Ropivacaine-based Regional Anesthesia Exerts Muscle-protective Effects Despite Elevated Compartment Pressure in a Porcine Model of Acute Compartment Syndrome.

Abstract

BACKGROUND: Acute compartment syndrome (ACS) is a devastating sequela of orthopedic trauma characterized by elevated compartment pressure that precipitates tissue ischemia. The role of regional anesthesia in modulating these pathophysiological events remains controversial. This study investigated the impact of regional anesthesia via ropivacaine 0.2% (RPVC) on compartment pressure, systemic hemodynamics, biochemical markers, and tissue integrity in a porcine model of ACS. METHODS: Twenty male pigs underwent ACS induction in the tibialis anterior compartment by targeted inflation of an angioplasty catheter and were randomized to receive either RPVC or placebo via a regional catheter. Continuous compartment pressure and mean arterial pressure were recorded. Plasma samples and interstitial fluid were collected at predefined time points (T1, T3, T6, T8, and T10) to quantify creatine kinase, lactate, lactate dehydrogenase, and glucose. Histopathologic evaluation was performed at the end of the experiment (T10). RESULTS: At T10, compartment pressure was significantly elevated in the RPVC group (57.0 mmHg [49.0 to 59.0]) compared to placebo (41.5 mmHg [38.2 to 47.2]; P = 0.022), whereas mean arterial pressure remained comparable (RPVC: 63.0 mmHg [58.0 to 65.0] vs . placebo: 59.0 mmHg [56.2 to 61.8]; P = 0.13). Plasma biomarkers did not differ significantly ( e.g. , plasma creatinine kinase: RPVC 1940 U/l [868 to 3,334] vs . placebo 1,171 U/l [1,020 to 1,467]; P = 0.24). In contrast, interstitial analysis demonstrated a marked reduction in tissue injury markers in the RPVC group, with interstitial fluid lactate dehydrogenase significantly lower [24,475 U/l (19,500 to 28,213) vs . 113,800 U/l (91,000 to 116,600); P = 0.017] and interstitial fluid glucose substantially decreased (19.5 mg/dl [11.5 to 27.5] vs . 51.0 mg/dl [43.0 to 103.0]; P = 0.0043). RPVC-treated tissue exhibited attenuated degeneration and reduced necrosis in a blinded histopathologic scoring. CONCLUSIONS: Despite a higher compartment pressure, RPVC-based regional anesthesia yielded an improved regional metabolic profile and mitigated tissue injury in ACS. These findings suggest a protective effect in the observed timeframe that merits further clinical exploration.