Contrast media injectors are, by and large, reliable pieces of equipment. While not normally under the purview of clinical/biomedical engineering departments, this is changing as more departments participate in training and take on the maintenance for these devices.
Used by radiology departments and other owners of imaging systems, from x-ray to CT and MRI, contrast media injectors permit visibility-enhancing substances to be introduced at targeted locations within the human body. The presence of these substances makes it possible to produce imaging studies that readily distinguish one set of tissue from another. That can be crucially important to surgeons who need to know precisely where, for instance, lung tissue ends and tumor tissue begins. Various types of contrast agents exist to highlight specific parts of the body; most routinely, contrast is used to improve the views obtained of the vascular system.
Contrast media injectors are approximately the size of an ultrasound machine, and they come in either mobile or stationary configurations. The mobile version is customarily mounted to a wheeled pedestal. The other version is mounted to a rack or shelf in either the patient room or the control room.
At Allegheny General Hospital (part of the West Penn Allegheny Health System), Pittsburgh, clinical engineering specialist Craig Hunter, CBET, says the contrast media injector fleet consists of 25 machines deployed throughout radiology and the cardiac catheterization lab, with one in the operating room. “In general, most of our injectors give us few problems,” he says. “They tend to be fairly well designed and employ good materials, and aren’t subjected to a lot of physical abuse.”
Much the same story is told by Doug Miller, medical imaging specialist in the clinical engineering department at Community Health Network, Indianapolis, who is responsible for the care and feeding of 26 such machines spread among cath labs, MRI-CT suites, and interventional rooms at four hospitals. “The occasional broken drive belt is about the most serious mechanical problem we’ve had,” he says.
A Closer Look
The machine is made up of three components: an injector head (a syringe device into which the contrast media is loaded), a display panel (which shows user-defined settings for contrast volume, flow rate, and injection pressure), and an electronics box (containing operating system software, usually upgradeable). A common accessory is a contrast warmer, which is utilized to heat contrast media to body temperature before it is injected.
Durability and reliability are characteristic of most contrast media injectors. Rich Hamilton, a technical support specialist with MEDRAD, Warrendale, Pa, reports that the two parts a clinical/biomedical engineering department will rarely need to repair or replace are the device’s power supply and the interface board.
On the flip side, components most likely to cause problems are cables and connections. “Because the injector head is constantly being moved, cables and connections are subjected to tugging that can cause them to loosen, fray, or break,” says MEDRAD’s Frank DeSensi, director of global service marketing and sales. “Another common problem is found with syringe heaters—these dangle from the injector head, which likewise pull at the connections.”
One way to help prevent actual malfunctions is to provide general education to users of contrast media injectors. For example, a common cause of mechanical failure with these devices is contrast dripping onto their optical sensors. According to Hamilton, these sensors should be cleaned daily, but the task is simple enough that it can be delegated to the radiology technologists once they are taught how to do it. Moreover, as Hamilton points out, the best way to keep those sensors clean is to not allow contrast media to get on them in the first place. As such, Hamilton says there exists an opportunity for biomeds to instruct radiology techs on improving the techniques employed in handling the injector head (tip: always keep it pointing down).
According to Miller, his department has found clinicians “set the injection rate for milliliters per second without locking it in and then, because they’re in a hurry, inadvertently move the rate setting to milliliters per minute—so they’ll assume that because the contrast is coming out so slowly there has to be something wrong with the machine.” That is when his department gets the call to come out and take care of a problem that could have been avoided.
Rather than reflexively rush a biomed to the location of an apparently haywire contrast media injector, Miller’s department has made it a policy to first ask by phone a couple of pertinent questions of the user who has called in the trouble report. The questions help to indicate—or contraindicate—operator error. If the cause of the problem appears to be the operator’s, the biomedical department (while still on the phone) guides the user through the steps of restoring function and then offers a brief tutorial on how to avoid a repeat of the trouble in the future.
“Troubleshooting contrast media injector problems by phone has helped us reduce the number of trips to the equipment,” Miller says. “But this approach has limitations. It doesn’t work when the user is tied up with a case. In that instance, we have to go to the location and inspect it ourselves.”
John Reinhart, BMET supervisor of clinical engineering services at Ukiah Valley Medical Center and two other northern California hospitals, has far fewer contrast media injectors to worry about—a grand total of six. Even so, he says he is glad that service issues involving those come up only infrequently. “Our machines are very hardy; about the worst that happens is a leak will develop in a syringe and contrast will then find its way into the system internals,” he says. “So, mainly, we’re faced with the task of cleaning the media off of the operating mechanisms or the circuit boards. It’s a fairly simple process to open the casings in order to gain access to the mechanisms and boards. And the contrast media—if it’s newly leaked—cleans right up with alcohol pads or even a cotton swab dampened with plain water. Of course, we have to make sure the parts we’ve cleaned in this manner are thoroughly dried with the help of a can of air before we repower the system, especially where the circuit boards are concerned. And it helps that we make it a practice to address and resolve leakage promptly so as to catch the contrast media infiltration while it’s still only on the mechanical parts and before it has a chance to work its way deep inside where the circuitry is.”
Another common source of contrast media penetration is simple routine handling by clinicians. “A certain amount of contrast media ends up on the hands of the operators during the course of using the equipment for a clinical procedure,” Reinhart indicates. But by whatever means infiltration occurs, manufacturers recommend replacing circuit boards rather than attempting a cleanup when the contrast media is found to be crusted, caked on, and built up. “You can’t remove it with damp swabs and minimal scrubbing force when it’s caked like that,” he cautions. “My own rule of thumb is to buy a new part if cleaning the old one is going to take muscle. The reason is, of course, that you can do serious damage by using force to clean internal components.”
Invest in Training
Although serious troubles with contrast media injectors are few and far between, Reinhart is nonetheless ready for most of them since completing a comprehensive service training program offered by the manufacturer of his hospitals’ fleet. “Our administration is keen on having us go through as much factory training as possible. It makes significantly more economic sense, and it solves the problem of potentially long waits for help to arrive from the factory,” Reinhart says. “Being in a rural location as we are, it may be several days before the vendor’s field engineer, who’s based in the city 2 hours from here, can work it into his schedule to get out to us. So, with our in-house team factory trained, we can immediately take care of a majority of the problems ourselves.”
Reinhart also contends that being factory trained in contrast media injector servicing can help a biomed department further its ambition of being an indispensable asset that deserves a seat at the hospital’s decision-making table. “It’s just another way to demonstrate that we’re not only fix-it specialists, but are a resource for good ideas and education,” he says.
Still, while factory training greatly advances the clinical/biomedical departments’ proficiency at servicing, it does not endow them with total mastery of contrast media injector repair work, and gaps in their knowledge invariably limit the repairs they can perform. “We typically take first call to evaluate the problem, and then we’ll attempt to make whatever repairs we can in-house,” Hunter says. “If the problem is beyond our capabilities, then we turn to the manufacturer’s service team and hand it over to them.”
A hotly debated question for some biomed departments is whether or not to stock contrast media injector replacement parts. Miller’s hospitals decided the smart play was to keep parts on hand, but only the barest possible minimum. “Our thinking was that it doesn’t make financial sense to inventory all the parts that conceivably might need to be swapped out on these systems, since they don’t often break down,” he says. “Besides, you never really know what you’re going to need to replace when that occasional service call does come through. And whatever we don’t have here on hand we can order from the manufacturer. The part or parts will be delivered overnight, sometimes even that same day.”
The preventive maintenance (PM) of contrast media injectors is typically conducted on an annual basis, rather than every 6 months, with the exception being in high-use environments, those in which 30 or more patients per day are the norm.
Hunter says the PM program at his enterprise revolves, first, around performance assurance, to confirm that the equipment is operating per specifications; and, second, around electrical safety, to identify and resolve any conditions that might later pose a shock or electrical safety hazard. The PM work occurs in the biomed department’s shop. “We go out and round up the wheel-mounted contrast media injectors, then bring them back here and put them on the bench for inspection, cleaning, and, if needed, parts replacement,” he says. “We also have some units that are stationary because they’re permanently installed. These we have to test and maintain where they’re located.”
Clinical use of those stationary contrast media injectors begins at Allegheny General Hospital around 8 am daily, meaning PM inspections of those units must be scheduled prior to that hour. “It takes 3 to 4 hours to complete the PM process on one contrast media injector unit,” Hunter says. “I start my shift around 6:30 in the morning; that gives me up to 90 minutes to conduct my PMs. Since 90 minutes isn’t enough time to complete all the checks, I’ll split up the work over several days.”
For Miller, PMs entail “cleaning up the cases, checking the boards, inspecting the integrity of the cables, checking voltages on the batteries and the drive systems, replacing cracked cases, replacing burned-out lights, applying lubrication, and performing pressure tests.”
DeSensi says the best PM programs go beyond routine care, such as his company’s PM program that includes the monitoring of equipment operation as the basis for subsequently developing hardware and software upgrades to improve machine performance and to help prevent failures.
The useful service life of a contrast media injector is between 5 and 7 years. However, properly maintained, these devices can remain in operation for 20 years or more. “We recently retired a number of our injectors that were purchased back in the 1970s,” Miller says. “We had stopped using them on a regular basis a while back, but kept them in the fleet as backups in the event of an emergency. What we’ve discovered is that, overall, contrast media injectors are good, reliable workhorses.”
Rich Smith is a contributing writer for 24×7. For more information, contact .