The device assembled for breath sampling and etCO
measurement. The HME filter (A); the cell of the main stream capnometer CosmoPlus mod. 8100 (Novametrix Medical Systems Inc. Connecticut, USA) in order to measure etCO2 (B); a Mallinkrodt tracheal tube with an internal diameter of 9 mm in order to prevent any risk of collecting external air during sampling for eCO measurements (C). The tube 1 m long and with an internal diameter of 3 mm through which breath samples were suctioned (D).