A method for kinematic analysis of chest wall motion is presented, based on a television-image processor that allows a three-dimensional assessment of volume change of the trunk by automatically computing the coordinates of several passive markers placed on relevant landmarks of the thorax and abdomen. The parallel computation used for the image processing allows for a real time recognition of the passive markers with the necessary accuracy. A geometric model also allows the online computation of the contribution to the chest volume by the different parts. For this purpose, the model presented here is based on 54 tetrahedrons that can be grouped into 9 compartments and 3 sections representing 1) upper thorax (mainly reflecting the action of neck and parasternal muscles and the effect of pleural pressure), 2) lower thorax (mainly reflecting the action of diaphragm and the effect of pleural and abdominal pressure), and 3) abdomen (mainly reflecting the actions of diaphragm and abdominal muscles). By this model, the volume can also be split into three vertical sections pointing out asymmetries between the right and left sides. The method is noninvasive, nonionizing, and leaves the subject maximum freedom of movement during the test, thus being suitable for routine clinical analysis. The monitoring of the subject can be prolonged in time and can be performed in different postures: standing, sitting, and supine. The method was tested on 12 healthy subjects showing its good accuracy, reliability, and reproducibility.

In nine healthy and young subject of either sex, undergoing three or four rounds of muscular exercise of increasing severity on a bicycle ergometer, the authors investigated the behavior of the lung transfer factor (DL_CO), pulmonary ventilation (V), alveolar ventilation (Va), and cardiac output (Q). In all instances they found a positive linear correlation between DL_CO and oxygen consumption (VO₂), at least up to 70 % of maximum oxygen consumption (VO_2max) (r = 0.935; p < 0.001). Dl_CO was found to increase linearly as a function of increasing V (r = 0.898; p < 0.001) and even more so of increasing Va (r = 0.919; p < 0.001). Also the relationship between Dl_CO and Q appeared linear in all subjects (r = 0.926; p < 0.001). On the other hand, individual DL_CO values showed considerable scatter at equal VO₂, V, V_A, and Q values. Among the factors responsible for the increase of DL_CO during muscular exercise, in addition to increased ventilation and cardiac output, the authors suggest the possible role of the greater desaturation of mixed venous blood and variations of hemoglobin affinity for CO.

Nine aged subjects (67 to 87 years old) and 9 young and adult persons were submitted to an exercise load (cycloergometer) varying between 1.0 to 1.5 W/kg. Tests of cardiorespiratory function, blood coagulation and fibrinolysis were carried out before and after exercise, and then after 5,15 and 60 minutes. The increase of respiratory rate was more marked in the elderly subjects than in the young and adult persons. No differences were observed with respect to the increase