Early recognition of pulmonary dysfunction during intramedullary orthopaedic surgery

Peri-operative partial arterial oxygen tension (PaO2) was monitored in 20 patients undergoing total hip replacement. Three distinct groups emerged on analysis of the arterial oxygen tensions. In group I there was no initial decrease in PaO2 but it rose above baseline level towards the end of the procedure. In group II there was a distinct fall in PaO2 during the acetabular and femoral stages of the operation. On termination of the procedure PaO2 had returned to baseline levels. In group III PaO2 values were significantly lower than those in group II during the acetabular and femoral stage s and decreased further at the end of the procedure. One patient in group II and 6 in group III developed postoperative pulmonary dysfunction. A progressive deterioration in PaO2 during hip replacement without recovery at end of the procedure indicates that the patient is likely to develop postoperative pulmonary dysfunction.