Computational modeling of orthostatic intolerance for travel to Mars

Abstract

Astronauts in a microgravity environment will experience significant changes in their cardiopulmonary system. Up until now, there has always been the reassurance that they have real-time contact with experts on Earth. Mars crew however will have gaps in their communication of 20 min or more. In silico experiments are therefore needed to assess fitness to fly for those on future space flights to Mars. In this study, we present an open-source controlled lumped mathematical model of the cardiopulmonary system that is able simulate the short-term adaptations of key hemodynamic parameters to an active stand test after being exposed to microgravity. The presented model is capable of adequately simulating key cardiovascular hemodynamic changes—over a short time frame—during a stand test after prolonged spaceflight under different gravitational conditions and fluid loading conditions. This model can form the basis for further exploration of the ability of the human cardiovascular system to withstand long-duration space flight and life on Mars.

Potential Biomarkers of Resilience to Microgravity Hazards in Astronauts

“…Microgravity exposure during spaceflight induces a constellation of cardiovascular adaptations that can lead to orthostatic intolerance [ 58 ] and cardiac deconditioning [ 59 ]. Orthostatic intolerance, characterized by an inability to maintain blood pressure and cerebral perfusion upon assuming an upright posture, affects up to 80% of astronauts returning from long-duration missions [ 60 ]. The mechanisms underlying post-spaceflight orthostatic intolerance are multifactorial and include hypovolemia, altered autonomic control, and reduced vascular responsiveness [ 61 ].…”

Computational modeling of heart failure in microgravity transitions

“…This project built upon the work of van Loon, Steins (van Loon et al, 2022), who established a controlled 21-compartment mathematical model of the cardiovascular system. In short, the model consists of four time-varying elastic heart compartments, 5 intra-thoracic compartments, two upperbody compartments, and eight lower-body compartments.…”

“…Given the absence of available data on patients with heart failure in microgravity, the use of mathematical simulations is deemed appropriate to study this topic. Mathematical models have proven valuable in space medicine for predicting physiological changes that occur after exposure to microgravity (Wieling et al, 2002;Mohammadyari et al, 2021;van Loon et al, 2022). Therefore, the primary aim of this study is to simulate the effects and assess the risks associated with microgravity transitions for individuals with heart failure.…”

Computational simulations of the effects of gravity on lymphatic transport

“…Detailed models of lymphatic networks, complete with valves have been described ( 27 ), and valve mechanics have been examined in detail using explicit mechanics and fluid dynamics ( 28 ). Other models have examined the effects of gravity on CSF pressures ( 29 ) and the effects of microgravity on systemic fluid redistribution using whole-body compartment-based modeling ( 30 ). In general, these models examine transport without consideration of the mechanobiological mechanism that control lymphatic contractions.…”