Differential changes of lung diffusing capacity and  tissue volume in hypergravity

Rohdin, Malin; Linnarsson, Dag

doi:10.1152/japplphysiol.01271.2001

Cited by 21 publications

(33 citation statements)

References 18 publications

(28 reference statements)

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“…For very shortlasting microgravity, Vaida et al (30) showed that both DL NO and the membrane component of DL CO were increased by Ͼ40%. Furthermore, Rohdin et al (21) showed that DL CO is decreased by 21% at two times normal gravity (2 G) and by 34% at three times normal gravity (3 G) (21). We therefore exposed healthy subjects to both decreases and increases of gravity and studied their exhaled NO.…”

mentioning

confidence: 96%

Microgravity decreases and hypergravity increases exhaled nitric oxide

Karlsson

Kerckx

Gustafsson

et al. 2009

Journal of Applied Physiology

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Inhalation of toxic dust during planetary space missions may cause airway inflammation, which can be monitored with exhaled nitric oxide (NO). Gravity will differ from earth, and we hypothesized that gravity changes would influence exhaled NO by altering lung diffusing capacity and alveolar uptake of NO. Five subjects were studied during microgravity aboard the International Space Station, and 10 subjects were studied during hypergravity in a human centrifuge. Exhaled NO concentrations were measured during flows of 50 (all gravity conditions), 100, 200, and 500 ml/s (hypergravity). During microgravity, exhaled NO fell from a ground control value of 12.3 +/- 4.7 parts/billion (mean +/- SD) to 6.6 +/- 4.4 parts/billion (P = 0.016). In the centrifuge experiments and at the same flow, exhaled NO values were 16.0 +/- 4.3, 19.5 +/- 5.1, and 18.6 +/- 4.7 parts/billion at one, two, and three times normal gravity, where exhaled NO in hypergravity was significantly elevated compared with normal gravity (P

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mentioning

confidence: 96%

Microgravity decreases and hypergravity increases exhaled nitric oxide

Karlsson

Kerckx

Gustafsson

et al. 2009

Journal of Applied Physiology

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“…Cardiac effects of hypergravity include a 1 cm downward movement of the heart at 2.5 G (Rushmer 1947) and a 70% increase in its stroke work at 2 G compared to 1 G (Howard 1965). SV decreases by 20% whereas decreases in ð _ QÞ range from slight to large in different reports (Lindberg et al 1960;Rohdin and Linnarsson 2002;Rohdin et al 2004). These reports of SV and ð _ QÞ changes are in accordance with our results.…”

Section: Effect Of 2 G Without Anti-g Suit Inflationmentioning

confidence: 83%

“…For example, stroke volume (SV) is not constant during all phases of a parabola (increased during 0 G and decreased during 1.5-2 G [Johns et al 1994;Rohdin and Linnarsson 2002]), which renders difficult a comparison between cardiovascular data (Linnarsson et al 1996) and the study of cardio-pulmonary interactions (Lauzon et al 1997(Lauzon et al , 1998 at 0, 1 and 2 G.…”

Section: Introductionmentioning

confidence: 99%

Cardiovascular effects of anti-G suit inflation at 1 and 2 G

Montmerle

Linnarsson

2005

Eur J Appl Physiol

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We sought to determine to which pressure a full-coverage anti-G suit needs to be inflated in order to obtain the same stroke volume during a brief exposure to twice the normal gravity (2 G) as that at 1 G without anti-G suit inflation. Nine sitting subjects were studied at normal (1 G) and during 20 s of exposure to 2 G. They wore anti-G suits, which were inflated at both G-levels to the following target pressures: 0, 70, 140 and 210 mmHg. Stroke volume was computed from cardiac output, which was measured by rebreathing. Heart rate and mean arterial pressure at heart level were recorded. Inflation to 70 mmHg compensated for the decrease in stroke volume and cardiac output caused by hypergravity. Mean arterial pressure at heart level was comparable at 1 G and at 2 G and increased gradually and similarly with inflation (P<0.001) at both gravity levels. Thus, anti-G suits act by increasing both preload and afterload but the two effects counteract each other in terms of cardiac output, so that cardiac output at 2 G is maintained at its 1 G level. This effect is reached already at 70 mmHg of inflation. Greater inflation pressure further increases mean arterial pressure at heart level and compensates for the increased difference in hydrostatic pressure between heart and head in moderate hypergravity.

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“…Rohdin and Linnarson found increased lung tissue volume in healthy subjects during 2 and 3 G z centrifugation in a sitting position. Furthermore, they reanalyzed the parabolic flight data of Vaida et al and noted an increase in lung tissue volume in weightlessness (Vaida et al 1997; Rohdin and Linnarsson 2002). Vaida had performed the experiment during parabolic flights in the former European Caravel parabolic flight airplane under a hypobaric ambient pressure of 793 mbar.…”

Section: Discussionmentioning

confidence: 99%

Interactions of the human cardiopulmonary, hormonal and body fluid systems in parabolic flight

et al. 2014

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healthy subjects in the standing position while they were in parabolic flight at 0 and 1.8 g z . Plasma volume (PV) and fluid regulating blood hormones were determined five times over the flight day. Eleven out of the 18 subjects were subjected to an identical test protocol in a hypobaric chamber in ambient conditions comparable to parabolic flight. Results cI rb in 0 g z decreased significantly during flight (early, 5.139 ± 1.326 l/min; late, 4.150 ± 1.082 l/ min) because of a significant decrease in heart rate (Hr) (early, 92 ± 15 min −1 ; late, 78 ± 12 min −1), even though the stroke volume (SV) remained the same. HH produced a small decrease in the PV, both in the hypobaric chamber and in parabolic flight, indicating a dominating HH effect without a significant effect of gt on PV (−52 ± 34 and −115 ± 32 ml, respectively). Pulmonary tissue volume decreased in the HH conditions because of hypoxic pulmonary vasoconstriction (0.694 ± 0.185 and 0.560 ± 0.207 ml) but increased at 0 and 1.8 g z in parabolic flight (0.593 ± 0.181 and 0.885 ± 0.458 ml, respectively), indicating that cardiac output and arterial blood pressure rather than HH are the main factors affecting pulmonary vascular regulation in parabolic flight. Conclusion HH and gt each lead to specific responses of the cardiovascular system in parabolic flight. Whereas HH seems to be mainly responsible for the PV decrease in flight, gt overrides the hypoxic pulmonary vasoconstriction induced by HH. this finding indicates the need for careful and individual medical examination and, if necessary, health status improvement for each individual considering a parabolic flight, given the effects of the combination of HH and gt in flight.Keywords Inert gas rebreathing · Weightlessness · Hypobaric hypoxia · Hypobaric chamber · gravity AbstractPurpose commercial parabolic flights accessible to customers with a wide range of health states will become more prevalent in the near future because of a growing private space flight sector. However, parabolic flights present the passengers' cardiovascular system with a combination of stressors, including a moderately hypobaric hypoxic ambient environment (HH) and repeated gravity transitions (gt). thus, the aim of this study was to identify unique and combined effects of HH and gt on the human cardiovascular, pulmonary and fluid regulation systems. Methods cardiac index was determined by inert gas rebreathing (cI rb ), and continuous non-invasive finger blood pressure (FBP) was repeatedly measured in 18 communicated by guido Ferretti.Electronic supplementary material the online version of this article

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Differential changes of lung diffusing capacity and tissue volume in hypergravity

Cited by 21 publications

References 18 publications

Microgravity decreases and hypergravity increases exhaled nitric oxide

Microgravity decreases and hypergravity increases exhaled nitric oxide

Cardiovascular effects of anti-G suit inflation at 1 and 2 G

Interactions of the human cardiopulmonary, hormonal and body fluid systems in parabolic flight

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