Medical monitoring in long-term space missions

The following principles, derived from the experience of medical support during past spaceflights, can provide a basis for a system of health monitoring and diagnosis during long-term and interplanetary missions: a system of preflight medical screening; medical screening on a systemic basis, which may include purposeful diagnosis in subsystems following the method of hierarchic structure; use of an individual approach; correction of the medical program with respect to the space crew status; assessment of the interrelations of the entire complex of parameters; utilization of the methods of correlation, classification and identification to elicit interrelations between different functions; evaluation of shifts in body functions and their adequacy to ambient conditions; continuity of medical examinations during all pre-flight stages, during flight and after completion of flight; analysis of information and anamnestic data by means of data bases; confidentiality of medical conclusions. Discussed are a classification of unfavorable microgravity-related syndromes, possible impairments due to abnormal situations, and some approaches to the prediction of the risk of various diseases, in relation to the construction of a conceptual diagnostic model for interplanetary missions. In the interest of medical monitoring special significance is attributed to the knowledge of individual norms for each crew member and of his unique peculiarities. Such data can be compiled by means of statistical analysis (single and multidimensional analysis) of the results of medical examinations and of observations during selection, training and tests. Selection of necessary physiological parameters, functional loads and data processing techniques which can be used in combination with other data sources for inflight diagnosis should be based on the following principles: the use of informative, non-invasively registered parameters and functional tests to reveal adverse states or most probable diseases; the possibility to assess the dynamics of physiological parameters and the status of the regulatory systems, and to predict possible developments in the body; the possibility to check the efficiency of countermeasures; the possibility to differentiate a physiological state adapted to the current environment from a pathological state; the possibility to differentiate between specific and non-specific reactions; the possibility to differentiate defensive, adaptive or compensatory phenomena from pathological manifestations. This paper describes the application of single- and multidimensional, statistical methods to process diagnostic information, to reduce the vector dimension of the chosen parameters, and to classify and identify individual and crew physiological standards providing the ability to assign an individual to a suitable team. Thus it will be possible to acquire comprehensive and statistically reliable information in compact format, and thus to perform a more incisive analysis and diagnosis of various states by comparing them with the baseline preflight data. These theoretical considerations constitute the basis for a conceptual model for medical diagnosis in long-term orbital and interplanetary missions. The paper contains a section dealing with the practical aspects of medical monitoring and diagnostic examinations during Mir missions. The program of medical monitoring for long-term Mir missions incorporates on-line monitoring during intravehicular and extravehicular activities, routine daily examinations, periodic extensive medical examinations accomplished on schedule or an indication. The Mir program includes cardiovascular investigations at rest and during functional loading, testing of the cosmonaut muscular systems, validation of the standard training protocols, occasional blood and urine analysis, incl. serum immunoglobulins, and blood cell counts. (ABSTRACT TRUNCATED)