Applying Medical Device Informatics to Enable Safe and Secure Interoperable Systems: Medical Device Interface Data Sheets.

This article describes the concept of Medical Device Interface Data Sheets (MDIDSs) to document and characterize medical device interface data requirements, the processes for creating MDIDSs, and its role in supporting patient safety and cybersecurity of current systems while enabling innovation in the area of next-generation medical Internet of Things (IoT) platforms for integrating sensors, actuators, and applications (apps).

Respiratory Gas Analysis-Technical Aspects.

A technology-focused review of respiratory gas analysis, with an emphasis on carbon dioxide analysis, is presented. The measurement technologies deployed commercially are highlighted, and the basic principles and technical concerns of infrared spectroscopy and mainstream versus sidestream gas sampling are discussed. The specifications of particular interest to the clinician, accuracy and response time, and the related standard, with typical values for a capnometer, are presented. Representative time and volumetric capnograms are shown with the clinically relevant parameters described. Aspects of the terminology in present-day use and the need for clarity in defining what is a breath and an end-tidal value are reviewed. The applications of capnography of particular interest to the anesthesiologist are noted, and key references are provided. Ongoing developments with respect to respiratory gas analysis, and those that will impact it, are noted.

The Need to Apply Medical Device Informatics in Developing Standards for Safe Interoperable Medical Systems.

Medical device and health information technology systems are increasingly interdependent with users demanding increased interoperability. Related safety standards must be developed taking into account these systems' perspective. In this article, we describe the current development of medical device standards and the need for these standards to address medical device informatics. Medical device information should be gathered from a broad range of clinical scenarios to lay the foundation for safe medical device interoperability. Five clinical examples show how medical device informatics principles, if applied in the development of medical device standards, could help facilitate the development of safe interoperable medical device systems. These examples illustrate the clinical implications of the failure to capture important signals and device attributes. We provide recommendations relating to the coordination between historically separate standards development groups, some of which focus on safety and effectiveness and others focus on health informatics. We identify the need for a shared understanding among stakeholders and describe organizational structures to promote cooperation such that device-to-device interactions and related safety information are considered during standards development.

Capturing Essential Information to Achieve Safe Interoperability.

In this article, we describe the role of "clinical scenario" information to assure the safety of interoperable systems, as well as the system's ability to deliver the requisite clinical functionality to improve clinical care. Described are methods and rationale for capturing the clinical needs, workflow, hazards, and device interactions in the clinical environment. Key user (clinician and clinical engineer) needs and system requirements can be derived from this information, therefore, improving the communication from clinicians to medical device and information technology system developers. This methodology is intended to assist the health care community, including researchers, standards developers, regulators, and manufacturers, by providing clinical definition to support requirements in the systems engineering process, particularly those focusing on development of Integrated Clinical Environments described in standard ASTM F2761. Our focus is on identifying and documenting relevant interactions and medical device capabilities within the system using a documentation tool called medical device interface data sheets and mitigating hazardous situations related to workflow, product usability, data integration, and the lack of effective medical device-health information technology system integration to achieve safe interoperability. Portions of the analysis of a clinical scenario for a "patient-controlled analgesia safety interlock" are provided to illustrate the method. Collecting better clinical adverse event information and proposed solutions can help identify opportunities to improve current device capabilities and interoperability and support a learning health system to improve health care delivery. Developing and analyzing clinical scenarios are the first steps in creating solutions to address vexing patient safety problems and enable clinical innovation. A Web-based research tool for implementing a means of acquiring and managing this information, the Clinical Scenario Repository™ (MD PnP Program), is described.

Using the features of the time and volumetric capnogram for classification and prediction.

Quantitative features derived from the time-based and volumetric capnogram such as respiratory rate, end-tidal PCO2, dead space, carbon dioxide production, and qualitative features such as the shape of capnogram are clinical metrics recognized as important for assessing respiratory function. Researchers are increasingly exploring these and other known physiologically relevant quantitative features, as well as new features derived from the time and volumetric capnogram or transformations of these waveforms, for: (a) real-time waveform classification/anomaly detection, (b) classification of a candidate capnogram into one of several disease classes, (c) estimation of the value of an inaccessible or invasively determined physiologic parameter, (d) prediction of the presence or absence of disease condition, (e) guiding the administration of therapy, and (f) prediction of the likely future morbidity or mortality of a patient with a presenting condition. The work to date with respect to these applications will be reviewed, the underlying algorithms and performance highlighted, and opportunities for the future noted.

Reliability and Safety Testing of a Ventilator Remote Control System Against Communication Failures and Network Disruptions.

INTRODUCTION: The need for remote ventilator control has been highlighted by the COVID-19 Public Health Emergency. Remote ventilator control from outside a patient's room can improve response time to patient needs, protect health care workers, and reduce personal protective equipment (PPE) consumption. Extending remote control to distant locations can expand the capabilities of frontline health care workers by delivering specialized clinical expertise to the point of care, which is much needed in diverse health care settings, such as tele-critical care and military medicine. However, the safety and effectiveness of remote ventilator control can be affected by many risk factors, including communication failures and network disruptions. Consensus safety requirements and test methods are needed to assess the resilience and safety of remote ventilator control under communication failures and network disruptions. MATERIALS AND METHODS: We designed two test methods to assess the robustness, usability, and safety of a remote ventilator control prototype system jointly developed by Nihon Kohden OrangeMed, Inc. and DocBox, Inc. ("the NK-DocBox system") to control the operation of an NKV-550 critical care ventilator under communication failures and network disruptions. First, the robustness of the NKV-550 ventilator was tested using a remote-control application developed on OpenICE - an open-source medical device interoperability platform - to transmit customized high-frequency and erroneous remote-control commands that could be caused by communication failures in a real-world environment. The second method utilized a network emulator to create different types and severity of network quality of service (QoS) degradation, including bandwidth throttling, network delay and jitter, packet drop and reordering, and bit errors, in the NKV-DocBox system to quantitatively assess the impact on system usability and safety. RESULTS: The NKV-550 ventilator operated as expected when remote-control commands arrived as fast as once per second. It ignored erroneous commands attempting to adjust invalid ventilation parameters. When facing commands that set the ventilation mode and parameters to invalid values, it reset the ventilation mode or parameters to default values, the safety implication of which may merit further evaluation. When any network QoS attribute (except for packet reordering) started to degrade, the NK-DocBox System experienced interference to its remote-control function, such as delays in the transmission of ventilator data and remote-control commands within the system. When the network QoS was worse than 500 ms network delay, 100 ms network jitter, 1% data drop rate, 12 Mbps minimal bandwidth, or 1e-6 bit error rate, the system became unsafe to use. For example, ventilator waveforms visualized on the remote-control application demonstrated freezes, out-of-synchronization, and moving backwards; and the connection between the ventilator and the remote-control application became unstable. CONCLUSION: The presented test methods confirmed the robustness of the NKV-550 ventilator against high-frequency and erroneous remote control, quantified the impact of network disruptions on the usability, reliability, and safety of the NK-DocBox system and identified the minimum network QoS requirements for it to function safely. These generalizable test methods can be customized to evaluate other remote ventilator control technologies and remote control of other types of medical devices against communication failures and network disruptions.

Infrared measurement of carbon dioxide in the human breath: "breathe-through" devices from Tyndall to the present day.

The ability to measure carbon dioxide (CO(2)) in the breath of a patient or capnometry, is one of the fundamental technological advances of modern medicine. I will chronicle the evolution and commercialization of mainstream capnometry based upon infrared measurement of CO(2) in the breath using information from the historical record and personal interviews with many of the developers.

The Importance of State and Context in Safe Interoperable Medical Systems.

This paper describes why "device state" and "patient context" information are necessary components of device models for safe interoperability. This paper includes a discussion of the importance of describing the roles of devices with respect to interactions (including human user workflows involving devices, and device to device communication) within a system, particularly those intended for use at the point-of-care, and how this role information is communicated. In addition, it describes the importance of clinical scenarios in creating device models for interoperable devices.

Capnographic waveforms in the mechanically ventilated patient.

A focus on patient safety has heightened the awareness of patient monitoring. The importance of clinical applications of capnography continues to grow, as reflected by the increasing number of medical societies recommending its use. Recognition of changes in the capnogram assists in clinical decision making and treatment and can increase patient safety by alerting the clinician to important situations and changes. This article describes the interpretation of capnograms and how capnogram interpretation influences airway management.

Continuous monitoring of respiratory flow and CO(2):challenges of on-airway measurements.

In this article, the challenges of simultaneous respiratory gas concentration and flow measurements in a breathing circuit are reviewed. The tradeoffs that were considered in the development of a clinically useful on-airway combination CO(2)/flow sensor are discussed as well as the applications enabled by this on-airway combination CO(2)/flow sensor.