Trudell Medical v. Monaghan Medical: Federal Circuit Partially Reverses OPEP Device Ruling
Trudell Medical International and D R Burton Healthcare pursued infringement claims against Monaghan Medical Corp. over two patents covering oscillating positive respiratory pressure (OPEP) devices. After 658 days of appellate proceedings, the Federal Circuit affirmed in part, reversed in part, and remanded — splitting the outcome and leaving key issues unresolved at the district court level.
Federal Circuit splits OPEP device patent verdict on remand
Trudell Medical International, together with licensee D R Burton Healthcare LLC, asserted two patents — US8539951B1 and US9808588B1 — against Monaghan Medical Corp., a competing manufacturer in the oscillating positive expiratory pressure (OPEP) therapy device market. The case reached the U.S. Court of Appeals for the Federal Circuit under case number 23-1777, filed on 21 April 2023, with the appeal originating in the District of Columbia circuit.
The Federal Circuit issued its disposition on 7 February 2025, ordering the case affirmed-in-part, reversed-in-part, and remanded. Separately, a portion of the appeal was dismissed. This mixed ruling means Monaghan Medical achieved a partial win at the appellate level on at least some claims or issues, while Trudell Medical and D R Burton preserved other aspects of their infringement case — which now returns to the lower tribunal for further proceedings consistent with the Federal Circuit’s guidance.
A resolution spanning 658 days is consistent with a substantively contested Federal Circuit appeal involving multiple patents and likely overlapping claim construction disputes. The partial reversal and remand suggest the lower court’s analysis was found wanting on at least one discrete issue — whether claim scope, validity, or damages — while surviving on others. The public record does not disclose which specific claims were reversed or the precise basis for partial dismissal, leaving the full commercial impact uncertain pending remand proceedings.
Filing to Appeal Dismissed in Part in 658 days
658 days — longer than the median Federal Circuit appeal, suggesting complex claim construction or extensive briefing
Federal Circuit partially reverses: what the mixed ruling means for both parties
Affirmed-in-part, reversed-in-part, remanded explained
A Federal Circuit order affirming-in-part and reversing-in-part means the appellate court found no reversible error on some issues from the lower proceeding, but identified legal error on at least one discrete issue warranting reversal. The remand instruction directs the lower court to reconsider those reversed issues in light of the Federal Circuit’s opinion. This is not a final resolution — further proceedings below are required.
Mixed appellate outcomeTrudell Medical preserves some claims but faces renewed proceedings
The affirmance component protects Trudell Medical and D R Burton’s position on at least a portion of their infringement case — those affirmed findings stand and cannot be relitigated on that basis. However, the reversal-in-part indicates the Federal Circuit rejected the lower court’s reasoning on at least one material issue, potentially narrowing claim scope or overturning a specific finding in Monaghan’s favour. The remand creates ongoing litigation risk and cost for the patent holders.
Partial preservationMonaghan Medical wins on remand but dispute continues
The reversal-in-part represents a meaningful appellate win for Monaghan Medical — at least one district court finding adverse to the defendant was overturned. However, the simultaneous affirmance means Monaghan did not prevail on all grounds it raised, and the remand resets proceedings on the reversed issues. Monaghan faces continued litigation exposure until remand proceedings conclude, and the partial dismissal of the appeal may have foreclosed some arguments entirely.
Partial appellate winOPEP device sector faces continued IP uncertainty post-remand
For manufacturers and distributors operating in the oscillating positive expiratory pressure device space, this Federal Circuit outcome does not deliver finality. The two asserted patents — US8539951 and US9808588 — remain in active dispute. Competitors should not assume freedom-to-operate based on the partial reversal alone; the affirmed portions of the lower ruling remain valid enforcement precedent, and remand proceedings may ultimately expand or contract the enforceable claim scope.
Sector IP risk remainsFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Trudell Medical International | Individual | Respiratory therapy device company — holder of US8539951 and US9808588 (OPEP technology)Search in Eureka ↗ |
| Co-Plaintiff | D R Burton Healthcare, LLC | Company | Search in Eureka ↗ |
| Defendant | Monaghan Medical, Corp. | Company | Monaghan Medical Corp. — respiratory device manufacturer accused of OPEP patent infringementSearch in Eureka ↗ |
| Plaintiff counsel | Judy He | Attorney | Counsel for Trudell Medical InternationalSearch in Eureka ↗ |
| Plaintiff law firm | Crowell & Moring, LLP | Law Firm | Representing Trudell Medical InternationalSearch in Eureka ↗ |
| Defendant counsel | Madison B. Waller | Attorney | Counsel for Monaghan Medical, Corp.Search in Eureka ↗ |
| Defendant law firm | Womble Bond Dickinson (US) LLP | Law Firm | Representing Monaghan Medical, Corp.Search in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | Court of Appeals for the Federal CircuitSearch in Eureka ↗ |
Official order — verbatim text
The Federal Circuit’s order — ‘AFFIRMED-IN-PART, REVERSED-IN-PART, AND REMANDED’ — is a compound disposition that simultaneously validates some lower court conclusions while rejecting others. The appellate standard of review for claim construction is de novo, meaning the Federal Circuit applies no deference to the lower tribunal’s legal interpretations. The partial dismissal indicates certain issues were procedurally barred from appellate review, likely due to waiver or lack of jurisdiction. Until remand proceedings conclude, neither party can claim a definitive outcome on all asserted claims.
US8539951 & US9808588 — Oscillating Positive Respiratory Pressure Device Patents
US8539951B1 (application no. US12/472215) and US9808588B1 (application no. US15/453767) both protect technology in the oscillating positive expiratory pressure device category — a class of respiratory therapy devices that generate oscillating pressure fluctuations in exhaled airflow to assist mucus clearance in patients with chronic respiratory conditions such as COPD, cystic fibrosis, and bronchiectasis. US9808588 is a later-filed application, suggesting it may cover improvements or refinements to the technology protected in the earlier US8539951.
Trudell Medical International is a recognized player in the respiratory therapy device space, and asserting two generationally linked patents against a direct competitor such as Monaghan Medical is consistent with a strategy to protect core OPEP device functionality across product iterations. For the respiratory device sector, OPEP patents carry significant commercial weight given the growing clinical adoption of airway clearance therapy and the relatively concentrated competitive landscape. The Federal Circuit’s split ruling suggests at least some of this IP is enforceable — elevating risk for any competing OPEP device manufacturer.
Should your OPEP device team run an FTO against US8539951 and US9808588?
Any company designing, manufacturing, or distributing oscillating positive expiratory pressure devices — or adjacent respiratory therapy products that generate oscillating airflow resistance — should treat both US8539951 and US9808588 as active enforcement risks. The Federal Circuit’s affirmance of at least part of the lower court ruling confirms that Trudell Medical has successfully defended portions of these claims at the highest patent appellate level. Waiting for remand resolution before conducting FTO analysis introduces unacceptable commercial risk.
PatSnap Eureka’s FTO Search Agent can map the independent and dependent claim structures of both patents against your product’s technical specifications, flag design-around opportunities in the OPEP pressure valve and oscillation mechanism space, and surface prior art that may inform invalidity arguments on remand. Eureka’s litigation monitoring tools also enable real-time tracking of remand proceedings so your IP team is never behind the curve on enforcement developments.
Run a freedom-to-operate analysis on US8539951B1 to assess your product’s exposure
Run FTO in Eureka →Similar Federal Circuit appeals in respiratory device patent litigation
Explore Federal Circuit cases involving respiratory therapy device patents, OPEP technology infringement claims, and mixed affirm-reverse-remand outcomes.
What this case signals for the respiratory device IP landscape
A split Federal Circuit ruling on OPEP device patents creates asymmetric risk for device makers and raises the stakes on claim construction strategy.
Mixed Federal Circuit outcomes reset infringement exposure — not end it
A reversal-in-part with remand is frequently misread as a defendant win. In practice, it means the dispute continues under revised legal parameters. Companies in the OPEP device space should not treat this ruling as clearance. The affirmed portions of the lower decision carry full precedential weight, and remand findings may restore or extend infringement liability.
Two-patent assertion creates layered exposure for device manufacturers
Trudell Medical’s assertion of both US8539951 and US9808588 across overlapping OPEP device technology suggests a portfolio enforcement strategy designed to capture multiple design approaches. Competitors should analyse both patents independently: a claim construction ruling adverse to Trudell on one patent does not automatically provide clearance on the other.
International v Monaghan — key questions answered
The Federal Circuit issued an order affirmed-in-part, reversed-in-part, and remanded on 7 February 2025. A portion of the appeal was also dismissed. The court found no reversible error on some issues from the lower proceeding but identified legal error warranting reversal on at least one discrete issue, sending those matters back to the lower court for further proceedings.
Trudell Medical International and D R Burton Healthcare LLC asserted two patents: US8539951B1 (application no. US12/472215) and US9808588B1 (application no. US15/453767). Both patents cover oscillating positive respiratory pressure device technology used in airway clearance therapy.
This compound Federal Circuit disposition means some lower court findings survive intact (affirmed), others were overturned due to legal error (reversed), and the case returns to the originating tribunal for further proceedings on the reversed issues. It is not a final resolution — both parties face continued litigation and neither has achieved a complete win or loss.
The public record does not support a freedom-to-operate conclusion for Monaghan Medical based on this ruling alone. The partial affirmance confirms that some infringement findings or claim constructions from the lower court remain valid. The remand may further alter the outcome. Any competitor in the OPEP device space should conduct independent FTO analysis before drawing conclusions from this mixed appellate decision.
The public record indicates the Federal Circuit dismissed part of the appeal, consistent with the Basis of Termination recorded as ‘Appeal Dismissed in Part.’ Partial dismissals at the Federal Circuit typically arise from procedural grounds such as lack of appellate jurisdiction over certain orders, waiver of arguments not raised below, or mootness of specific issues. The specific basis for partial dismissal in this case is not detailed in the available public record.
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