Optimizing medical resources for spaceflight using the integrated medical model

Introduction: Efficient allocation of medical resources for spaceflight is important for crew health. The Integrated Medical Model (IMM) was developed to estimate medical event occurrences, mitigation, and resource requirements. An optimization module was created for IMM that uses a systematic process of elimination and preservation to maximize crew health outcomes subject to resource constraints. Methods: A maximum medical kit is identified and resources are eliminated according to their relative impact on outcomes of interest. Additional steps allow opportunities for resources to be added back into the medical kit if possible. The effectiveness of the module is demonstrated under six alternative mission profiles by optimizing the medical kit to maximize the expected Crew Health Index (CHI), and comparisons are made with minimum and maximum kits. Results: The optimum and maximum kits had similar expected CHI, but CHI was more variable for the optimum kit. The maximum kit resulted in the best outcomes, but required at least 13.7 times the mass of the optimum kit and 26.6 times the volume. The largest difference in mean CHI between the optimum and maximum kits occurred for four crewmembers on a 180-d mission (91.1% vs. 95.4%). Conclusions: The optimization module may be used as an objective tool to assist with the efficient allocation of medical resources for spaceflight. The module provides a flexible algorithm that may be used in conjunction with the IMM model to assist in medical kit requirements and design.