[Elastic recoil pressure in radiation induced injury of the lung]

The study was carried out on 34 females, age range 31-62 years, mean 46 years. It was conducted in the early phase, 3 months after introduction of the radiotherapy with X-rays. The results were compared with the initial values measured immediately after surgical removal of the tumour. The irradiation dose was 40 Gy to the sternum area and 35 Gy to the middle part of the axilla. Volume and capacity indices, bronchial resistance, small airway function parameters and mechanical properties of the lungs were studied. In the group of younger females (age < 46 years) a significant increase of the retraction index was noted (RC = P.TLC: TLC) following radiotherapy and a coexistent decrease of thoracic gas volume (TGV). In the whole group 13 patients reacted to radiotherapy with a left shift of the V/Pel curve, demonstrating an increase of elastic recoil. This group of patients also showed a marked decrease of TGV. These observations demonstrate that in a part of the patients treated with X radiotherapy a new equilibrium instated between elastic recoil pressure and lung capacity.