Use of tissue ultrafiltration for treatment of compartment syndrome: A pilot study using porcine hindlimbs

Objectives: To demonstrate the efficacy of compartment syndrome ultrafiltration for the treatment of acute compartment syndrome in an animal model. Our hypothesis is the removal of interstitial fluid will result in a reduction of intramuscular pressure compared with untreated controls in a model of bilateral induced compartment syndrome. Design: Controlled experimental model. Setting: Animal research facility. Patients/Participants: Three pairs of porcine hindlimbs. Intervention: Acute compartment syndrome was created in the pig hindlimb by infusion of saline to maintain the intramuscular pressure 30 mm Hg greater than the animal's mean arterial pressure for 8 hours. After a 2-hour reperfusion interval, ultrafiltration (removal of fluid through 1 mm diameter porous catheters, connected to -500 mm Hg suction) was commenced in 1 limb only and continued for 9.5 hours. Main outcome measures: Intramuscular pressure, ultrafiltrate volume, ultrafiltrate and serum levels of creatine kinase and lactate dehydrogenase, histologic measurement of extracellular and intracellular edema, as well as the degree of cellular necrosis. Results: Intramuscular pressure tended to be lower on the treated side at the end of the treatment period [treated leg: 9.3 ± 4.0 mm Hg (± SE), control leg: 19.3 ± 1.4 mm Hg, P = 0.03]. Analysis of ultrafiltrate fluid showed that levels of creatine kinase and lactate dehydrogenase were elevated compared with serum levels. Creatine kinase levels in serum were measured at 4150 ± 780 U/L, whereas ultrafiltrate levels of creatine kinase were 28,700 ± 17,700 U/L (± SE) (P = 0.1). Lactate dehydrogenase was measured at 1950 ± 180 U/L in serum, but markedly elevated in ultrafiltrate [160,000 ± 88,900 U/L (± SE), P = 0.05]. Quantification of cellular and interstitial dimensions showed no difference in control and experimental limbs. Quantification of the degree of muscle necrosis revealed 6.1 ± 2.7% necrosis in the treated limb compared to 11.3 ± 1.6% necrosis in the control group (P = 0.02, df = 2, 1-tailed paired t test). Conclusion: This pilot study demonstrates the feasibility of tissue ultrafiltration for reduction of intramuscular pressure in this porcine model. Further studies are underway. Compartment syndrome ultrafiltration may be useful prophylactically in patients at risk for acute compartment syndrome. Sampling of interstitial fluid and frequent measurement of intramuscular pressure may allow earlier diagnosis and treatment of acute compartment syndrome, whereas the reduction of tissue pressure by compartment syndrome ultrafiltration may prevent acute compartment syndrome from occurring. Additionally, compartment syndrome ultrafiltration will not hinder the ability of clinicians to use the clinical examination and pressure monitoring as the gold standard.