Up to 30 % of astronauts exhibit post-spaceflight orthostatic hypotension due to inadequate norepinephrine release during upright posture following short duration spaceflight. We hypothesize that the (alpha)1-adrenergic agonist midodrine will be an effective countermeasure. This study is being conducted in 2 phases. The first phase is complete and consisted testing six short duration crew members. All of these subjects participated in preflight and postflight tilt testing on a control flight as well as on the test flights, where midodrine was administered after landing, 1 hour before testing. Hemodynamic variables were compared between the 2 flights. Midodrine improved stroke volume, cardiac output, systolic pressure and heart rate, without increasing vascular resistance. None of these subjects experienced orthostatic hypotension on landing day. Phase II is similar to phase I, except that midodrine is ingested in flight (near TIG) and the tilt test is performed immediately after landing on the CTV. One crewmember has completed phase II testing. This crewmember had no evidence of orthostatic hypotension or presyncope, four additional crewmembers have volunteered for this study. To date, midodrine has been shown to be a safe and effective countermeasure to post-spaceflight orthostatic hypotension.


    Access

    Access via TIB

    Check availability in my library


    Export, share and cite



    Title :

    Midodrine as a Countermeasure for Post-spaceflight Orthostatic Hypotension


    Contributors:

    Conference:

    Investigators'' Workshop ; 2007 ; League City, TX, United States


    Publication date :

    2007-01-01


    Type of media :

    Conference paper


    Type of material :

    No indication


    Language :

    English




    Midodrine as a Countermeasure to Orthostatic Hypotension Immediately After Space Shuttle Landing

    Platts, Steven H. / Stenger, Michael B. / Ribeiro, L. Christine et al. | NTRS | 2010


    Midodrine prevents orthostatic intolerance associated with simulated spaceflight

    Ramsdell, C. D. / Mullen, T. J. / Sundby, G. H. et al. | NTRS | 2001


    Mitigation of Orthostatic Hypotension in Spaceflight

    Johnson, Peter Anto / Johnson, John Christy / Mardon, Austin | TIBKAT | 2022


    Hemodynamic Effects of Midodrine After Space Flight in Astronauts Without Orthostatic Hypotension

    Platts, Steven H. / Ziegler, Michael G. / Waters, Wendy W. et al. | NTRS | 2006