by Dennis Crouch
The Federal Circuit recently affirmed a PTAB IPR decision invalidating claims of Masimo U.S. Patent RE47,218 (“the ’218 patent”) as obvious under 35 U.S.C. § 103. Masimo Corp. v. Sotera Wireless, Inc., 2022-1415 (Fed. Cir. Sept. 28, 2023) (nonprecedential). The Federal Circuit panel of Judges Prost, Wallach, and Chen determined (1) the Board correctly construed the disputed claim terms and (2) its obviousness ruling was supported by substantial evidence. Id. (authored by Judge Wallach).
The case is yet another example of a patentee’s broad claim language and attempts to avoid limitations coming back to bite during IPR proceedings. Unlike a decade ago, patent prosecutors are operating in today’s AIA world where IPR challenges have become commonplace. The old model of broad-as-possible clearly has deficiencies. To withstand post-issuance validity challenges, prosecutors should carefully craft claims early on with an eye toward narrower scope and avoiding abstraction even if you are doing enough to satisfy the USPTO on 112 and 101. Prosecutors can take full advantage of the 20 ‘free’ claims to pursue both broad and narrow protection. In the case here, the patent owner may have benefited from prosecuting more specific claims early on, as the disclosure arguably supported narrower alternatives that an IPR petitioner would have struggled to knock out.
The ’218 patent relates to an adaptive alarm system for use with pulse oximetry sensors in patient monitoring. A common problem is nuisance alarms generated when oxygen saturation briefly goes outside preset limits. This patent aims to improve alarm management by making the thresholds adaptive based on the patient’s current SpO2 levels and trends. Basically, an alarm threshold is calculated based upon a patient’s recent SpO2 levels rather than based upon an objective predetermined standard. Key adaptive alarm functions are:
- The alarm threshold changes over time based on the patient’s recent SpO2 level
- But, the threshold offset shrinks as SpO2 drops closer to a minimum – making it more sensitive to drops when the patient’s readings are already low.
Sotera petitioned for inter partes review (IPR) challenging the claims as obvious over a combination of prior art references including U.S. Patent Nos. 7,079,035 (“Bock”) and 6,597,933 (“Kiani”), along with PCT Publication WO 2009/093159 (“Woehrle”). The Board instituted review and ultimately ruled all instituted claims obvious based on these references.
On appeal, Masimo first argued the Board misconstrued the claim limitation “trigger a second alarm based on . . . exceeding the second alarm threshold” in finding obviousness over Bock/Kiani. The Board had treated the requirement as a “condition precedent”, but ruled that the claim does not require that exceeding the threshold directly triggers the alarm. On appeal, the court found this consistent with the plain claim language under Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (en banc), and the specification.
We agree with the Board that the plain meaning of “based on” and “threshold” in claim 1 are both broad, and this broad claim language does not exclude the use of additional alarm thresholds or other conditions to trigger an alarm. Further, claim 5 depends from claim 1 and provides for an additional condition in the form of a time delay, and Masimo does not dispute that the meaning of “based on” allows for additional conditions for triggering an alarm. We also agree with the Board that disclosure of an embodiment in the specification that does not include any additional thresholds or conditions for triggering an alarm does not support reading such a limitation into the claim.
This intrinsic evidence thus supports construing “based on” and “threshold” broadly — a ruling that was key to upholding the Board’s obviousness determination.
Masimo also challenged the Board’s interpretation of “predetermined” in certain claims as referring to a predetermined formulaic calculation rather than a fixed value. Again, the Federal Circuit upheld the Board’s construction as entirely consistent with the adaptive alarm thresholds described in the claims.
Ben Katzenellenbogen from Knobbe argued for the patentee appellant. Rudy Telscher from Husch took the other side. The IPR case here relates to the parallel litigation still pending in Masimo Corp. v. Sotera Wireless, Inc. and Hon Hai Precision Industry Co. Ltd., Civil Action No. 3:19-cv-01100-BAS-NLS (S.D. Cal.). In that case, the patentee Masimo asserted nine patents, all of which were challenged in IPR petitions. The PTAB granted 8 of those and cancelled all the challenged claims. Parallel appeals are still pending in several of the others. The infringement litigation has been stayed pending outcome of the IPRs.