Abnormalities of chest wall motion in patients with chronic airflow obstruction

Forty patients with severe chronic stable airflow obstruction and hyperinflation were studied to assess patterns of abnormal chest wall motion and their frequency. Dimensional changes were measured during tidal breathing, four pairs of magnetometers being used to record anteroposterior diameters of ribcage and abdomen and two lateral diameters of the ribcage. Chest wall movements were qualitatively normal in only five patients. Three main types of abnormality were found and 13 subjects had two or more abnormal patterns. Lateral ribcage paradox was present in 31 of the 40 patients and was recognised clinically in all except one. Inspiratory indrawing of the lower sternum was recorded in 12 patients, paradoxical inspiratory motion of the abdomen was present in four patients and in six there was a biphasic expiratory pattern of abdominal movement. Analysis of variance showed no significant group differences in severity of airflow obstruction or hyperinflation between the patients with qualitatively normal motion and those with different types of abnormal motion. Relationships between the tidal displacement of each dimension and severity of airflow obstruction and hyperinflation were examined. In general, patients with more severe hyperinflation showed less abdominal movement and those with severe airflow obstruction had less lateral expansion of the ribcage, but the correlations were weak. It is concluded that abnormal motion of the chest wall is very common in patients with airflow obstruction and hyperinflation, that clinical recognition of abnormal motion other than lateral ribcage paradox is easily overlooked, and that quantitative relationships between abnormal motion and disease severity are weak.