Difference in elastic recoil pressure between the 1st and 2nd recordings at a volume equal to 50% of the insufflated volume
| ΔPel,RS cmH2O | ΔPel,L cmH2O | ΔPel,CW cmH2O | |
| ZEEP | 4.8c | 3.6c | 1.1b |
| PEEP | 1.7c(b) | 0.7b | 1.0c |
ΔPel,RS, ΔPel,L, ΔPel,CW: respiratory system; lung, and chest wall difference in elastic recoil pressure, respectively. ZEEP: zero end-expiratory pressure; PEEP: positive end-expiratory pressure. p-values are presented as difference from zero (difference between ZEEP and PEEP). b: p<0.05; c: p<0.001.