FDA Patient Safety News: Show #2, March 2002

Camera Pill Cleared for Marketing

The FDA has recently cleared a tiny video camera that a patient can swallow, and that will take video pictures of the small intestine. It's called the Given Diagnostic Imaging System, and it's made by Given Imaging Ltd., of Norcross, Georgia.

Here's how it works. What the patient swallows is actually a capsule, a little more than an inch long, that contains the camera, a light, a transmitter, and batteries. As the device passes through the small bowel, it takes video pictures and transmits them via radio signals to a small recorder on the patient's belt. The images can then be interpreted by the physician. The capsule, which is not reusable, passes out of the body during normal defecation in about 8 to 72 hours.

The clinical use for this device is to visualize the small intestine when there's chronic or unexplained rectal bleeding and small bowel disease is a concern. It should only be used after the patient has received other imaging procedures to visualize the small bowel.

It's interesting to note that endoscopes can visualize only the upper part of the small intestine, whereas the camera can see its entire length.

There are circumstances where the camera can't be used. For example, when the patient has a cardiac pacemaker or other implanted electromagnetic device. And also when the patient has an intestinal blockage, or a significantly narrowed small bowel. In fact, before using the camera, an x-ray exam of the small bowel should be done if it's suspected that it may be too narrow.

And while the camera is in place, the patient should avoid bending, or stooping, or vigorous movement. Also, the video pictures taken by the camera can be lost if the patient comes too close to other devices that can cause electromagnetic interference, like mobile radios or MRI machines.

Additional Information:

New Device Clearances: Given® Diagnostic Imaging System K010312. August 1, 2001.

Skin Substitute for Diabetic Ulcers Approved

In another recent action, FDA approved a skin substitute that's used to help in the wound closure of diabetic foot ulcers. It's called Dermagraft, and it's made by Advanced Tissue Sciences of La Jolla, California. Basically, the product consists of human fibroblasts that are incorporated in a dissolvable mesh material.

When the product is placed on the ulcer, the mesh material is gradually absorbed and the human fibroblasts grow into place and replace the damaged skin. As they grow in, those fibroblasts produce many of the same proteins and growth factors found in healthy skin, and this helps in replacing and rebuilding damaged tissue in the ulcer.

The specific indications are for full-thickness diabetic foot ulcers that have been present for longer than 6 weeks. The ulcers can extend through the dermis, but they can't be so deep as to expose tendon, muscle, joint capsule or bone.

This product shouldn't be used if the ulcer is infected, or if it has sinus tracts, or tunneling into adjacent tissue. It also shouldn't be used on patients allergic to products derived from cows, because there's bovine serum in the packaging solution.

Additional Information:

New Device Approvals: DERMAGRAFT® - P000036. September 8, 2001.

Pacemaker for Treating Congestive Heart Failure

In the cardiovascular area, FDA recently approved a pacemaker that can treat some of the symptoms of moderate to severe congestive heart failure. In some heart failure patients, the left and right ventricles don't contract simultaneously, as they should. This device corrects that condition by providing specially timed electrical impulses to the ventricles.

It's called the InSync® Biventricular Cardiac Pacing System, and it's made by Medtronic, Inc., of Minneapolis. The system includes a pulse generator implanted in the patient's chest, which is connected to three lead wires that deliver the electrical impulses. One lead goes to the right atrium; the other two are placed in each of the ventricles, where they stimulate those chambers to beat simultaneously.

People with congestive heart failure typically experience fatigue and shortness of breath during exertion, often making it difficult to perform even the most routine tasks. During the clinical study of the Insync system, patients were implanted with the device and then randomized into two groups - one group of patients had the implant turned on. The control group didn't. When compare to the controls, the patients with the active implant were more likely to have an improvement in their heart failure classification, the distance they were able to walk, or their quality of life scores.

Even though this device may relieve some of the symptoms of congestive heart failure, it's not been shown to be useful in all heart failure patients. It should be used only in patients with moderate to severe symptoms of congestive heart failure whose ventricles are not contracting simultaneously and aren't likely to improve with additional drug therapy. And it shouldn't be used in patients whose congestive heart failure is reversible.

Additional Information:

New Product Clearances: Medtronic InSync® Biventricular Pacing System including the InSync® Model 8040 Pulse Generator, Attain™ LV Model 2187 and Attain™ CS Model 2188 Leads - P010015. August 28, 2001.

FDA Public Health Notification: Reducing Radiation Risk from Computed Tomography for Pediatric and Small Adult Patients

The FDA recently sent a public health advisory to radiologists, hospital risk managers and radiation health professionals, alerting them to the need to keep radiation doses during CT procedures as low as possible, particularly for children and small adults. Unless the settings on the CT unit are adjusted to accommodate to a small body, the child or small adult can receive more radiation than needed to get the diagnostic image.

And of course there's special concern about children getting unnecessary radiation exposure, because they're generally more sensitive to the harmful effects of radiation than adults.

To compound the problem, the overexposure of children and small adults during CT procedures can go unnoticed. With conventional x-rays, overexposing the patient generally means overexposing the film, and that results in an image that's too dark. So it's obvious to the operator that there's a problem. But with CT, the quality of the image may not be compromised, so the operator may have no idea that the patient is getting needless radiation.

The FDA advisory recommends several things.

* First, take several steps to optimize the settings on the CT scanner based on the patient's size.
* Second, when it's medically indicated, reduce the number of scans taken before the injection of contrast media.
* And third, when it's medically appropriate, consider using other imaging modalities that can sometimes provide the same diagnostic information with less or no radiation exposure-things like conventional x ray, or ultrasound, or MRI.

This FDA advisory recognizes the important benefits of CT scanning in diagnosing disease and trauma and guiding interventional procedures, and it doesn't suggest curtailing the use of this modality. What it does do is suggest ways to retain those benefits while minimizing the possible risk to a sensitive part of the patient population.

Additional Information:

FDA Public Health Notification: Reducing Radiation Risk from Computed Tomography for Pediatric and Small Adult Patients. November 2, 2001.

FDA Patient Safety News is available at www.fda.gov/psn