
Background: Muscle compartment syndrome is a known morbid complication of physiologic and mechanical lower extremity trauma. Determining the critical range in different centers for optimal management is suggested. Methods: In a two sectional prospective clinical study, 149 referral patients of lower extremity trauma and vascular injuries were recruited for compartment pressure assessment during eleven months by Whiteside apparatus. Compartment pressures and ΔP simultaneously recorded in admission, pre and post operative and before fasciotomy and discharge in order to determine critical range, the outcome and comparing for correlations. Results: Of 149 patients, 117 cases of normal recovery, 14 cases of activity deficits, 14 fasciotomized patients and four amputations were detected. Causes were 122 trauma cases and 27 thrombo-embolic events. Pressure range was 12- 46 mmHg and ΔP was ranged 58-25. There were significant correlations between extremity outcomes and compartment pressure in all defined periods (P=<0.02). ΔP was not correlated except in post operation time (P=<0.001). Significant correlation was found between outcome and fluid resuscitations (P=<0.001). Fasciotomized patients were presented significant correlations with liquid resuscitation, operative duration, compartment pressures and ΔP at defined periods (P=<0.001). Critical thresholds were found similar to medical literature, compartment pressure about 35- 40 mmHg and ΔP lower than 20 mmHg below diastolic pressure. Conclusion: regarding the results, we conclude that frequent simultaneous compartment pressure and ΔP recording alongside clinical examination is necessary. Even without clinical presentation, fasciotomy is advocated in critical levels. On-time fasciotomy may be final therapeutic key but do not completely support the outcome.