Linden v. ResMed Inc

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Craig L. Linden (California)
  • Defendant: ResMed Inc. (Delaware), ResMed Corp. (Minnesota), ResMed Holdings Pty Limited (Australia)
  • Plaintiff's Counsel: Hatch Law, PC; Brown Neri Smith & Khan, LLP
• Case Identification: 3:24-cv-01291, S.D. Cal., 07/21/2025
• Venue Allegations: Venue is alleged to be proper in the Southern District of California because Defendant ResMed Inc. is headquartered in the district, and all defendants are alleged to reside in the district and to have committed acts of infringement in the United States.
• Core Dispute: Plaintiff alleges that Defendant's connected sleep apnea treatment devices and associated software platforms infringe a patent related to methods for remote medical treatment involving real-time, interactive audio-visual communication and physical intervention.
• Technical Context: The lawsuit concerns the field of telehealth and remote patient monitoring, specifically systems that allow healthcare providers to diagnose conditions, monitor patient data, and remotely adjust therapeutic devices.
• Key Procedural History: The complaint asserts infringement "prior to the expiration of the U.S. Patent No. 9,639,150." This indicates the lawsuit seeks damages only for past infringement, as the patent is no longer in force. The complaint also alleges that Defendants have been aware of the patent since at least January 19, 2021, which serves as a basis for the willfulness allegation.

Case Timeline

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 9,639,150 - "Powered Physical Displays on Mobile Devices"

The Invention Explained

• Problem Addressed: The patent describes prior art remote interaction technologies as suffering from significant limitations, including being restricted to one-way communication, relying on pre-recorded information, and experiencing transmission delays ("latency") that made them unsuitable for real-time, physically interactive applications like medical treatment Compl. ¶¶18-22 '150 Patent, col. 6:47-col. 7:11
• The Patented Solution: The invention is a method for remote medical care that integrates real-time, two-way audio-visual communication between a patient and a remote provider with the ability to measure patient parameters and remotely administer a physical treatment or stimulus Compl. ¶23 '150 Patent, abstract A key aspect is the coordination of live communication with physical interaction, allowing a provider to diagnose a condition and then cause a physical change at the patient's location via a "physical output display" '150 Patent, col. 4:6-11 '150 Patent, Fig. 12
• Technical Importance: The claimed method purports to solve the problem of providing comprehensive, physically interactive remote medical care, which the patent asserts was a challenge unaddressed by prior art focused on generalized force-feedback or gaming Compl. ¶31

Key Claims at a Glance

• The complaint asserts independent Claim 1 and dependent Claims 2 and 9, pleading Claim 1 as exemplary for infringement allegations Compl. ¶41
• The essential elements of independent Claim 1 include:
  • Providing a first "internet and networking capable multi-media mobile electronic device" at a patient location, which has a "physical output display" and an "input transducer."
  • Providing a second, distinct device at a remote location.
  • Establishing an audio-video and data communication connection between the locations.
  • Conducting an audio-video conference where a treatment provider verbally elicits patient information.
  • Using the input transducer to measure a "patient parameter" that includes at least one "vital sign."
  • Transmitting a signal with the patient parameter to the remote device.
  • Forming a diagnosis based at least in part on the patient parameter.
  • Determining a treatment and generating a second signal associated with the treatment.
  • Sending the second signal to the patient's device to administer the treatment.
  • Using the second signal to "cause a physical interaction between the physical output display and the patient."
• The complaint reserves the right to assert additional claims Compl. ¶41

III. The Accused Instrumentality

Product Identification

• The accused instrumentalities are Defendants' "connected diagnostic and pulmonary treatment devices" and associated software, including the Airsense 10 and 11 series, AirCurve 10 and 11 series, AirView software, and myAir software (collectively, the "Accused Products") Compl. ¶¶1, 10

Functionality and Market Context

• The complaint describes the Accused Products as a system for treating conditions like sleep apnea Compl. ¶15 This system involves a patient-side device (e.g., a CPAP machine like the Airsense series) that delivers air pressure therapy. These devices are connected, transmitting data to cloud-based software platforms (AirView and myAir) Compl. ¶15
• This connectivity allegedly allows healthcare providers to remotely monitor patient data, diagnose issues, and manage treatment, which Plaintiff alleges practices the patented method Compl. ¶10 Compl. ¶15 The complaint highlights Defendants' marketing of these products as "award-winning medical devices and cutting-edge cloud-based software applications" for remote patient monitoring Compl. ¶15
• No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

The complaint references an exemplary claim chart as Exhibit B but does not attach it Compl. ¶46 The following summary is based on the narrative breakdown of Claim 1 provided in the complaint body.

• '150 Patent Infringement Allegations

• Identified Points of Contention:
  • Divided Infringement: The complaint acknowledges that the claimed method steps are performed by multiple parties (Defendants, patients, and treatment providers) Compl. ¶42 It alleges direct infringement based on a theory of "direction or control" under the standard set in Akamai v. Limelight (Compl. ¶42, Compl. ¶¶18-19). The central question will be whether Plaintiff can prove that Defendants condition the use of their system on the performance of the claimed steps by other actors and establish the manner and timing of that performance.
  • Scope Questions: The dispute may turn on whether the accused system falls within the scope of the claim terms. Key questions include:
    • Does the term "physical output display" read on a CPAP machine's mask and airflow delivery system?
    • Does a patient's breathing pattern, as measured by a CPAP machine, constitute a "vital sign" as that term is used in the patent?
    • Do the Accused Products, primarily data monitoring and therapy devices, qualify as "multi-media mobile electronic device[s]" capable of conducting an "audio-video conference" as required by the claim?

V. Key Claim Terms for Construction

• The Term: "physical output display"

• Context and Importance: This term is critical because infringement requires the accused device to have this component and for it to cause a "physical interaction" with the patient. The core of the dispute will be whether a system that delivers therapeutic air pressure meets this limitation, or if the term requires a more discrete, mechanical, or tactile output.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The specification describes the delivery of various "energy forms" including "pneumatic" energy '150 Patent, col. 4:1-5 '150 Patent, col. 10:60-65 This language may support an argument that a system delivering pressurized air is a form of pneumatic display.
  • Evidence for a Narrower Interpretation: Many embodiments in the patent describe tangible, mechanical outputs, such as a hugging teddy bear, an expanding pillow, or movable arms for simulated arm wrestling '150 Patent, Fig. 1 '150 Patent, Fig. 5 '150 Patent, Fig. 10 A defendant could argue these examples limit the term to devices that provide a discrete physical or tactile motion, rather than a continuous stream of therapeutic air.

• The Term: "vital sign"

• Context and Importance: The claimed method requires measuring a parameter that "includes at least one vital sign." The infringement case depends on whether the respiratory data collected by the Accused Products (e.g., apnea-hypopnea index, respiratory rate, leak data) qualifies.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The specification provides a non-limiting example: "a doctor may test the vital signs, strength and/or muscle/nerve reactions of a remote patient" '150 Patent, col. 12:61-63 Plaintiff may argue this broad language encompasses the sophisticated respiratory monitoring performed by the accused devices.
  • Evidence for a Narrower Interpretation: A defendant may argue that "vital signs" has a well-understood medical meaning (typically temperature, pulse rate, respiration rate, and blood pressure) and that the specialized data points collected by a CPAP machine do not fall under this definition. The patent does not explicitly define the term or list specific examples, leaving its scope open to interpretation.

VI. Other Allegations

• Indirect Infringement: The complaint alleges that Defendants "actively and willfully induce[] infringement" by patients and treatment providers who collectively perform all the steps of the asserted claims Compl. ¶44 The basis for this allegation is Defendants' alleged knowledge of the patent and their provision of the Accused Products with instructions on how to use them in an infringing manner Compl. ¶44 Contributory infringement is also alleged Compl. ¶45
• Willful Infringement: Willfulness is alleged based on Defendants having been "aware of the '150 Patent since at least January 19, 2021" Compl. ¶48 Plaintiff seeks treble damages as a result Compl., Prayer for Relief ¶B

VII. Analyst's Conclusion: Key Questions for the Case

1. A central issue will be one of divided infringement: Can the Plaintiff establish that ResMed "directs or controls" the actions of both patients and healthcare providers to the extent required to hold ResMed liable for direct infringement of the entire multi-actor method claim?
2. The case will also turn on definitional scope: Can the term "physical output display", which is exemplified in the patent with tactile and mechanical devices, be construed to cover the therapeutic airflow from a CPAP machine? Similarly, does the respiratory data collected by the accused system meet the "at least one "vital sign"" limitation?
3. Given that the patent has expired, a key evidentiary question will be one of damages: Assuming infringement is found, the dispute will focus on calculating a reasonable royalty for past use of the patented method during the enforceable term of the patent.