After intubation , patients were randomly assigned to 1 of 2 groups : ( 1 ) deliberate bronchial intubation with subsequent withdrawal of the TT to 2 cm above the carina ( main-stem group ) or ( 2 ) transmitted visual signal from a bright light at the TT tip on the skin at the suprasternal notch after inserting the Trachlight into the TT ( transillumination group ) .