We studied the respiratory output in five subjects exposed to parabolic flights [gravity vector 1, 1.8 and 0 gravity vector in the craniocaudal direction (G(z))] and when switching from sitting to supine (legs bent at the knees). Despite differences in total respiratory compliance (highest at 0 G(z) and in supine and minimum at 1.8 G(z)), no significant changes in elastic inspiratory work were observed in the various conditions, except when comparing 1.8 G(z) with 1 G(z) (subjects were in the seated position in all circumstances), although the elastic work had an inverse relationship with total respiratory compliance that was highest at 0 G(z) and in supine posture and minimum at 1.8 G(z). Relative to 1 G(z), lung resistance (airways Plus lung tissue) increased significantly by 52% in the supine but slightly decreased at 0 G(z). We calculated, for each condition, the tidal volume changes based on the energy available in the preceding phase and concluded that an increase in inspiratory muscle output occurs when respiratory load increases (e.g., going from 0 to 1.8 G(z)), whereas a decrease occurs in the opposite case (e.g., from 1.8 to 0 G(z)). Despite these immediate changes, ventilation increased, going to 1.8 and 0 G(z) (up to approximate to23%), reflecting an increase in mean inspiratory flow rate, tidal volume, and respiratory frequency, while ventilation decreased (approximately -14%), shifting to supine posture (transition time similar to15 s). These data suggest a remarkable feature in the mechanical arrangement of the respiratory system such that it can maintain the ventilatory output with small changes in inspiratory muscle work in face of considerable changes in configuration and mechanical properties.

Dellaca, R., Bettinelli, D., Kays, C., Techoueyres, P., Lachaud, J., Vaida, P., et al. (2004). Effect of changing the gravity vector on respiratory output and control. JOURNAL OF APPLIED PHYSIOLOGY, 97(4), 1219-1226 [10.1152/japplphysiol.00845.2003].

Effect of changing the gravity vector on respiratory output and control

MISEROCCHI, GIUSEPPE ANDREA
2004

Abstract

We studied the respiratory output in five subjects exposed to parabolic flights [gravity vector 1, 1.8 and 0 gravity vector in the craniocaudal direction (G(z))] and when switching from sitting to supine (legs bent at the knees). Despite differences in total respiratory compliance (highest at 0 G(z) and in supine and minimum at 1.8 G(z)), no significant changes in elastic inspiratory work were observed in the various conditions, except when comparing 1.8 G(z) with 1 G(z) (subjects were in the seated position in all circumstances), although the elastic work had an inverse relationship with total respiratory compliance that was highest at 0 G(z) and in supine posture and minimum at 1.8 G(z). Relative to 1 G(z), lung resistance (airways Plus lung tissue) increased significantly by 52% in the supine but slightly decreased at 0 G(z). We calculated, for each condition, the tidal volume changes based on the energy available in the preceding phase and concluded that an increase in inspiratory muscle output occurs when respiratory load increases (e.g., going from 0 to 1.8 G(z)), whereas a decrease occurs in the opposite case (e.g., from 1.8 to 0 G(z)). Despite these immediate changes, ventilation increased, going to 1.8 and 0 G(z) (up to approximate to23%), reflecting an increase in mean inspiratory flow rate, tidal volume, and respiratory frequency, while ventilation decreased (approximately -14%), shifting to supine posture (transition time similar to15 s). These data suggest a remarkable feature in the mechanical arrangement of the respiratory system such that it can maintain the ventilatory output with small changes in inspiratory muscle work in face of considerable changes in configuration and mechanical properties.
Articolo in rivista - Articolo scientifico
microgravity; respiratory mechanics; respiratory control; pulmonary ventilation
English
ott-2004
97
4
1219
1226
none
Dellaca, R., Bettinelli, D., Kays, C., Techoueyres, P., Lachaud, J., Vaida, P., et al. (2004). Effect of changing the gravity vector on respiratory output and control. JOURNAL OF APPLIED PHYSIOLOGY, 97(4), 1219-1226 [10.1152/japplphysiol.00845.2003].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/2825
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