Validation of a newly developed LBNP-system
- Paper number
IAC-06-A2.P.07
- Author
Dr Thais Russomano, Microgravity Laboratory/PUCRS, Brazil
- Coauthor
Dr. Dario Francisco Azevedo, Microgravity Laboratory/PUCRS, Brazil
- Coauthor
Mr. Felipe Falcao, Microgravity Laboratory/PUCRS, Brazil
- Coauthor
Mr. Celso dos Santos, Microgravity Laboratory/PUCRS, Brazil
- Coauthor
Dr. Luis Beck, Deutsches Zentrum fur Luft und Raumfahrt e.V. (DLR), Germany
- Year
2006
- Abstract
Introduction: An LBNP box was developed, consisting of a cylindrical structure of five carbon steel ribs wrapped with high pressure resistant vinyl (0.6mm thick). The couch was supported on wheels to ease moving the subject into and out of the box. A custom-made skirt was secured around the subject’s waist by an adjustable belt. The rigid end of the cylinder carried solenoid controlled air inlet and outlet valves. Air flowing into the cylinder was distributed by a pair of perforated pipes. Transducers sensing the pressure, airflow, humidity and temperature within the box controlled the inlet and outlet valves, to maintain box pressure at the pre-selected value (range 0 to 45mmHg). Method: Five healthy male subjects participated in the test, which consisted of 20min baseline period (supine), 10min at -30mmHg and 5min of recovery. The ECG and digital artery pressure were recorded. Results: An airflow of 12.5 L/s was used to keep the LBNP box pressure at -30.1mmHg, temperature at 24ºC and humidity at 40%. The trolleys allowed very easy movement of the instrumented subject. A high standard seal was achieved between the subject and the box. Heart rate, diastolic and mean arterial blood pressures remained unchanged during test. Systolic blood pressure decreased from 104.4 mmHg to 101.5 mmHg. Calculated SV and CO from the arterial blood pressure trace decreased from 90 ml and 6.8 L/min to 60.5 ml and 4.2 L/min, respectively. Calculated TPR increased from 985.9 dyn.s.cm-5 to 1544 dyn.s.cm-5 during session. Conclusion: The physiological responses were in accordance with other published studies. The trolley and sealing systems proved to be efficient. The environmental control system of the LBNP box maintained the negative pressure, temperature and humidity constant throughout tests.
- Abstract document
- Manuscript document
IAC-06-A2.P.07.pdf (🔒 authorized access only).
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