Fig. 5. Scanning electron micrograph of the internal surface of standard endotracheal tube and coated endotracheal tube after 24 h of mechanical ventilation. (a ) Note thick (41–52 μm) multilayering on lateral view. (b ) Study group: no biofilm visible. Note nonhomogeneous coating of silver-sulfadiazine and chlorhexidine (28–34 μm).