Cardiac function measured by impedance cardiography is maintained during long term space flight.
- Paper number
IAC-08.A1.2.6
- Author
Dr. Jens Tank, Hannover Medical School, Germany
- Coauthor
Dr. Roman Baevsky, Institute for Biomedical Problems, Russia
- Coauthor
Dr. Irina I. Funtova, Institute for Biomedical Problems, Russia
- Coauthor
Prof. André Diedrich, Vanderbilt University, GCRC, United States
- Coauthor
Dr. Vladimir P. Katuntsev, Institute for Biomedical Problems, Russia
- Coauthor
Dr. Juergen Drescher, United States
- Coauthor
Dr. Victor M. Baranov, Institute for Biomedical Problems, Russia
- Year
2008
- Abstract
Aim Investigations of blood pressure regulation, heart rate (HR), and heart rate variability (HRV) during long term space flights aboard the ”ISS” have shown individual changes of autonomic cardiovascular control. The portable device ”Pneumocard” was developed to add information on hemodynamics in terms of stroke volume (SV) and cardiac output (CO). We tested the hypothesis that CO and SV do not decrease during long term space flight and that cardiac function is well maintained. Method The miniaturized PC-based diagnostic complex "Pneumocard" was used during in-flight experiments on ISS for autonomic function testing. ECG, photoplethysmography, respiration, impedance cardiography and seismocardiography were assessed in four male cosmonauts (flight duration six month). Recordings and analysis were made prior to the flight, monthly in-flight as well as post-flight during spontaneous respiration and during maximum voluntary inspiratory apnea. Inspiratory apnea induces a reduction in CO of up to 40 Results HR and cardiac output remained stable during flight. The values were comparable to supine pre-flight measurements. Respiratory frequency tended to decrease during flight. Maximum voluntary apnea time was prolonged early (+58±5 s) and late in-flight (+45±8 s) compared to pre-flight values. The decrease of CO and SV during apnea was attenuated late in flight (month5-7) compared to early in flight (month 1-4). CO decreased profoundly after flight in one astronaut but was comparable to pre-flight values in three astronauts mainly due to the higher HR. Conclusion Our results demonstrate that autonomic function testing aboard the ISS using “Pneumocard” is feasible and generates data of good quality for the assessment of autonomic cardiovascular control. The decrease of CO induced by maximum voluntary apnea is even less pronounced late in-flight indicating well maintained cardiac function. Hemodynamic measurements using impedance cardiography add important information in terms of individual adaptation mechanisms to zero-gravity during flight and after returning to earth. The results indicate the possibility of an individual hemodynamic management during and after flight as well as before and after extravehicular activities.
- Abstract document
- Manuscript document
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