Fig. 1

Patient flow chart showing their classification according to leak pressure. The endotracheal tubes inserted were divided into two categories: used or replaced. The number of patients in each group is shown. [M₁] and [M₂] are derived from [I] and [J], respectively. [M] is the sum of [M₁] and [M₂]. [O₁] and [O₂] are derived from [I] and [J], respectively. [O] is the sum of [O₁] and [O₂]