Fig. 2.

Proportion of patients and histograms for gum-chewing group (GCG) and historical control group (HCG). (a) Proportion of patients with decreased tongue pressure (TP) at 2 weeks postoperatively (*p = 0.020, Fisher’s exact test), (b) Value obtained by subtracting the TP on the day before esophagectomy from that at 2 weeks postoperatively (p = 0.001, Mann–Whitney U test), GCG Median value, 0.77; interquartile range, − 1.6–3.2, HCG Median value, − 3.1; interquartile range, − 6.1 to − 0.3, (c) Number of fever (≥ 38.0 °C) days during 2 weeks postoperatively (p = 0.025, Mann–Whitney U test), GCG Median value, 1; interquartile range, 0–2, HCG Median value, 2; interquartile range, 1–4.