The effective development and dissemination of the open integration for the next generation of operating rooms require a comprehensive testing environment. In this paper, we present the various challenges to be addressed in demonstration applications, and we discuss the implementation approach, the foci of the demonstration sites and the evaluation efforts. Overall, the demonstrator setups have proven the feasibility of the service-oriented medical device architecture (SOMDA) and real-time approaches with a large variety of example applications. The applications demonstrate the potentials of open device interoperability. The demonstrator implementations were technically evaluated as well as discussed with many clinicians from various disciplines. However, the evaluation is still an ongoing research at the demonstration sites. Technical evaluation focused on the properties of a network of medical devices, latencies in data transmission and stability. A careful evaluation of the SOMDA design decisions and implementations are essential to a safe and reliable interoperability of integrated medical devices and information technology (IT) system in the especially critical working environment. The clinical evaluation addressed the demands of future users and stakeholders, especially surgeons, anesthesiologists, scrub nurses and hospital operators. The opinions were carefully collected to gain further insights into the potential benefits of the technology and pitfalls in future work.

Today's landscape of medical devices is dominated by stand-alone systems and proprietary interfaces lacking cross-vendor interoperability. This complicates or even impedes the innovation of novel, intelligent assistance systems relying on the collaboration of medical devices. Emerging approaches use the service-oriented architecture (SOA) paradigm based on Internet protocol (IP) to enable communication between medical devices. While this works well for scenarios with no or only soft timing constraints, the underlying best-effort communication scheme is insufficient for time critical data. Real-time (RT) networks are able to reliably guarantee fixed latency boundaries, for example, by using time division multiple access (TDMA) communication patterns. However, deterministic RT networks come with their own limitations such as tedious, inflexible configuration and a more restricted bandwidth allocation. In this contribution we overcome the drawbacks of both approaches by describing and implementing mechanisms that allow the two networks to interact. We introduce the first implementation of a medical device network that offers hard RT guarantees for control and sensor data and integrates into SOA networks. Based on two application examples we show how the flexibility of SOA networks and the reliability of RT networks can be combined to achieve an open network infrastructure for medical devices in the operating room (OR).

Intraoperative neurophysiological monitoring (IONM) can be used to monitor the neural integrity and help the surgeon to reduce iatrogenic patient damage. We present a networked digital assistance system based on real-time IONM data. The system automatically reduces the power of active medical ablation instruments when they endanger neural structures. We integrated a nerve monitor into a real-time network of medical devices. In doing so, neurophysiological signals are available to all connected medical devices in real-time. With the IONM data a so-called function module Neuro Control calculates and controls the maximum allowed power for active instruments like an ultrasonic dissector.

We propose a novel method for the automated formal analysis of on-demand medical device networks communicating via an open communication protocol. The resulting toolbox aims at assisting operators of cross-vendor medical device networks in the complex process of conformity assessment. The method is based on the notion of timed, extended finite automata and employs existent TCTL model checking techniques by use of MATLAB and UPPAAL. We evaluate our methodology in a real-life application similar to a user experience published by the U.S. Food and Drug Admninistration. The method revealed a flaw in the connector design for the Surgical Real Time Bus of the OR.Net project.

Recent research projects [1], [2], [3] show an increasing trend from standalone medical devices to heterogeneous networks of medical devices. This poses new challenges in the field of admission and asks for novel methods to verify the network system's correct functioning and guarantee for the patients safety. The traditional, monolithic admission approach is not feasible in this case because detailed information about the concrete medical device interconnection would be needed to ensure the complete system's functioning. However, this information is unknown until the individual devices of different manufacturers are integrated into a specific medical device network. Manufacturers can only specify and guarantee the individual devices' standalone real time properties which can be distributed via ISO/IEEE 11073 medical device description format in a machine readable way. In this paper, we propose a method to automatically check whether certain real time requirements of medical device networks will be met at runtime. Our method works by building a directed, acyclic graph based on the information supplied along with the device description files as well as the specified network configuration. We map properties of the annotated information flow graph to the cyclic nature of TDMA (Time Division Multiple Access) real time networks, provide an algorithm to extract timing information from this graph and formulate three automatically verifiable constraints which are vital to the proper functioning of the network.

Below we present a new method to obtain quantitative measurements in medical images of a tracked video endoscope. Such quantitative measurements can be critical biomarkers during endoscopic diagnosis, e.g. for the classification of tumors and polyps. Size-based classifications are often achieved by mere visual estimation which can be imprecise and subjective. To this day established systems of quantitative size measurement are restricted to specific anatomical structures and require additional tools next to the endoscope. We present a system of quantitative measurement during an endoscopic procedure based on a virtual model by utilizing methods from computer vision as well as structure from motion and combining those with an optical tracking system in a novel way. Our experiments show that quantitative measurements of anatomic structures can be reliably attained by our system with an accuracy which exceeds the reported accuracy of visual estimation.

As medical devices become increasingly complex and the amount of intraoperative information produced in the operating room becomes harder to monitor by hospital staff, the demand for an open communication standard allowing the exchange of data between medical devices, equipment and computer systems is in the rise. Above technical issues, regulatory preconditions pose major challenges: European guidelines oblige medical device manufacturers to specify a list of permissible equipment for each product along with the documentation of its intended use. Operating networks of medical devices beyond their intended use necessitates documented risk management activities. The aim of this article is the development of a methodology that facilitates the detection of risks arising from the dynamic composition of medical device networks. To this end, we describe a novel machine-readable description method, allowing automated threat detection of networks composed of so-described medical devices and equipment. We evaluate our approach in a novel interconnected medical device setup and discuss possible limitations of the strategy.

Among numerous medical devices that generate noise, music is gaining increasing importance in modern operating rooms. Many surgeons perceive music as concentration enhancing during surgery. In safety critical situations instead, e.g. when a medical device emits an alarm, the additional noise exposure induced by music is considered distracting. In this article we present a novel, modular device that turns off music automatically in real time, as soon as a medical device emits an alarm. The device can easily be applied to every common alarm generating medical device and to every music source and pair of speakers, assuming that the player is connected to its speakers via a 3.5 mm audio jack cable. There is no need to modify the respective devices. The device aims at reducing the noise exposure in safety critical situations and thus protecting the patients safety against stress induced mistakes by the operating personnel. Experiments show, that it works faultlessly under common conditions regarding noise exposure in an operating room.

Through advances in technology and processing power more and more functionality can be integrated into medical devices and will find its way into the operating room (OR). New complex assistance systems can support the surgeon in performing his tasks and help to obtain better results. With an increasing number of computer assisted devices, the demand for data exchange between them is growing. If these networked systems are able to directly interfere with the patient's safety, their behaviour must be safe and deterministic at all times. Hence for an integration, such systems and their corresponding control signals have to comply with certain realtime constraints. This article analyses the requirements for an open realtime network architecture in the OR. Possible applications and their real-time requirements are introduced. These lead to the description of an open real-time architecture design based on standardized real-time Ethernet hardware. Solutions to integrate legacy devices, while maintaining their existing certifications, are further examined. Finally an experimental system set-up connecting two existing devices is demonstrated.

A vast amount of international research projects has recently been dealing with the development of an open communication standard to enhance medical device interoperability. Most approaches target a service oriented architecture based on Ethernet bus systems. Medical devices are connected to the bus and provide or consume data and applications via so-called services. For automatic discovery of device services within the network, devices possess self-descriptions (profiles) that specify the services offered by the device. These profiles are based on the international standard ISO/IEEE 11073. This article proposes a method to automatically document and test the compatibility of data in medical device networks based on their profiles. Using the new method, the time it takes to test compatibility can be significantly reduced.