Preceding trauma lessens the degree of respiratory dysfunction in septicaemic pigs

Ten anaesthetised and mechanically ventilated pigs were subjected to musculoskeletal trauma two hours before induction of septicaemia with live Staphylococcus aureus, 10(11) colony forming units (trauma/sepsis group). The effects on haemodynamic and pulmonary function were compared over a period of 44 hours with those on 11 pigs that were identically treated except that they were not subjected to the trauma (sepsis alone group). The induction of sepsis produced similar transient pulmonary hypertension in both groups (mean (SD) in the trauma/sepsis group 48 (5) mmHg compared with 51 (6) mmHg in the sepsis group). In the trauma/sepsis group the decline in lung/thorax compliance was significantly less pronounced at 8 and 20 hours; the arterial oxygen tension was significantly better maintained at 32 and 44 hours; and the haemodynamics were better preserved, with significantly lower mean pulmonary arterial pressures at 20 and 44 hours than in the sepsis group. In conclusion, musculoskeletal trauma preceding septicaemia significantly lessened the degree of ensuing pulmonary dysfunction. This effect could be the results of reduced autoinjury by immunocompetent cells responding subnormally, but these mechanisms require further study.