EFFECTS ON PULMONARY PHYSIOLOGY OF REAMED FEMORAL INTRAMEDULLARY NAILING IN AN OPEN-CHEST SHEEP MODEL

We have recently developed an open-chest sheep model to monitor and st udy the effects of major orthopedic procedures on pulmonary physiology . In this pilot study, we focused on reamed intramedullary femoral nai ling in animals without pulmonary injury. Details of the model are des cribed herein. The control group consisted of sheep that underwent tho racotomy and invasive monitoring only, while the study group also unde rwent femoral osteotomy, reaming, and intramedullary nailing. Baseline , postthoracotomy, and postreaming/nailing values were recorded for me an pulmonary arterial pressure, central venous pressure, left arterial pressure, dynamic compliance, arterial blood gas, mixed venous O-2, c ardiac index, and mean arterial pressure so that hemodynamic and oxyge n transport data could be calculated, Postprocedure values were record ed at hourly intervals for 4 h. A physiologically stable, reproducible model was created. No statistically significant differences were foun d between the control and experimental groups, indicating no adverse e ffect of femoral reaming/nailing. In one animal, using echocardiograph y, pulmonary embolization was documented while reaming and inserting t he intramedullary nail. Reamed femoral intramedullary nailing is not d etrimental to sheep with otherwise normal lungs. This finding suggests that femoral reaming and nailing in trauma patients without associate d pulmonary injuries and otherwise normal lungs may be carried out wit hout risk of inducing significant respiratory complications.