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Court “Breathes” Life Back into Accused Ventilator System

June 13, 2003

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Last Month at the Federal Circuit - June/July 2003

Judges: Bryson (author), Newman, and Mayer

In Tehrani v. Hamilton Medical, Inc., No. 02-1177 (Fed. Cir. June 13, 2003), the Federal Circuit vacated a grant of SJ of infringement to Dr. Fleur Tehrani.

Dr. Tehrani owns U.S. Patent No. 4,986,268 (“the ‘268 patent”), which relates to an apparatus and method for automatically controlling a respirator used for mechanical ventilation of a patient. Dr. Tehrani charged Hamilton Medical, Inc. and Hamilton Medical AG (collectively “Hamilton”) of infringing claims 1 and 16 of the ‘268 patent through the manufacture and sale of its Galileo ventilators. The claims require a device that first processes five data values, including measured levels of carbon dioxide and oxygen levels of the patient and then using these data values to calculate volume and breath frequency.

The Federal Circuit reviewed several claim-construction issues. In particular, the Court concluded that the term “representing” is broad enough to include “symbolizing” or “to stand for,” but elaborated that the term “represents” cannot be interpreted so broadly as to include any case in which two ideas are related in some way. Rather, the first item must be directly related to and stand for, or be a reasonable proxy for, the latter item. Moreover, because the patent uses the terms “indicative of” and “representing” interchangeably, they have the same meaning in the claims.

Claim 1 also includes a “means for processing” limitation. The Federal Circuit noted that “consistent with its precedent,” the structure corresponding to the processing function is the disclosed microprocessor that is programmed to perform the disclosed algorithm. However, the district court failed to determine the precise algorithm that is part of the recited structure. Nor was the Federal Circuit able to make this determination based on the record. Accordingly, the Court remanded the case to the district court to consider this issue.

Concerning claim 16, in what it called a “close” issue, the Federal Circuit ruled that the claims do not require that all of the method steps recited be performed automatically, thereby excluding manually input data. Concerning infringement, the district court had relied on a manually input “positive end expiratory pressure” (“PEEP”) value selected by an operator of the Galileo ventilators as satisfying the claimed “processing data representing . . . oxygen levels.” The Federal Circuit found that although there is some association between the PEEP level and the level of oxygen in a patient in that the PEEP level may affect the oxygen level, there was no evidence to support the conclusion that the PEEP level “represents” the patient’s oxygen level, as claimed.

Having resolved these claimconstruction issues, the Federal Circuit ruled that numerous issues of fact remained concerning whether the accused Galileo product infringes claims 1 and 16. Therefore, the Federal Circuit vacated the district court’s SJ of infringement and remanded for further proceedings on the issue.