[Respiratory patterns induced by bent posture in COPD patients].

Three body positions were studied in order to determine their influence on the respiratory pattern in 7 subjects with chronic airflow obstruction. The positions were sitting lying back (AR), sitting with the trunk leaning forwards (AP) and standing with the trunk leaning forwards (DP). Compared to sitting lying back, sitting in the forward position favoured diaphragmatic improvement and improved the length/tension relationship of the diaphragmatic fibres and of its mechanical coupling with the thoracic cage; as a result the diaphragm took a more important part in the overall inspiratory effort thus relieving the thoracic inspiratory muscular effort. In relation to AR, the standing, leaning forward (DP) increased the end expiratory level and gave rise to the development of active expiration. This change in the usual respiratory manner enables the diaphragm to benefit on inspiration from the help bought by the restoration of the potential energy stored up in the respiratory system during the course of expiration.