IP Law Daily, PATENT—Fed. Cir.: Invalidity of patent for mechanical ventilator upheld, (Jun 28, 2023)

By Donielle Tigay Stutland, J.D.

The Federal Circuit affirmed the invalidation of a patent for an automatic ventilator, agreeing with the PTAB that it was obvious to combine prior art.

The U.S. Court of Appeals for the Federal Circuit affirmed a determination by the Patent and Trial Appeal Board (“Board”) that claims of a patent related to mechanical ventilators were invalid as obvious. The court determined that the Board did not abuse its discretion in crediting an expert, and the court agreed with the Board that it would have been obvious to combine prior art references (Tehrani v. Hamilton Technologies LLC, June 28, 2023, Stark, L.).

Background. The dispute centers on a patent for technology related to ventilators. Dr. Tehrani owns and was the inventor of U.S. Patent No. 7,802,571 (the ’571 patent). The ’571 patent is entitled “Method and Apparatus for Controlling a Ventilator,” and relates to “a method and apparatus for controlling a ventilator based on the measured levels of oxygen of the patient on the ventilator, as well as other physical conditions of the patient.”

Hamilton Technologies LLC (Hamilton) is the licensee of a different patent owned by Dr. Tehrani. Hamilton petitioned for inter partes review (IPR) of the ’571 patent and Board instituted an IPR and ultimately concluded that claims 1-6, 9-12, 29-33, and 41 of the ’571 patent were invalid as obvious. The patent owner appealed.

Expert testimony. The patent owner raised an issue on appeal that the Board should not have credited Hamilton’s expert, Dr. Richard Imbruce, because he is “a) not a respiratory therapist, b) none of his listed patents [are] on mechanical ventilation, and c) he was disqualified in another case for offering expert testimony on a subject he was not familiar with.” The court analyzed the Board’s determinations as to what weight to give the expert testimony for abuse of discretion.

It was noted that the expert whose testimony was challenged has decades of experience with ventilator devices and portable oxygen generators, including developing clinical protocols for new modalities in artificial ventilation and oxygen delivery therapies for hemorrhagic shock in wounded soldiers. The Board found Dr. Imbruce’s testimony “adequate,” and the court noted that it “was free to do so.” The court stressed that, even assuming there was error in the Board’s failing to expressly find that Dr. Imbruce was a person of ordinary skill in the art, such error was harmless, because “Dr. Imbruce plainly has the qualifications to make him such a person.”

Additionally, the patent holder argued that the Board should have construed the claim term “for a next breath of the patient” as controlling PEEP and FIO2 for “a patient’s breath immediately following in time” or “the next breathing cycle of the patient.” The software algorithm for the device includes a proportional, integral, derivative (“PID”) control program which “is designed to automatically adjust” the fraction of inspired oxygen in a patient’s inspiratory gas (“FIO2”) and the patient’s Positive End-Expiratory Pressure (“PEEP”) “based on at least the measured oxygen levels of the patient.” The expert proposed plain and ordinary meaning as not limited to the immediate next breath or breathing cycle. However, the court indicated that the Board did not even construe the claim term. The Board had determined that the claim limitation was taught in the prior art combinations “regardless of whether we adopt Patent Owner’s or Petitioner’s claim construction.”

Factual findings. The court next reviewed at the Board’s ultimate obviousness determination de novo and underlying fact-findings for substantial evidence.

Looking at the argument of prior art references, Dr. Tehrani argued that two of the offered examples of medical studies (by Anderson and Carmichael) which constitute the prior art can be distinguished. The patent holder argued that Anderson’s use of look up tables contradicts the ’571 patent’s PID control and, further, that Carmichael does not teach the use of an automatic ventilator and a ratio of PEEP/FIO2.

However, the Federal Circuit concluded that the evidence supported the Board’s finding that “it would have been obvious to employ Anderson’s automated system to implement Carmichael's treatment protocol for adjustment of PEEP and FIO2 in ARDS [(Acute Respiratory Distress Syndrome)] patients.” The court found that many of the patent owner’s arguments were focused on pointing out limitations that are not present in individual prior art references, but what matters is what the combination of references collectively contain, not what they individually contain or lack. The combination of prior art disclosed all the limitations in the challenged claims. The court affirmed the Board’s final decision finding the claims invalid for obviousness.

The case is No. 22-1732.

Attorneys: Mark Robert Kendrick (Kendrick Intellectual Property Law) for Fleur Tehrani. Patrick C. Keane (Buchanan Ingersoll & Rooney P.C.) for Hamilton Technologies LLC.

Companies: Hamilton Technologies LLC

Cases: Patent FedCirNews USPTO