Figure 2

Mean functional residual capacities (±s.e.m.). Semi-Fowler's, left lateral, prone, right lateral, and supine positions for PEEP1 and PEEP10 with no pleural effusion (left panel) and with unilateral pleural effusion (right panel). No differences were observed between the four horizontal positions (left, prone, right, supine) with or without pleural effusion at PEEP1 and PEEP10. Semi-Fowler's position significantly increased FRC compared to all horizontal positions with and without pleural effusion at both PEEP levels as identified by asterisks.