Similar ventilation distribution in normal subjects prone and supine during tidal breathing

Rodríguez-Nieto, María Jesús; Peces-Barba, Germán; Mangado, Nicolás González; Paiva, Manuel; Verbanck, Sylvia

doi:10.1152/japplphysiol.00574.2001

Cited by 20 publications

(13 citation statements)

References 23 publications

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“…Other investigators have found no change in ventilation heterogeneity as measured by multiple‐breath nitrogen washout comparing supine versus prone positions in normal subjects (Rodriguez‐Nieto et al. ). While it is well recognized that posture affects ventilation distribution (West ), these data would suggest that it has little effect on ventilation heterogeneity.…”

Section: Discussionmentioning

confidence: 90%

Ventilation heterogeneity is increased in patients with chronic heart failure

Kee

Stuart-Andrews²,

Nilsen

et al. 2015

Physiol Rep

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In the healthy lung, ventilation is distributed heterogeneously due to factors such as anatomical asymmetry and gravity. This ventilation heterogeneity increases pathologically in conditions such as asthma, chronic obstructive lung disease, and cystic fibrosis. In chronic heart failure, lung biopsy demonstrates evidence of peripheral lung fibrosis and small airways narrowing and distortion. We hypothesized that this would lead to increased ventilation heterogeneity. Furthermore, we proposed that rostral fluid shifts when seated patients lie supine would further increase ventilation heterogeneity. We recruited 30 ambulatory chronic heart failure patients (57 ± 10 years, 83% male, left ventricular ejection fraction 31 ± 12%) as well as 10 healthy controls (51 ± 13 years, 90% male). Heart failure patients were clinically euvolemic. Subjects underwent measurement of ventilation heterogeneity using the multiple-breath nitrogen washout technique in the seated position, followed by repeat measurements after 5 and 45 min in the supine position. Ventilation heterogeneity was calculated using the lung clearance index (LCI), Sacin and Scond which represent overall, acinar, and small conducting airway function, respectively. Lung clearance index (9.6 ± 1.2 vs. 8.6 ± 1.4 lung turnovers, P = 0.034) and Scond (0.029 ± 0.014 vs. 0.006 ± 0.016/L, P = 0.007) were higher in the heart failure patients. There was no difference in Sacin (0.197 ± 0.171 vs. 0.125 ± 0.081/L, P = 0.214). Measures of ventilation heterogeneity did not change in the supine position. This study confirms the presence of peripheral airway pathology in patients with chronic heart failure. This leads to subtle but detectable functional abnormalities which do not change after 45 min in the supine position.

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Section: Discussionmentioning

confidence: 90%

Ventilation heterogeneity is increased in patients with chronic heart failure

Kee

Stuart-Andrews²,

Nilsen

et al. 2015

Physiol Rep

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“…However, Rodríguez‐Nieto et al. () showed no difference in FRC and tidal breathing in prone and supine positions; thus, it is unlikely that volume expansion results from a mechanical effect.…”

Section: Discussionmentioning

confidence: 97%

Influence of graviceptor stimulation initiated by off‐vertical axis rotation on ventilation

Kuldavletova

Marie

Denise

et al. 2018

Experimental Physiology

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It has been suggested that the otolith system is involved in the physiological response to changes in body orientation with respect to gravity. In studies on animals, an otolith-respiratory reflex has been observed, but data on humans are scarce and inconclusive, mainly because pure otolithic stimulation is difficult to produce in humans. To assess the otolithic-respiratory reflex in humans, we used an off-vertical axis rotation (OVAR) that produces periodic and pure stimulation of graviceptors. The inspiratory flow was measured during earth vertical axis rotation (EVAR, control conditions) and OVAR in 21 subjects. To distinguish the effects of the labyrinthine and non-labyrinthine graviceptors on ventilation, these measurements were repeated with two different static head positions: head turned leftward and rightward in yaw. The velocity of rotation was individually selected to match spontaneous breathing rate (mean 11.4 cycles min , 0.19 Hz). Average ventilatory flow was higher in OVAR than in EVAR, as was tidal volume. In OVAR, the transition between inspiration and expiration occurred mainly in the forward pitch position. The phase of this transition in most subjects was driven mostly by the body position rather than by the head position, suggesting that respiratory modifications during OVAR mainly involved non-labyrinthine receptors. However, the study demonstrated a high intersubject variability both in the ability of OVAR to synchronize breathing and in the influence of labyrinthine stimulation. We conclude that the respiratory response to changes in orientation of the body with respect to the vertical involves labyrinthine and non-labyrinthine stimulation, with the gain of each signal varying individually.

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“…Perfusion [30 ]and ventilation distribution [31, 32 ]were found to be more homogeneous at prone than supine position but also similar in both recumbent postures [31,32,33]. However, ventilation-perfusion measurements consistently showed a similar distribution between prone and supine postures [32, 34].…”

Section: Discussionmentioning

confidence: 99%

Effect of Postural Variations on Carbon Monoxide Diffusing Capacity in Healthy Subjects and Patients with Chronic Obstructive Pulmonary Disease

et al. 2008

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Background: The scientific literature does not supply enough information about the effects of postural changes on diffusing lung capacity for carbon monoxide (DL_CO) in patients with chronic obstructive pulmonary disease (COPD), in particular regarding the prone position. Objectives: We evaluated posture-related changes in DL_CO in healthy subjects and in COPD patients in order to especially assess how prone posture affects gas exchange. Methods: In this cross-sectional study, DL_CO was measured in 10 healthy subjects and 30 COPD patients in standing, seated, supine and prone positions. Results: In healthy individuals, DL_CO tended to improve from the upright to the supine position (21.42 ± 2.90 and 26.07 ± 5.11 ml/min/mm Hg, respectively); in the same group, changing the position from upright to prone also caused significant improvements in DL_CO (absolute value, 21.42 ± 2.90 vs. 24.80 ± 4.39 ml/min/mm Hg, p < 0.05, or percent of predicted, 78.58 ± 11.12 vs. 91.44 ± 13.23, p < 0.05) and in DL_CO proportional to alveolar volume (DL_CO/VA; 4.52 ± 0.57 vs. 5.66 ± 1.48 ml/min/mm Hg/l, p < 0.05). No significant differences in DL_CO have been observed in COPD patients from the standing to the prone position. Multivariate linear regression models showed that the posture-related changes in DL_CO, DL_CO expressed as percent of predicted and in DL_CO/VA are directly correlated with the transition from upright/sitting to supine/prone. Conclusions: In healthy subjects, the effect of postural changes on DL_CO could be explained by a more homogeneous perfusion, whereas the lack of variations in COPD patients could be attributed to the increased rigidity of lung capillaries, which could represent an early sensitive marker of damage of the alveolar capillary interface in these patients.

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Similar ventilation distribution in normal subjects prone and supine during tidal breathing

Cited by 20 publications

References 23 publications

Ventilation heterogeneity is increased in patients with chronic heart failure

Ventilation heterogeneity is increased in patients with chronic heart failure

Influence of graviceptor stimulation initiated by off‐vertical axis rotation on ventilation

Effect of Postural Variations on Carbon Monoxide Diffusing Capacity in Healthy Subjects and Patients with Chronic Obstructive Pulmonary Disease

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