Maintaining long-term central venous access by repetitive hepatic vein cannulation.

Long-term central venous access has become a critical issue in the treatment of pediatric patients. Exhaustion of access sites can lead to superior and inferior vena cava thrombosis, limiting the choices for central line placement. Under such circumstances, hepatic vein cannulation is a viable option. We present the cases of two patients who, combined, have undergone five hepatic vein catheterizations. One patient has received four consecutive central lines via a hepatic vein. This experience suggests that the hepatic vein is a reusable site of cannulation in patients with no other alternative for venous access.

The question of parallax-effect on radiographic assessment of short trachea in infants and children.

Disproportionately short trachea, can be recognized in AP chest radiographs of infants and older children taken during quiet respiration and showing an evaluable air tracheobronchogram, by the thoracic vertebral level of the carina (normally at T4 in neonates and infants, and at T5 in children two years of age or older). To establish the extent to which a parallax-effect of differing angles of X-ray beam relative to the patient can influence the radiologic assessment of carinal level, we measured the tracheal-vertebral distance at the carina in 29 lateral radiographs of neonates, infants and children, prepared diagrams of the loci of carinal beam intercept of the vertebral column for different angles of beam to body, from tracings of lateral radiographs of two 2-week-old infants, one with trachea of normal length and one with short trachea; of a nine-year-old child with short trachea, and of a ten-year-old with normal trachea, and made radiographs of a postmortem tracheobronchogram of a two-day-old infant at different beam angles. We conclude that tube-body angles of the order of 10-15 degrees from vertical at 27 inches (68.6 cm) or at 40 inches (101.6 cm) FFD do not significantly affect the apparent thoracic vertebral level of the carina in AP chest radiographs, and that a beam angle of 20 degrees or more from vertical is necessary to change the apparent level of tracheal bifurcation by one vertebral body, depending on the patient's age and on whether the patient's position relative to the X-ray beam is lordotic or anti-lordotic.(ABSTRACT TRUNCATED AT 250 WORDS)

Serial section-reconstruction of anomalous tracheobronchial branching patterns from CT scan images: bridging bronchus associated with sling left pulmonary artery.

The use of the technique of wax-plate serial section-reconstruction, based on contiguous axial plane CT images of the upper thorax, to prepare a replica of the central air-way (trachea and major bronchi) of an infant with sling left pulmonary artery type 2B, with bridging bronchus, abortive right main bronchus, and tracheal stenosis due to absence of the tracheal pars membranacea with "ring" tracheal cartilages is described. The technique is applicable to demonstration of the anatomic features of other abnormalities of branching pattern or caliber of the trachea and major bronchi.

Mediastinal masses: a system for diagnosis based on computed tomography.

A revised system for mediastinal mass differentiation has been developed and used at the Veterans Administration Medical Center, San Diego, and University Hospital of the University of California, San Diego. Contrast medium infusion or bolus computed tomography of the entire mediastinum is obtained, except when the mass is probably a thyroid mass (123I scan then obtained first) or an esophageal mass (barium swallow evaluation then obtained first). Next computed tomography density is determined, and only subsequently are masses of similar density subdivided by location. Further differentiation is based on computed tomography imaging parameters. A new algorithm for evaluation of mediastinal masses has resulted from use of this system. The system has been shown to increase specificity of differential diagnosis and to result in increased efficiency of evaluation of patients with mediastinal masses.