low VT/low PEEP” intervention nor during “Low VT/high PEEP” (one tailed paired t-test for noninferiority, both interventions p = 0.99). Similar results were achieved when including patients in whom the interventions were interrupted. In six of 27 (22%) patients, “Low VT/high PEEP” alone or both interventions were interrupted because the safety limit of ICP > 22 mmHg was reached. In one patient only the “low VT/low PEEP” intervention was interrupted. This patient had an increase in ICP over time, which might explain why the first attempted intervention “low VT/high PEEP” could be tolerated. Panel (B). None of the interventions produced significant changes from baseline in mean PRx, neither during intervention “Low VT/low PEEP” (paired t-test, p = 0.56) nor during intervention “Low VT/high PEEP” (p = 0.50). Similar results were achieved when including patients in whom the interventions were interrupted. VT, tidal volume; PEEP, positive end expiratory pressure; ICP, intracranial pressure; PRx, pressure reactivity index