Acute compartment syndrome. Results of a clinical investigation of pressure and time thresholds for emergency fasciotomy

Background: Acute compartment syndrome of the leg is to be regarded as a tr aumatological emergency. Most specialists already agree that only a timely operative decompression of the afflicted compartment can prevent serious ti ssue damage. What still remains subject to discussion, however, is the prec ise tissue pressure above which the operation becomes imperative. Experimen tal human studies focusing on tissue pressure and muscle oxygenation have n ot yet been carried out. It was thus the aim of the present study to analyz e oxygen partial pressure of the anterior tibial muscle and peroneal action potential in a model compartment syndrome in man. Methods: In 22 healthy, normotensive volunteers, constant pressure values f rom 0 to 100 mmHg were induced in the anterior tibial muscle with antishock trousers. Over a period of up to 6 h measurements were made of (1) tissue pressure, (2) intramuscular oxygen partial pressure (pO(2)), and (3) muscle response potential (MRP) of the n. peroneus profundus by electroneurograph y. Results: We achieved a 97.7% (Q(25%)/Q(75%): 89.2/99.8) transfer of the pne umatic pressure to the lower leg. Already at intramuscular tissue pressures of 30-40 mmHg, hypoxia and reduction of MRP appeared. A reduction of the M RP to zero and pO(2) <1 mmHg was observed from a pressure of 50 mmHg. Tissu e pressure values of over 75 mmHg resulted almost without exception in anox ia of the muscle. Conclusions: Even under normal perfusion conditions, already slight increas es in pressure of above 30 mmHg lead to reduced tissue oxygenation and neur al function. We have to consider that with additionally traumatized muscle the ischemic tolerance is markedly reduced and due to unknown influences su ch as local vasoreactivity and capacity of autoregulation the nutritive per fusion cannot be determined. In the case of a severely injured muscle,to be on the safe side decompressive fasciotomy should therefore be carried out if pressure values remain above 30 mmHg.