Hypotonic Duodenography

Abstract

Hypotonic duodenography is a method for showing duodenal anatomy without interference from peristaltic activity. It involves duodenal intubation, drug-induced atony, and visualization with barium and air (Fig. 1). Porcher (1) laid the technical groundwork for the procedure, using morphine to relax the duodenum; Liotta (2) added the duodenal tube; Jacquemet, Liotta, and Mallet-Guy (3) and subse quently Rösch and Salamoun (4) refined and exploited the method. Our version follows. Technic Passing the Nasogastric Tube: Local anesthesia of the nose and throat is produced with lidocaine and epinephrine nasal spray2 and/or by having the patient snuff 2 per cent viscous Xylocaine,2 which also lubricates the tube. Aided by sips of water, the patient swallows the tube. When it has entered the stomach, a flexible guide is inserted for torque control and, with the use of palpation and fluoroscopy, the tube is gently directed into the duodenum. Occasionally, the throat will be anesthetized so completely as to interfere with normal swallowing; in that situation, the using of fluoroscopy and the guide generally salvages the procedure. The flexible wire guide (Fig. 2) consists of Volkswagen speedometer cable from which the outer winding has been removed (as suggested by Gianturco). The nasogastric tube is also homemade from the insulation stripped from a 47-inch piece of Belden strain-gauge cable No. 8434.3 It is soft and slippery, with a 3 mm inside diameter and a 4 mm outside diameter. A Miller-Abbott tube tip and a female Luer-Lok adapter are tied to the ends of the tubing with size 00 rod-winding nylon thread. Both the tube and the guide are now available commercially.4 Inducing paralysis: Duodenal atony occurs suddenly about five minutes after the intramuscular injection of 60 mg (two 30 mg ampules) of Pro-Banthine5 and lasts about twenty minutes. The double dose and intramuscular injection appear to prolong the effect, compared to intravenous injection of smaller doses, as advocated by Barowsky (5). A dry mouth and possibly pupil dilatation, blurred vision, or tachycardia are expected but unimportant drug effects. Visualization: Under fluoroscopic control, the duodenal loop is distended with barium and radiographed at 120 kV in supine and prone-oblique positions. Air is then injected, and double-contrast roentgenograms are obtained in the same projections. The distended loop can obscure a localized lesion; visualization of all margins of the fully atonic duodenum is essential. We agree with Raia (6) that rapid, continuous gas distention is more effective than 50-cc syringe-injected increments. For this purpose, we use a cartridge-loaded gas syringe developed in our own laboratory (7).