[Effects of body posture on mechanical lung function in the obese patient]

The pulmonary mechanics of twelve obese patients were studied: the static and dynamic compliance, the maximum pressure of elastic recoil, and the expiratory flow curves breathing room air and a mixture of He-O2. Also analyzed were the closing capacity, the closing volume and the slope of the alveolar plateau (phase III), in the erect and supine positions. Our data confirm that the tests that explore the small airways are abnormal in the obese patients. The results obtained, allow us to assure that the pulmonary mechanics in the obese patients are affected by the change of position, as is shown by the closing volume and closing capacity when assuming the supine position when compared to orthostatism, as well as the decrease in vital capacity. These alterations were not found in non-obese patients which were used as controls.