COAGULATORY RESPONSE AFTER FEMORAL INSTRUMENTATION AFTER SEVERE TRAUMA IN SHEEP

Objective: Pulmonary complications after intramedullary femoral nailin g have been attributed to bone marrow fat embolization and a variety o f cascade effects. We investigated whether the coagulatory response af ter intramedullary femoral nailing in merino sheep is altered after se vere trauma. Methods: Adult merino sheep were submitted to hemorrhagic shock (2 hours, 50 mm Hg) and unilateral lung contusion. After recove ry (day 3 of the study), reamed femoral intramedullary nailing (RFN), unreamed femoral intramedullary nailing (UFN), or plate osteosynthesis of the femur (P) was performed. Pulmonary artery pressure, central ve nous levels of factor V, protein C, antithrombin III, and fibrinogen, were determined. At 1 and 3 days before and after femur instrumentatio n, pulmonary capillary permeability was assessed on the basis of the c omparative albumin content in bronchoalveolar lavage fluid. Results: G roup RFN, n = 8; group UFN, n = 7; group P, n 6, A significant (p < 0. 05) postoperative increase in the relative albumin content in terms of the BAL/plasma albumin ratio was measured in group RFN (day 3 preoper atively: 0.38 +/- 0.05 day 3 postoperatively: 0.53 +/- 0.06, p < 0.05 (RFN vs. P), which contrasted with group UFN (day 3 preoperatively: 0. 44 +/- 0.09, day 3 postoperatively: 0.46 +/- 0.09, no significant diff erence). This evidence of increased pulmonary permeability occurred in association with evidence of increased activation of coagulation fact ors (data presented as percentage of day 3 preoperative baseline value s), The data for fibrinogen (15 min postoperatively) is as follows: gr oup RFN, 74 +/- 9% (p < 0.05 vs. P); group UFN, 83 +/- 8% (not signifi cant); group P, 98 +/- 6%, The data for antithrombin III (15 min. post operatively) is as follows: group RFN, 72 +/- 6% (p < 0.05 vs. P); gro up UFN, 79 +/- 8% (not significant); group P, 92 +/- 8% (not significa nt). Conclusion: After severe trauma, an increase of pulmonary permeab ility after reamed femoral nailing was associated with increased consu mption of coagulation factors. After unreamed nailing, a similar trend was apparent, but this was not found to be statistically significant. These data provide support for the theory that after severe trauma, u nreamed femoral nailing reduces but does not abolish pulmonary sequela e when compared with reamed femoral nailing.