The effect of upper abdominal incision (Incision group) versus sham incision (Sham group) on ventilatory parameters (Protocol C). (A) Sample whole-body plethysmography recordings from the Sham and the Incision group at baseline (BL), on postoperative day (POD) 0, and POD 10. (B-F) Ventilatory parameters measured using the whole-body plethysmography system included minute ventilation (B), breathing frequency (C), tidal volume (D), inspiratory-to-expiratory time ratio (I:E ratio; E), and expiratory flow at 50% expired volume (EF50; F). A significant decrease in minute ventilation (B), breathing frequency (C), and I:E ratio (E) was observed for several days after the abdominal incision. (G) There was no difference in body weight between the Incision and the Sham groups. Data are presented as mean ± SD. n = 8 per group. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001 versus Baseline, and †P < 0.05; ††P < 0.01 †††P < 0.001; ††††P < 0.0001 versus Sham by two-way ANOVA with repeated measured in one factor, followed by Sidak’s multiple comparison tests.