[Does lung contusion and general injury severity have an effect on the lung following intramedullary femoral nailing? An animal model].

We evaluated changes in lung function after closed intramedullary femoral nailing (IMN) in sheep. The effects of isolated IMN were compared with those of nailing after lung contusion and hemorrhagic shock. In adult female merino sheep a chronic lung lymph fistula was prepared according to the method described by Staub. At day 1, group 1 received right-sided lung contusion and hemorrhagic shock to a mean blood pressure of 50 mmHg for 2 h. Group 2 was the control group. At day 3 both groups were submitted to IMN, followed by a 2-h observation period. IMN caused a transient significant increase in pulmonary artery pressure and central venous triglycerides in both groups. Chemiluminescence of isolated polymorphonuclear leukocytes (PMNL) decreased in group 1 from 2.699 +/- 0.344 to 2.460 +/- 0.187 x 10(6) cpm/25000 PMNL and increased in group 2 from 2.757 +/- 0.127 to 3.824 +/- 0.439 x 10(6) cpm/25000 PMNL. Lymph flow in group 1 increased 1.5-fold while microvascular pressure decreased. In group 2 lymph flow increased less, while MVP increased. The filtration coefficient in group 1 was 5 times (7.533 +/- 0.044) that in the control group (1.45 +/- 0.133). Calculations of permeability indicated a 2-fold increase (0.044 group 1 vs 0.026 group 2). In the presence of previous lung contusion and hemorrhagic shock there is definite lung damage from IMN. This is probably mediated by stimulation of PMNL.