Regional lung function following prosthetic hip replacement surgery.

With a Xenon133 radiospirometric technique the regional lung function was evaluated before and after prosthetic hip arthroplasty performed in the lateral decubitus position with either respirator-controlled neuroleptic anesthesia or epidural anesthesia with spontaneous breathing. Regional lung function measured in a supine position 1, 20 and 72-96 hours postoperatively revealed a reduction of the perfusion, ventilation and volume of ventilated alveoli on the dependant lung. The reduction was most pronounced immediately postoperatively, especially following respirator-controlled anesthesia. There was also an increase of pulmonary blood volume and a decrease of total lung volume in this group. The changes of lung function are probably caused by congestive atelectasis, secondary to impaired ventilation of the dependent lung. Peroperatively induced microembolism might have potentiated the effect.