2004N-0254 - Possible Barriers to the Availability of Medical Devices Intended to Treat or Diagnose Diseases and Conditions that Affect Children; Request for Comments
FDA Comment Number : EC11
Submitter : Mrs. Sandra Watkins Date & Time: 08/25/2004 04:08:47
Organization : American Society for Pediatric Nephrology
Other Organization
Category :
Issue Areas/Comments
GENERAL
GENERAL
Pediatric nephrologists rely on a number of technologies and devices to provide care for our patients. These include hemodialysis, continuous renal replacement therapy (CRRT), peritoneal dialysis and automated blood pressure measurement. Each of these technologies requires that appropriate medical devices be available that not only fulfill the desired function, but are also appropriately designed for infants and children of various sizes.
For hemodialysis, a specialized central venous dialysis catheter is necessary to deliver adequate blood flow to the dialyzer. Sizes must be available that can be inserted in infants as small as 1.0 kg, up to small adolescents of 50-60 kg. Since the development of the long term indwelling central venous catheter by Robert Hickman and his colleagues, significant strides have been made in the types and sizes of these catheters, but the selection is still limited. Several manufacturers have made commitments to the pediatric nephrology community to develop new catheters and continue to provide them to our patients. However, the number of vendors is quite limited, especially for smaller children and infants. To date the smallest long-term cuffed catheter is 8 Fr, yet this may be too large for some infants with renal failure, in whom long-term hemodialysis is life-sustaining therapy, or for some critically ill newborns with inborn errors of metabolism in whom hemodialysis or CRRT may be life-saving.

Compared to the potential adult market, there is small financial reward for companies to develop such catheters and to continue to provide them. New catheters for children require the same rigorous and expensive testing as for adult catheters; yet only a fraction will be sold compared to new catheters designed for adults. Often most of the technological problems have already been worked out during adult studies. Similar problems exist for choice of the tubing carrying the blood to and from the dialyzer used on dialysis machines. Ideally less than 8-10% of a patient?s blood volume should enter the dialysis circuit. For many of the currently available models of dialysis machines, the smallest volume tubing available is 40 ml, which may represent up to 15-20% of the blood volume of the average neonate. Smaller volume tubing is available by one vendor but is incompatible with a number of dialysis machine models. While no hemodialysis machine has been designed specifically for children, many models of machines have been adapted for use in infants and children. However, the lowest blood flow setting on some machines is only 50 ml/min, which is relatively high for use in small infants, making the dialysis procedure technically more difficult, and possibly less safe, than in larger children or adults.
While there have been significant strides over the years in the design and availability of medical devices for pediatric nephrology patients, challenges and barriers remain. The major barrier is the limited profitability of these devices compared to the adult market. Perhaps legislation similar to the Food and Drug Modernization Act of 1997 (FDAMA) mandating the development for and testing in children of new devices designed for use in adults would be helpful. The FDAMA and its successor legislation have been successful in increasing the information available on medication use in children.
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