Fig. 3

Evolution of diaphragm thickening fraction and its impact on thickness. a Individual values of perioperative ultrasound measurement of diaphragm thickening. Diaphragm function was assessed by calculation of right diaphragm thickening fraction (TF). A TF below 20% during SBT (black dashed line) defined low diaphragm thickening during. In this study, 66 patients had three measurements. The first assessment was made the day before surgery 36% (± 18), the second assessment was made at the time of spontaneous breathing trial (SBT) 17% (± 14) and the third, on day one postoperatively 12% (± 11). Repeated analysis of variance showed a significant difference between groups (P < 0.0001). b TF during SBT according to the three different thickness patterns. First column named loss of thickness was defined as a decrease of > 10% from baseline, second column named stable was defined by the absence of changes above 10% from baseline and third column named gain of thickness was defined by an increase of > 10% from baseline. The TF was in case of loss of thickness (14% (± 13)), versus stable patients (16% (± 14) and gain of thickness patients (23 (± 16)), ANOVA one-way analysis of variance P = 0.1. c Evolution of diaphragm thickening between preoperative day (D − 1) and SBT according to the three different thickness patterns. First column named loss of thickness was defined as a decrease of > 10% from baseline, second column named stable was defined by the absence of changes above 10% from baseline and third column named gain of thickness was defined by an increase of > 10% from baseline. The diaphragm thickening had a higher decrease in case of thickness loss (25% (± 17)), versus stable patients (15% (± 15) and gain of thickness patients (11 (± 21)), ANOVA one-way analysis of variance P = 0.02. *P < 0.05. TF: thickening fraction; SBT: spontaneous breathing trial