DCT
1:22-cv-01050
Critical Device Corp v. Enteral Access Tech Ltd
Key Events
Amended Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Critical Device Corporation (Ohio)
- Defendant: Enteral Access Technologies Ltd (U.K.)
- Plaintiff’s Counsel: Weston Hurd LLP
- Case Identification: Critical Device Corporation v. Enteral Access Technologies Ltd, 1:22-cv-01050, N.D. Ohio, 05/31/2023
- Venue Allegations: Plaintiff alleges venue is proper because Defendant, a foreign corporation, does business in the United States—including seeking FDA approvals, registering trademarks, and displaying products at trade shows—but lacks sufficient contacts with any single state to be subject to jurisdiction there.
- Core Dispute: Plaintiff alleges that Defendant’s DoubleCHEK medical device infringes two patents related to apparatuses and methods for measuring characteristics of bodily fluids to ensure the proper placement of enteral feeding tubes.
- Technical Context: The technology concerns handheld, disposable devices designed for clinicians to safely and accurately test the pH of gastric aspirate at a patient's bedside to confirm nasogastric feeding tubes are correctly placed in the stomach and not the lungs.
- Key Procedural History: The complaint notes that on April 12, 2022, Plaintiff’s counsel sent a cease and desist letter to Defendant, providing a copy of one of the patents-in-suit and alleging infringement. This event forms the basis for the allegation of willful infringement.
Case Timeline
| Date | Event |
|---|---|
| 2005-02-08 | U.S. Patent No. 9,173,602 Priority Date |
| 2013-12-12 | U.S. Patent No. 9,658,125 Priority Date |
| 2015-11-03 | U.S. Patent No. 9,173,602 Issues |
| 2017-05-23 | U.S. Patent No. 9,658,125 Issues |
| 2022-03-XX | Defendant demonstrates DoubleCHEK device at U.S. trade show |
| 2022-04-12 | Plaintiff sends cease and desist letter to Defendant |
| 2023-05-31 | Amended Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 9,173,602 - "Fluid Characteristic Measurement"
The Invention Explained
- Problem Addressed: The patent’s background section describes the clinical challenge of accurately verifying the placement of nasogastric tubes. It notes that conventional methods for testing gastric pH can be "messy and inaccurate," time-consuming, and create risks of personnel exposure to "gastric aspirate and other bodily fluids" (’602 Patent, col. 1:44-48, col. 2:23-26).
- The Patented Solution: The invention provides a self-contained apparatus for fluid analysis, comprising an inner housing for the sample and a detection indicator, which "nests or telescopes" into a protective outer "exoskeleton" (’602 Patent, col. 2:35-37). This nested design is intended to protect the inner housing from stress that could cause leakage and provide an additional barrier against fluid exposure (’602 Patent, col. 2:37-41).
- Technical Importance: The invention provided a closed-system, disposable device for bedside pH testing, aiming to improve safety for clinicians and accuracy in confirming feeding tube placement (’602 Patent, col. 1:49-53).
Key Claims at a Glance
- The complaint asserts independent claims 1, 13, and 16 (apparatus claims) and 22 and 26 (method claims) (Compl. ¶19).
- Independent Claim 1 recites an apparatus with three core elements:
- a detection indicator configured to display a visual indication of a fluid characteristic;
- a housing with an interior chamber containing the indicator; and
- an exoskeletal member into which the housing is "nestably disposed."
- Independent Claim 13 recites an apparatus with a housing, a detection indicator, and adds limitations for a "manually-operated valve disposed between the conduit and the interior chamber."
- Independent Claim 16 recites an apparatus comprising a "first body portion" and a "second body portion" that mate to form a liquid conduit and an interior chamber.
- Independent Claims 22 and 26 recite methods of using a fluid characteristic indicator, comprising steps of coupling the indicator to a patient conduit, "aspirating a quantity of body fluid," and "insufflating air...to flush body fluid therefrom."
- The complaint reserves the right to assert dependent claims (Compl. ¶19).
U.S. Patent No. 9,658,125 - "Fluid Characteristic Indicator"
The Invention Explained
- Problem Addressed: The patent background identifies the need for an "immediate and reliable indication" of fluid characteristics, such as confirming gastric tube placement via pH measurement (’125 Patent, col. 1:24-34). It notes that inaccurate readings can result from improper fluid exposure to the indicator.
- The Patented Solution: The invention is a fluid characteristic indicator containing a "diffuser" within a tubular housing (’125 Patent, Abstract). The diffuser is a structured component that supports the indicating element and has at least one fluid channel designed to "direct fluid toward the indicating element" (’125 Patent, col. 2:35-42). This controlled fluid flow is intended to make the "exposure and saturation of the indicator more accurate" and reduce the sample volume needed for a reading (’125 Patent, col. 1:55-62). The patent's figures depict diffusers with helical, spiral, or star-shaped channels (e.g., ’125 Patent, Figs. 3A-3H).
- Technical Importance: The invention's focus on a diffuser structure aimed to improve measurement reliability and efficiency by actively managing fluid dynamics within the testing device (’125 Patent, col. 2:57-67).
Key Claims at a Glance
- The complaint asserts at least independent claim 1 (Compl. ¶20).
- Independent Claim 1 recites a fluid characteristic indicator with essential elements including:
- a housing having a generally tubular body;
- a diffuser at least partially disposed in said body;
- the housing and the diffuser cooperatively defining a fluid chamber; and
- a fluid characteristic indicating element disposed around an outer portion of the diffuser.
III. The Accused Instrumentality
Product Identification
- The "DoubleCHEK" device (Compl. ¶18).
Functionality and Market Context
- The complaint alleges the DoubleCHEK device uses a "valve and pump system to collect small samples of aspirate" and direct them to CO2 and pH indicators (Compl. ¶18). This functionality is intended to prevent the misplacement of feeding tubes into a patient's lungs (Compl. ¶18). A diagram of the device shows separate windows for viewing pH and CO2 test results (Compl. ¶18, Figure 1(a)). The complaint alleges that Defendant is actively introducing the DoubleCHEK product into the United States, has demonstrated it at trade shows, and has positioned it as a "dramatic improvement" over Plaintiff's own RightSpot® product (Compl. ¶¶ 25, 29, 33). A photograph from a trade show depicts a poster for the DoubleCHEK device, describing it as "Combining CO₂ & pH indicator checks into one single, simple-to-use device" (Compl. p. 8).
IV. Analysis of Infringement Allegations
U.S. Patent No. 9,173,602 Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a detection indicator configured to display at least one visual indication when in contact with a liquid from a body of a subject, | The DoubleCHEK uses a pH detection indicator that displays a visual indication when in contact with a bodily liquid. | ¶34 | col. 2:28-33 |
| said at least one visual indication representing a value of a characteristic of the body liquid; | The DoubleCHEK uses a pH detection indicator. | ¶34 | col. 2:28-33 |
| a housing with an interior chamber containing said detection indicator and configured to receive the body liquid and to provide contact between the body liquid and the detection indicator; | The DoubleCHEK uses a tubular body housing with an interior chamber containing the detection indicator. | ¶34 | col. 2:33-36 |
| an exoskeletal member into which said housing is nestably disposed; | The DoubleCHEK has an indicator and housing, and an exoskeletal member that meets all these requirements. | ¶34 | col. 2:35-37 |
Identified Points of Contention
- Scope Questions: A central question may be whether the DoubleCHEK device possesses the claimed two-part structure of a "housing" that is "nestably disposed" within an "exoskeletal member." The complaint’s allegation is conclusory ("meets all these requirements") (Compl. ¶34), and the provided visual evidence depicts an apparatus that may be a single, integrated body (Compl. ¶18, Figure 1(a)). The litigation may focus on whether the accused product's physical construction maps onto these distinct claim elements as described in the ’602 Patent specification.
U.S. Patent No. 9,658,125 Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A fluid characteristic indicator comprising: | The DoubleCHEK is a fluid characteristic indicator. | ¶41 | col. 2:9-10 |
| a housing having a generally tubular body; | The DoubleCHEK uses a tubular body housing with an interior chamber containing the detection indicator. | ¶41 | col. 2:11-12 |
| a diffuser at least partially disposed in said body; | The interior chamber of the DoubleCHEK containing the detection indicator is a diffuser which spreads fluid particles evenly. | ¶41 | col. 2:35-39 |
| the housing and the diffuser cooperatively defining a fluid chamber | The interior chamber of the DoubleCHEK containing the detection indicator is coupled with the housing cooperatively defining a fluid chamber. | ¶41 | col. 2:14-16 |
| a fluid characteristic indicating element disposed around an outer portion of the diffuser at said first section; | The DoubleCHEK ("indicating element") is disposed around an outer portion of the diffuser first section. | ¶41 | col. 2:43-45 |
Identified Points of Contention
- Technical and Scope Questions: The primary point of contention appears to be the "diffuser" limitation. The complaint alleges that the "interior chamber of the DoubleCHEK...is a diffuser" (Compl. ¶41). This raises the question of whether a passive chamber can meet a claim limitation for a "diffuser," which the ’125 Patent specification describes as an active component with specific structures like channels, vanes, or spirals designed to direct fluid flow (’125 Patent, col. 2:35-51). The analysis will likely focus on whether the accused device contains any internal structure that performs the specific fluid-directing function of the claimed diffuser.
V. Key Claim Terms for Construction
The Term: "exoskeletal member into which said housing is nestably disposed" (’602 Patent, Claim 1)
- Context and Importance: This structural relationship is a cornerstone of Claim 1 of the ’602 Patent. The infringement determination will depend on whether the accused product is found to have two distinct components corresponding to the "housing" and "exoskeletal member" arranged in this nested configuration.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: Practitioners may argue that the term "exoskeletal member" should be construed broadly as any outer casing that provides protection, citing general language in the specification.
- Evidence for a Narrower Interpretation: The specification consistently describes and depicts two separate components, stating the "apparatus comprises a...housing, and an exoskeleton into which the housing nests or telescopes" (’602 Patent, col. 2:35-37). Figures such as FIG. 55 and FIG. 72 show a distinct housing (5502) and a separate exoskeleton (7226) that slides over it, suggesting the terms refer to physically separable parts.
The Term: "diffuser" (’125 Patent, Claim 1)
- Context and Importance: This is the central technical element of the ’125 Patent. The viability of Plaintiff's infringement allegation hinges on construing this term to read on the accused product. Practitioners may focus on this term because the complaint alleges that an "interior chamber" itself is the diffuser, which may not align with the term's technical meaning.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: A party might argue for a functional definition, contending that any structure that causes fluid to spread meets the limitation, though the specification does not appear to provide explicit support for this.
- Evidence for a Narrower Interpretation: The specification repeatedly describes the diffuser as a distinct component with structures that actively manage fluid flow, such as having "at least one fluid channel to direct fluid toward the indicating element" (’125 Patent, Abstract) or channels formed as a "spiral or helix" or by "a number of vanes" (’125 Patent, col. 2:40-45). This suggests "diffuser" refers to a specific, engineered component, not merely the chamber that contains it.
VI. Other Allegations
- Indirect Infringement: The complaint alleges inducement of infringement, stating that Defendant instructs end users on the infringing use of the DoubleCHEK device through "demonstrations...at trade shows and descriptions and videos on its web site" (Compl. ¶21, ¶45).
- Willful Infringement: The complaint alleges willful infringement of the ’602 Patent based on pre-suit knowledge. It asserts that Defendant had "actual knowledge" of the ’602 Patent as of April 12, 2022, the date Plaintiff sent a cease and desist letter that included a copy of the patent (Compl. ¶¶ 22, 23, 42, 43, 46).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of definitional scope: can the term "diffuser," described in the ’125 Patent as a structured internal component with fluid channels, be construed to read on the accused product’s alleged "interior chamber"? Similarly, for the ’602 Patent, does the accused product’s body comprise a distinct "housing" that is "nestably disposed" within an "exoskeletal member," or is it a unitary structure outside the claim’s scope?
- A key evidentiary question will be one of technical mapping: what evidence will be presented to demonstrate that the internal structures of the DoubleCHEK device perform the specific fluid-directing functions of the claimed "diffuser" or possess the two-part nested structure of the claimed "housing" and "exoskeletal member"? The complaint’s allegations are presently conclusory on these critical technical points.