ABSTRACT

There is increasing evidence that oxygen derived free radicals are involved in the injury that occurs following the reperfusion of ischaemic tissue. Deferoxamine by preventing hydroxyl radical production and scavenging superoxide anion may attenuate this injury and its effects were evaluated following 4 hours of static hypothermic pulmonary preservation. Left lung autotransplantation was performed in 12 mongrel dogs. The autograft was initially flushed with 1000 cc of modified Collins solution and then stored in an inflated state for 4 hours in 4ºC saline. Six dogs received deferoxamine 500 mg intravenously infused before and immediately after the time of reperfusion. Following reimplantation, contralateral pulmonary artery ligation was performed and the animals were then maintained on a fixed FiO2 (40%) and monitored for 6 hours. During the first hour of reperfusion arterial pO2 was significantly better in the deferoxamine treated dogs (p < 0.05). Alveolar-arterial oxygen gradients were also lower (p < 0.05). Pulmonary vascular resistance was not different between groups. We conclude that deferoxamine improves gas exchange in the immediate reperfusion period and that further investigation of its use is warranted.

RESUMO

Há recentes evidências de que radicais livres derivados do oxigênio estáo envolvidos na lesão tecidual decorrente de isquemia e subseqüente reperfusão. A desferoxamina (DF), evitando a produção de radicais hidroxila e eliminando o ânion superóxido, pode atenuar este dano, sendo seus efeitos aqui avaliados após quatro horas de preservação pulmonar hipotérmica. O auto-transplante pulmonar esquerdo foi realizado em 12 cães mestiços. O pulmão foi, inicialmente, perfurado com 1000 ml de solução de Collins modificada e mantido insuflado, colocado sob refrigeração (4ºC) em solução salina durante quatro horas. Seis cães receberam 500 mg de DF administrados E.V. durante o período isquémico e imediatamente após iniciar a reperfusão. Após reimplante e ligadura da artéria pulmonar direita, os animais foram mantidos numa FiO2 fixa (49%) e monitorizados por quatro horas. Durante a primeira hora pós-reperfusão, o pO2 arterial foi sifnif¡cativamente superior no grupo tratado com DF (p < 0.05). O gradiente alvéolo-arterial foi também inferior (p < 0.05). A resistência vascular pulmonar foi semelhante em ambos os grupos. Concluímos que a desferoxamina permite melhor troca gasosa no período imediatamente após reperfusão e que sua investigação, na área da preservação pulmonar, deve ser estimulada.

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Article receive on Saturday, November 3, 1990