Bronchography with Hytrast

Contrast media which outline tube systems are well established radiodiagnostic adjuncts. Techniques and media may be changed both to increase the margin of safety for the patient and to improve radiographic contrast. In the radiographic demonstration of bronchi, early techniques, such as the insufflation of barium powder through a bronchoscope (Jackson, 1918) and the instillation of oily suspensions of bismuth, were quickly discarded as dangerous. Iodized poppy-seed oil (Lipiodol) was the first practical bronchographic agent (Sicard and Forestier, 1922) and was the only medium in general use for many years. The main disadvantage of Lipiodol was its long retention in pulmonary parenchyma in a radio-opaque form, especially where alveolar spill had occurred, so that the interpretation of serial radiographs used to demonstrate the progress of a pulmonary lesion was complicated. A granulomatous reaction to the oil was also an occasional occurrence. Dormer (1940) used Lipiodol as a vehicle for the introduction of sulphanilamide powder into the bronchi as a topical therapeutic agent in the control of bronchial infection. The sulphonamide increased the viscosity of the iodized oil, and it was soon recognized that by its addition alveolar spill was diminished, contrast was greater because the oil was less widely dispersed, and more complete post-bronchographic evacuation of the contrast medium was achieved by coughing, so that subsequent chest radiographs commemorated less frequently and grossly previous bronchographic attempts. The combination of 8 g. of sulphanilamide powder with 20 ml. of Lipiodol was used for bronchography in the Thoracic Surgical Unit in Edinburgh between 1950 and 1955. Some 800 bronchograms were made. Two patients experienced such severe dyspnoea as a consequence of bronchial obstruction by the viscous material that they very nearly suffocated, and in a third patient the subsequent development of acute nephritis was related to bronchography. Other complications were not encountered, and 75% of the bronchograms produced were then regarded as satisfactory. In a more critical retrospective evaluation of these bronchograms five years later (le Roux, 1962), it was thought that there was justification for dissatisfaction in 45% rather than 25% of the bronchograms. Improvement in bronchographic technique had made unacceptable that which in the past had been regarded as adequate. With more general use of the combination of sulphonamide with Lipiodol, marketed as Visciodol (Burrascano, 1955 ; Johnson and Irwin, 1959), the hazards of sensitivity to sulphonamide, of the formation of methaemoglobin, and of widespread bronchial obstruction by a too viscid preparation became apparent. In the attempt to obviate these disadvantages, water-soluble media were prepared. The first of these was diodone, combined with a thickening agent such as carboxymethylcellulose or polyvinyl pyrrolidone. This contrast medium proved clinically unacceptable because it was excessively irritating to the bronchi. In 1953 a new compound, propyliodone, was described. It was originally introduced as an aqueous suspension (Dionosil Aqueous) for which the advantages of rapid disappearance from the lungs and relative freedom from the risks of iodism were claimed. Its use was, however, often followed by a febrile reaction in the patient and, although isotonic with body fluids, it also proved irritating to the bronchial mucosa. The hazards of local anaesthetic sideeffects were enhanced because of the need to suppress more effectively the cough reflex with larger doses of topical anaesthetic. Propyliodone in arachis oil (Dionosil Oily) was then introduced as an alternative to the aqueous suspension, and this was shown to be less irritating and, on serial radiographs, was rarely retained in the bronchi or alveoli for longer than 48 hours. In Edinburgh after 1956 the oily suspension of propyliodone was adopted almost routinely as a bronchographic medium. While radiographic contrast was often less effective than with sulphanilamide powder in iodized poppy-seed oil, reactions were not observed, and the standard of bronchography was