IT WAS ERROR TO LIMIT CLAIMS TO PREFERRED EMBODIMENT, PARTICULARLY LIMITATIONS NOT “CENTRAL” TO THE INVENTION

Medegen MMS, Inc. v. ICU Medical, Inc., [2008-1114] (November 20, 2008) [DYK, Rader, Walker] The Federal Circuit reversed summary judgment of non-infringement of U.S. Patent No. 5,730,418 because the district court erred in its construction of the claim term “plug.”
DISCUSSION: The district court construed “plug” as “an elastomeric part that either pivots about a reduced diameter portion or buckles, to establish a fluid flow path.” The district court relied heavily on the finding that “the preferred embodiment[s] of the invention, as discussed throughout the specification and claims, all consistently discuss a plug” with the elastomeric feature, and that the specification “nowhere describes a non-elastomeric or rigid plug.” The district court also stated that Medegen “needed to indicate in the ’418 Patent that a skilled artisan could use alternative plugs and describe how such plugs would perform the functions of controlling fluid flow and achieving minimum fluid displacement in the context of its invention.” The Federal Circuit noted that the term “plug” is not expressly limited by the language of the claims—that is, the elastomeric limitation is not found within the claim itself. The Federal Circuit also noted that there was no contention that the ordinary meaning of the term “plug” does not include a rigid plug or that it has a special meaning in the medical field that requires elastomericity, or that there was any clear disclaimer of non-elastomeric plugs in the specification. The Federal Circuit found that the patent was clear that the elastomeric feature of the plug is merely an example of how to create a fluid flow connection between the inlet valve and the internal fluid chamber, and concluded that the use of an elastomeric plug to establish that fluid flow connection is not central to the invention itself, which is directed to reducing retrograde flow.
COMMENT: It is interesting that Judge Walker, a district court judge sitting by designation, dissented, expressing the frustration all district court judges must have with claim construction, and in particular with construing claims in light of the specification, without importing limitations.