PATHOPHYSIOLOGY OF OVINE SMOKE-INHALATION INJURY TREATED WITH EXTRACORPOREAL MEMBRANE-OXYGENATION

An ovine model was used to study the pathophysiology of smoke inhalati on injury treated with extracorporeal membrane oxygenation (ECMO). Smo ke inhalation is characterized by leukocyte-oxygen free-radical mediat ed acute lung injury. Treatment with ECMO was by extracorporeal venoar terial or venovenous perfusion using a venous drainage reservoir, roll er pump, heat exchanger, and membrane lung oxygenator capable of oxyge n delivery to and carbon dioxide removal from a patient. Blood-foreign surface interactions are known to occur during ECMO. We examined the effects of ECMO on circulating leukocytes, oxygen free-radical activit y, thromboxane release, and gas exchange after smoke inhalation injury . Animals treated with smoke and ECMO had significantly increased circ ulating thromboxane B2 levels and oxygen free-radical activity compare d with sham-treated animals and animals treated with smoke and mechani cal ventilation (MV). Likewise, there was a significant increase in lu ng wet-to-dry weight ratios in animals treated with smoke and ECMO com pared with those treated with smoke and MV. These data may account for the initial deterioration in native lung function after the initiatio n of ECMO and imply that ECMO may potentiate the pathophysiology of sm oke inhalation injury.