Arterial oxygenation can fall critically during intramedullary nailing of pathological femoral fractures

The intramedullary nailing of a femoral shaft metastatic fracture or an impending fracture has been complicated by hemodynamic accidents in up to 13% of patients. In previous studies, otherwise healthy patients pulled well through the nailing despite high pulmonary shunting and vascular tone and right ventricular strain. We hypothesized that unfavorable hemodynamic and oxygenation trends milder than catastrophic ones can be found intraoperatively in most patients with a pathological fracture and cancer-affected lungs.

Eleven patients with a femoral metastatic fracture or an impending fracture were studied in general anesthesia. Radial artery and fast-response pulmonary artery catheters were inserted. Pre-, intra-, and postoperatively, 26 variables were measured and/or calculated up to 20 hours. Reamed nailing with a gamma nail was performed.

At awake baseline, the mean pulmonary arterial pressure was 20 mm Hg ± 7 mm Hg and the shunt flow was 19% ± 6%. As response to the nailing, shunting increased from 14% ± 7% (mechanically ventilated) to 23% ± 10% (p < 0.05), and mean pulmonary arterial pressure increased to 29 mm Hg ± 6 mm Hg (p < 0.001). Oxygenation deteriorated to a level typical of acute lung injuries (Pao2/FIO2 242 mm Hg ± 73 mm Hg; p < 0.05). Intraoperatively, the oxygen delivery was poor, and acidosis developed (base excess, -2.9, p < 0.05).

The baseline condition of patients with a pathological femoral fracture was comparable with that of healthy patients subjected to femoral fracture surgery. After reaming, arterial oxygenation deteriorated, being clinically poor for the rest of the study. We suggest increased inspiratory oxygen concentration intra- and postoperatively and maintenance of oxygen delivery by transfusions as needed, especially because hypoxia stimulates the growth of cancer.