Objectives: To evaluate the position of the new Microcuff pediatric tracheal tube, based upon intubation depth markings.
Methods: With Institutional Ethics Committee approval and informed parental consent, we included patients from birth (> or = 3 kg) to 16 yr undergoing interventional cardiac catheterization requiring general anesthesia with orotracheal intubation. The intubation depth mark of the tracheal tube was placed between the vocal cords by direct laryngoscopy. The distance between tube tip and tracheal carina was measured from routinely taken cardiac catheterization posterior-anterior x-ray computer images with the patient supine and the head in a neutral position. Evaluation was performed for 20 tubes size 3.0 mm internal diameter (ID) and for ten tubes of each size from 3.5 to 7.0 mm ID.
Results: 100 patients were studied (47 girls; 53 boys). Tracheal tube tip advancement into the trachea ranged from 40.6% to 68.6% (median 51.4%). The shortest distance from tube tip to the tracheal carina was 15.7 mm using a 3.0 mm ID tube. Using a standard formula for tube insertion in children aged > or = two years [12 cm + (age/2)], in one patient the tube tip would have been below the carina and in seven patients the tube cuffs would have been placed within the larynx.
Conclusions: The intubation depth markings of the new Microcuff pediatric tracheal tube allow safe placement of the tracheal tube with a cuff-free laryngeal zone without the risk for endobronchial intubation. Placement using the intubation depth markings was superior to predicted insertion using a standard formula.