Chest wall kinematics and respiratory muscle action in walking healthy humans

Abstract

We studied chest wall kinematics and respiratory muscle action in five untrained healthy men walking on a motor-driven treadmill at 2 and 4 miles/h with constant grade (0%). The chest wall volume (Vcw), assessed by using the ELITE system, was modeled as the sum of the volumes of the lung-apposed rib cage (Vrc,p), diaphragm-apposed rib cage (Vrc,a), and abdomen (Vab). Esophageal and gastric pressures were measured simultaneously. Velocity of shortening (V(di)) and power [Wdi = diaphragm pressure (Pdi) x V(di)] of the diaphragm were also calculated. During walking, the progressive increase in end-inspiratory Vcw (P < 0.05) resulted from an increase in end-inspiratory Vrc,p and Vrc,a (P < 0.01). The progressive decrease (P < 0.05) in end-expiratory Vcw was entirely due to the decrease in end-expiratory Vab (P < 0.01). The increase in Vrc,a was proportionally slightly greater than the increase in Vrc,p, consistent with minimal rib cage distortion (2.5 +/- 0.2% at 4 miles/h). The Vcw end-inspiratory increase and end-expiratory decrease were accounted for by inspiratory rib cage (RCM,i) and abdominal (ABM) muscle action, respectively. The pressure developed by RCM,i and ABM and Pdi progressively increased (P < 0.05) from rest to the highest workload. The increase in V(di), more than the increase in the change in Pdi, accounted for the increase in Wdi. In conclusion, we found that, in walking healthy humans, the increase in ventilatory demand was met by the recruitment of the inspiratory and expiratory reserve volume. ABM action accounted for the expiratory reserve volume recruitment. We have also shown that the diaphragm acts mainly as a flow generator. The rib cage distortion, although measurable, is minimized by the coordinated action of respiratory muscles.

Chest wall kinematics and respiratory muscle action in ankylosing spondylitis patients

“…Recent evidence indicates that the abdominal muscles are important contributors to ventilation in healthy humans [7][8][9][10][11]. The gradual inspiratory relaxation of the abdominal muscles during induced hyperventilation helps substantially increase the volume of the chest wall (Vcw) and lets the diaphragm act as a flow generator [8,9,11].…”

Compartmental chest wall volume changes during volitional hyperpnoea with constant tidal volume in healthy individuals

“…This should be kept in mind when comparing the present results with findings in the literature. For example, with increasing exercise intensity or CO 2 -induced hyperpnoea and concomitantly increasing ventilation, a progressive increase in end-inspiratory volumes of rib cage compartments and a decrease in the end-expiratory volume of the abdominal compartment is observed (Aliverti et al, 1997;Sanna et al, 1999;Duranti et al, 2004;Romagnoli et al, 2004;Vogiatzis et al, 2005). In the current study, these changes were present right from the start of hyperpnoea where ventilation was already required to be high.…”

Impacto de fatores externos sobre a mecânica respiratória avaliada por um modelo fotogramétrico específico: biofotogrametria

“…Studies which established references for studies on respiratory kinematics (7,(14)(15)(16)(17)(18) laid the foundation for the model of irregular quadrilaterals. Planes transverse to the references were drawn, and the extent of the chest wall was delineated from the level of the acromioclavicular joint in the upper portion to the level of the umbilicus in the lower portion ( Figure 1, Step 1).…”

“…This line was divided at the level of the xiphoid process (15) (Figure 1, Step 3) into thoracic and abdominal compartments. Other studies (16,18) permitted advancement, with additional divisions, so that each compartment became two new sub-compartments ( Figure 1, Step 2). Therefore, a plane at the level of the anterior axillary fold divided the thoracic compartment into upper and lower thoracic sub-compartments; the same occurred for the abdominal compartment, where a plane at the level of the lower angle of the 10 th rib cartilage delineated the upper and lower abdominal The areas measured using BAMER corroborated the following statements: the thoracic inspiratory areas were larger at the post-exercise with PEEP time point (p < 0.05) than at the time points without expiratory load, and this was accompanied by a reduction in the expiratory area of the abdominal compartment (p < 0.05), explained by the reduction in that of the lower abdominal sub-compartment.…”

“…Studies involving magnetometry and respiratory inductive plethysmography (18) have shown an increase in abdominal muscle recruitment during free exercise, leading to a reduction in the abdominal end-expiratory volume, accompanied by a reduction in the thoracic end-expiratory volume.…”