Clinical and physiological associations of some physical signs observed in patients with chronic airways obstruction.

A study of the relation between physical signs and the clinical and physiological pattern of chronic lung disease with obstruction has been carried out on 24 patients with varying degrees of airways obstruction. One sign (the forced expiratory time) was a direct reflection of the obstruction , but a number of other signs which also correlated significantly with the specific airway conductance were probably related to secondary effects on lung volume (increased resonance), disordered pattern of muscle action (tracheal tug and use of accessory muscles) or to excessive swings of intrathoracic pressure (excavation of supraclavicular fossae). Other signs which are regularly present but which did not correlate significantly with the severity of the airways obstruction were often related to other factors such as age or duration of symptoms (tracheal length). The difficulties in deciding the origin of other signs such as wheezes (rhonchi) or costal paradox are discussed. In previous publications we have described certain physical signs which were felt to be of use in assessing airways obstruction (Campbell, 1969) and we have shown that these signs possess a degree of observer variation similar to that of other physical signs (Godfrey, Edwards, Camp-bell, Armitage, and Oppenheimer, 1969). We have now studied the clinical and physiological associations of these signs. METHODS Observations were made on 24 patients in either the wards or outpatient clinics at Hammersmith Hospital. All the patients were known to have stable airways obstruction from previous tests of pulmonary function and there was a wide variation of severity as judged by clinical and physiological criteria. The patients were examined while lying on a couch with the back rest raised to 45'. Two of us (R. examined them independently in the manner described previously (Campbell, 1969; Godfrey et al., 1969). The findings of the two observers were then compared and, if any differences arose, the observers were invited to examine the patient together to reach an agreed conclusion, with S. G. acting as arbitrator. A series of pulmonary function tests was performed on the same day as the examination. The forced expiratory volume in one second (FEV1.o) and the relaxed vital capacity (VC) were determined by the method of Freedman and Prowse (1966) using a dry spirometer. Lung volumes, airways resistance and specific conductance were determined in the body plethysmograph by the method of Briscoe and Dubois (1958). The specific conductance (SGaw) is airway conductance divided by thoracic gas …