Fig. 2

Changes of alveolar collapse, overdistension and global respiratory system compliance during a PEEP trial (beginning from 20 cmH₂O to 4 cmH₂O in steps of 2 cmH₂O every minute) in A) supine position without capnoperitoneum and B) Trendelenburg position with capnoperitoneum. Each point represents mean value of all 27 patients and whiskers show the standard deviation. Overdistension decreases towards lower PEEP values, while alveolar collapse increases simultaneously. The intersection between the lines representing alveolar collapse and overdistension indicates Best Compromise PEEP