Efeitos de subdoses de halotano e óxido nitroso em ratos / Effects of subdoses of halothane and nitrous oxide in rats

RESUMO

Background and Objectives - Chronic inhalation of anesthetic agents, due to their residual and additive effects, can produce deleterious changes in different organs and systems. The purpose of this experimental study was to evaluate some organic alterations in animals exposed to the chronic inhalation of halothane and nitrous oxide. Methods - The effects of subdoses of inhalational anesthetics were evaluated in 80 rats, 40 male and 40 female, allocated into 4 groups of 20 animals. Group 1 animals breathing room air; Group 2 halothane 50 ppm; Group 3 nitrous oxide 400 ppm; Group 4 halothane 50 ppm and nitrous oxide 400 ppm. The animals were exposed to the experimental conditions 6 hours per day, for 180 days. The following parameters were observed blood cells (segmented leukocytes, lymphocytes, eosinophils, monocytes); electrolytes (sodium, potassium, calcium); glutamic-oxalacetic and glutamic-piruvic transaminases, prolactine, stradiol, creatinine and glycemia; weight gain; histopathologic changes in differents organs (brain, heart, liver, kidney, testicle, aorta, stomach, bone marrow). Results - The histopathologic study showed normal organs in all groups. Stradiol and prolactine levels were bellow the limit of detection of the method. Transaminase were significantly reduced. In Groups 2 and 3 there was reduction in the levels of sodium, calcium, glucose, creatinine and of weight gain; in Group 3 the percentage of eosinophils were also reduced. In Group 4, the reduction i the same parameters were greater, with the additional reduction of potassium levels and segmented leukocytes; the percentage of pymphocytes and eosinophils increased and the monocytes remained unchanged. Conclusions - Under the experimental conditions, the simultaneous chronic inhalation of halothane and nitrous oxide induced greater changes as compared to the inhalation of each individual agent. Despiste alterations in biochemical data, blood cells and weight gain, no histopathological abnormality was observed