The Integrated Medical Model (IMM) is designed to identify and quantify crew health risks during flight and to evaluate the effectiveness of in-flight mitigation strategies. The IMM integrates terrestrial and space flight evidence bases to quantify the probability and the consequences of in-flight medical risks using Monte Carlo simulations. Utilizing well accepted scenario driven techniques, such as probabilistic risk analysis, as a guide, IMM generates a set of quantitative measures, such as mission time lost, probability of crew evacuation, and probability of loss of crew life, to enable decision makers to make objective assessment of crew health and mission outcomes with respect to our current level of knowledge.

The current IMM can be used to optimize in-flight medical system capabilities, manage science and technology development portfolios, prioritize crew medical training, and support a variety of “what if” scenarios posed by mission planners. The latest version of the model, IMM 3.0, includes a SQL database and Reference Manager central library, which quantify and document all the clinical evidence used by the IMM.

This interdisciplinary research effort included the establishment of a conceptual framework, the development of an extensive input dataset and SQL database, the development of external models, the creation of simulation and optimization model software, and the design and implementation of novel verification, validation, and configuration management processes.

OBJECTIVES

The IMM Project was tasked to develop an evidence-based, probabilistic decision support tool and integrate the tool in the decision making processes of customers within the Space Life Sciences Directorate (SLSD). The five key objectives of the IMM Project support these overarching goals: 1) develop a software-based, stochastic decision support tool useful to clinical stakeholders and medical mission planners; 2) develop a knowledge management tool for the clinical evidence used by the model; 3) update the medical risk estimates of the Probabalistic Risk Assessment model used by the International Space Station (ISS) Program; 4) develop the ability to optimize the mass and volume for an in-flight medical system and specified level of risk; and 5) help close the communication gaps among science, clinical operations, and engineering communities.

The ability to categorize health threats according to crew physiology, crew activities, mission tempo, and mission environment enables prioritized training, space flight systems development, and procedures that result in positive health and mission impacts. IMM can provide a defensible position for making cost-effective decisions regarding crew health, and will help achieve mission success by focusing limited funds on the most relevant health care policies, protocols, and technologies.

Three key tools created by the IMM Project increase SLSD knowledge management, research, and operational capabilities: 1) IMM Central Library - The IMM Central Library houses all citations and references used to form the clinical basis for each medical condition represented in the IMM. This central library creates the foundation for the SLSD Enterprise-wide Library Solution; 2) IMM Database - The IMM Database is accessible by the SLSD science and clinical operations community. Custom-designed reports can be tailored for each user while automatic notifications will ensure they are aware of the latest additions or alternations; and 3) IMM - The evidence-based, analytic representation of in-flight crew health risk -- in the context of a specific mission and crew profile -- provides an unprecedented capability to communicate clinical risk in engineering-centric programs. The IMM also provides an objective foundation for mission planning dialogue based on evidence and all available relevant data sources.

The Integrated Medical Model (IMM) is a decision support tool useful to mission planners and medical system designers in assessing risk and designing medical systems for specified space flight missions. The IMM provides an evidence–based approach to optimize medical resources and minimize risk within space flight operational constraints.

Methods

The mathematical relationships among mission and crew profiles, medical condition incidence data, in-flight medical resources, potential crew functional impairments, and clinical end-states are established to determine probable mission outcomes. Stochastic computational methods are used to forecast probability distributions of crew health and medical resource utilization, as well as estimates of medical evacuation and loss of crew life. The IMM has been used in support of the International Space Station (ISS) medical kit re-design, the medical component of the ISS Probabilistic Risk Assessment, and the development of the Constellation Medical Conditions List. The IMM will also be used to refine medical requirements for the Constellation program.

Discussion

The IMM outputs for ISS and Constellation Design Reference Missions will be presented to demonstrate the potential of the IMM in risk assessment, mission planning and medical system design. The implementation of the IMM verification and validation plan will be reviewed. Additional planned capabilities of the IMM, including optimization techniques and the inclusion of a mission timeline will be discussed.

Conclusions

Given the space flight constraints of mass, volume, and crew medical training, the IMM is a valuable risk assessment and decision support tool for medical system design and mission planning.

[Note: project added to Task Book 11/2009 when received project information]