Effects of inhalation of different concentrations of carbon monoxide on brain death-induced lung injury in rats / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effects of inhalation of different concentrations of carbon monoxide (CO) on brain death (BD)-induced lung injury in rats. Methods Thirty-two pathogen free adult male Wistar rats weighing 250-300 g were randomly divided into 4 groups ( n= 8 each) group Ⅰ sham operation (group S);group Ⅱ brain death (group BD) and group Ⅲ and Ⅳ BD + CO 0.025% and 0.050% (group C1, C2 ). The animals were anesthetized and tracheally intubated. Fogarty catheter was inserted into the skull. BD was induced by inflating the balloon slowly at 20 μl/min until apnea developed. The animals were then mechanically ventilated (VT 10 ml/kg, RR 50 bpm, PEEP 2 cm H2O) with 40% O2 in N2 . In group Ⅲ and Ⅳ CO 0.025% and 0.050%were added to the air mixture respectively. In group S the balloon was not inflated. BD was confirmed by apnea,dilated pupils and flat EEG. In group BD,C1 and C2, MAP was maintained at 80-120 mm Hg by norepinephrine infusion. The arterial blood gas analysis was performed before (baseline) and immediately after BD was confirmed (T1) and at 30, 60, 90 and 120 min (T2-5) of CO inhalation. The animals were then sacrificed. The plasma concentrations of IL-6 and TNF-α and the activity of myeloperoxidase (MPO) in the lungs were measured. The W/D lung weight ratio and lung injury score (LIS) were recorded. Results BD significantly decreased PaO2/FiO2, BE and pH while increased plasma IL-6 and TNF-α concentrations, MPO activity in the lungs, the W/D ratio and lung injury score as compared with group S. CO inhalation ameliorated the deleterious effects induced by BD. The antiinfiammatory effect of 0.050% CO was better than that of 0.025 % CO. Conclusion Inhalation of 0.025 % or 0.050% CO can ameliorate BD-induced lung injury in rats, but there is no significant difference in the efficacy.