Further Experience with Drip Infusion Pyelography

Abstract

Our own further experience and that of others (6, 10, 15, 18) have confirmed the simplicity, safety, and reliability of drip infusion pyelography. As previously reported (16), excellent, anatomically complete pyelograms have been consistently obtained. Retrograde pyelography was only rarely necessary and studies were satisfactory in many patients with elevated blood urea nitrogen levels. The technic has been successful in detecting renovascular hypertension and has proved invaluable in assessing ureteral calculi and other disease processes involving the ureters. Quality nephrotomograms (the subject of another paper, 17) and voiding cystourethrograms were readily obtained. More than 1,000 infusions have been performed without a single serious reaction. Minor nausea, vomiting, and urticarial reactions showed no increase in incidence in comparison with standard low-dose technics. Dosage and Mechanism of Action Since our initial report, varying dosage regimens have been studied and the mechanism of action of the infusion technic has been re-evaluated. Some revision of original concepts has become necessary. As originally described, 1 cc per pound of 50 per cent Hypaque2 was mixed with 1 cc per pound of 5 per cent dextrose in water and the resultant solution was infused rapidly through an 18-gauge needle. The average adult received 300 cc of 25 per cent Hypaque. Films were obtained at ten, twenty, and thirty minutes, with modifications as indicated for nephrotomography, voiding cystourethrography, and the study of renovascular hypertension. The excellence of drip infusion seemed to depend upon diuresis and complete filling of the urinary tract; it was assumed that this diuresis was induced by the large volume of fluid infused. Hydration was felt to be instrumental in producing adequate urine flow, and patients were not dehydrated prior to study. The large amount of Hypaque administered was considered necessary only to insure adequate radiographic contrast. Further experience, however, suggested that this theory was not entirely correct. While the importance of diuresis and filling of the urinary tract remained unquestioned, it seemed that the contrast agent itself, without added water and without oral hydration, might be responsible for the large urine flow obtained with drip infusion. Contrast agents are osmotically active, having a diuretic action similar to that of urea and mannitol. With the small doses in standard pyelography the diuretic effect is probably minimal. With drip infusion, however, the large amount of contrast material given might reasonably be expected to induce a significant osmotic diuresis. A simple experiment designed to clarify this question was carried out. One hundred and sixty male patients3 were divided into 8 experimental groups of 20 each. Varying amounts of 50 per cent Hypaque with and without added water were administered and pyelograms obtained.