A Simple Peripheral Vascular Injector Which Uses Disposable Flastic Syringes

Abstract

The advantages of an injector for peripheral and selective arteriography are well known. These include constancy and reproducibility of injection rate and pressure; triggering of the x-ray machine or serialograph at the same point in the injection time after time; and, perhaps most important to the physician, removal of the operator from the roentgen beam. There is no shortage of commercial vascular injectors. They are readily available to anyone who can meet the purchase price, ranging from that of a good used car to that of a small airplane. To overcome these financial disadvantages, we have recently constructed an injector which combines the virtues of simplicity, reliability, low cost, and ease of construction. Driving Force: Our injector is driven by compressed air (which is available in each of our radiographic rooms). This is applied to a standard one-inch industrial air cylinder.2 Air flow is controlled by electrically operated solenoid valves. Injection Syringe: The injection syringe is one of the most expensive components of commercial injectors. The higher pressure devices use stainless steel syringes which are costly and require autoclaving after each use. At least one injector employs standard glass syringe barrels and finely machined steel plungers to avoid the binding effect of glass on glass. An occasional injector has made use of standard glass syringes, but with the admonition that a towel be placed over them in case of breakage. Our injector employs disposable plastic syringes,3 one of which is used for each patient and then thrown away. They have been shown to be compatible with water-soluble contrast media (1). At first glance, it would appear that the catheter would be blown off the syringe, since locking type fittings are not available on the plastic syringes, but this has not been the case. Apparently the tip of the syringe expands during injection and forms a tighter connection. Construction is illustrated in Figures 1 and 2. Pressures: The pressures developed are shown in Figure 3. It is apparent that the device is usable for those procedures which normally employ hand injection. Summary We have described a vascular injector which is inexpensive to build, uses readily available commercial parts, and substitutes ordinary disposable plastic syringes for the expensive steel syringes usually found in machines of this type.