Lung protection after severe thermal burns with adenosine, lidocaine, and magnesium (ALM) resuscitation and importance of shams in a rat model.

The management of severe burns remains a complex challenge. Adenosine, lidocaine and magnesium (ALM) resuscitation therapy has been shown to protect against hemorrhagic shock and traumatic injury. The aim of the present study was to investigate the early protective effects of small-volume ALM fluid resuscitation in a rat model of 30% total body surface area (TBSA) thermal injury. Male Sprague-Dawley rats (320-340g; n=25) were randomly assigned to: 1) Sham (surgical instrumentation and saline infusion, without burn, n=5), 2) Saline resuscitation group (n=10), or 3) ALM resuscitation group (n=10). Treatments were initiated 15-min after burn trauma, including 0.7ml/kg 3% NaCl±ALM bolus and 0.25-0.5ml/kg/h 0.9% NaCl±ALM drip, with animals monitored to 8.25-hr post-burn. Hemodynamics, cardiac function, blood chemistry, hematology, endothelial injury markers and histopathology were assessed. Survival was 100% for Shams and 90% for both ALM and Saline groups. Shams underwent significant physiological, immune and hematological changes over time as a result of surgical traums. ALM significantly reduced malondialdehyde levels in the lungs compared to Saline (p=0.023), and showed minimal alveolar destruction and inflammatory cell infiltration (p<0.001). ALM also improved cardiac function and oxygen delivery (21%, p=0.418 vs Saline), reduced gut injury (p<0.001 vs Saline), and increased plasma adiponectin (p<0.001 vs baseline). Circulating levels of the acute phase protein alpha 1-acid glycoprotein (AGP) increased 1.6-times (p<0.001), which may have impacted ALM's therapeutic efficacy. We conclude that small-volume ALM therapy significantly reduced lung oxidative stress and preserved alveolar integrity following severe burn trauma. Further studies are required to assess higher ALM doses with longer monitoring periods.