Midodrine prevents post-space flight orthostatic intolerance when testing is conducted in a controlled laboratory setting within 2-4 hours after Space Shuttle landing. It is unknown if midodrine is as effective during re-entry and immediately following landing. METHODS: Cardiovascular responses to 10 minutes of 80 head-up tilt in five male astronauts were compared before and immediately after Space Shuttle missions. Preflight tests were conducted in the Johnson Space Center Cardiovascular Laboratory without midodrine. Post-flight testing was performed in the Crew Transport Vehicle on the Space Shuttle runway within 60 minutes of landing; midodrine was self-administered before re-entry. Survival analysis was performed (Gehan-Breslow test) to compare presyncope rates pre- to post-flight. Cardiovascular responses (last minute standing minus supine) to tilt before and after space flight were compared using paired t-tests. RESULTS: Midodrine did not prevent post-flight orthostatic hypotension in two of the five astronauts, but the rate of presyncope across the group did not increase (p=0.17) from pre- to post-flight. Also, although the change in heart rate from supine to the last minute of standing was not affected by space flight, systolic blood pressure decreased more (p=0.05) and diastolic blood pressure tended to decrease (p=0.08) after space flight. CONCLUSIONS: Accurate interpretation of the current results requires that similar data be collected in control subjects (without midodrine) on the CTV. However, drug interaction concerns with commonly used anti-emetics and potentiation of prolonged QTc intervals observed in long duration astronauts make the routine use of midodrine for immediate post-flight orthostatic hypotension unlikely. 2


    Access

    Access via TIB

    Check availability in my library


    Export, share and cite



    Title :

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



    Publication date :

    2010-01-01


    Type of media :

    Miscellaneous


    Type of material :

    No indication


    Language :

    English




    Midodrine as a Countermeasure for Post-spaceflight Orthostatic Hypotension

    Platts, Steven H. / Ziegler, Michael G. / Waters, Wendy W. et al. | NTRS | 2007


    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


    Orthostatic hypotension

    Shannon, J. R. / Robertson, D. | NTRS | 1997


    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