Second, in our experience, hypoventilation during the procedure is only present during the short period of dilation of the trachea. To demonstrate this, we present end-tidal CO2 levels in five consecutive patients in our clinic. In these patients, we used the Ciaglia Blue Rhino technique. To assess ventilation during the procedure, we withdrew the endotracheal tube with the cuff just above the vocal cords; the cuff was then re-inflated. Tidal volumes were kept constant, and pressure limits were adjusted. For bronchoscopic guidance, we used a tracheal intubation fiberscope (Olympus LF-GP; Olympus Winter & Ibe; Hamburg, Germany). As can be seen in Figure 1
, during the 5 min when the scope was present in the airways (indicated by the arrow), there was no rise in end-tidal CO2 levels. Furthermore, even dilation does not result in a rise in end-tidal CO2 levels. Based on our experience, we prefer this technique above one in which a potential dangerous procedure must be performed (changing the endotracheal tube).