目的　探讨高频振荡通气 (HFOV)及联合硫酸镁 (Mg SO4 )治疗合并持续肺动脉高压(PPH)的重症胎粪吸入综合征 (MAS)模型氧合、循环功能 ,血镁浓度及肺组织病理改变。　方法　以2 0 %胎粪混悬液制备重症 MAS模型 ,健康新生猪随机分为 3组 ,即模型 HFOV治疗组 (HFOV组 ,n= 6 ) ,HFOV+Mg SO4 治疗组 (HFOV+Mg SO4 组 ,n=7) ,HFOV对照组 (对照组 ,n=5 ) ,HFOV+Mg SO4 组同时静脉持续泵入 Mg SO4 。监测生命体征、血气、血镁浓度。　结果　 (1) HFOV和 HFOV+Mg SO4 治疗均使 MAS模型动脉血氧分压 (Pa O2 )、动脉血氧 /肺泡血氧分压比 (a/ APO2 )增加 ,肺泡-动脉血氧分压差 (A- a DO2 )、肺内分流 (Qs/ Qt)降低 ,治疗 30 min与治疗前比差异有非常显著性 (P<0 .0 1)。HFOV组各时间点 Pa O2 、a/ APO2 低于对照组 ,A- a DO2 、Qs/ Qt高于对照组 (P<0 .0 5 )。HFOV+Mg SO4 组治疗 12 0 m in后上述指标与对照组差异无显著性 (P>0 .0 5 )。 (2 )尽管氧合功能改善 ,单独 HFOV对重症 MAS的 PPH无降低作用 ,联合 Mg SO4 治疗 30 min即可有效降低 PPH(P<0 .0 5 ) ,并保持疗效。(3) HFOV组较 HFOV+Mg SO4 组有明显肺出血 ,出血沿肺段、小叶分布 ,两组病理评分差异有显著性 (P<0 .0 5 )。 (4) HFOV+Mg SO4 组血镁浓度较治疗 Objective To investigate the effects of high frequency oscillatory ventilation (HFOV) and magnesium sulfate (MgSO4) on oxygenation, circulatory function, serum magnesium concentration and pathological changes of lung in the severe meconium aspiration syndrome (MAS) model with continuous pulmonary hypertension (PPH) . Methods Severe MAS model was established with 20% of meconium suspension. Healthy newborn pigs were randomly divided into three groups: model HFOV group (HFOV group, n = 6), HFOV + MgSO4 group (HFOV + Mg SO4 group , n = 7). HFOV control group (control group, n = 5) and HFOV + MgSO4 group were simultaneously pumped into MgSO 4 intravenously. Monitoring vital signs, blood gas, serum magnesium concentration. Results (1) Both HFOV and HFOV + MgSO4 treatment increased the values ​​of Pa O2, aO2 / aO2, (A-a DO2) and pulmonary shunt (Qs / Qt) decreased significantly after treatment for 30 min and before treatment (P <0.01). PaO2, a / APO2 in HFOV group were lower than those in control group at each time point, and A-a DO2 and Qs / Qt were higher than those in control group (P <0.05). There was no significant difference between HFOV + MgSO4 group and control group after 12 0 m in (P> 0.05). (2) Despite the improvement of oxygenation function, HFOV alone had no effect on the PPH of severe MAS. Combined with MgSO4 treatment for 30 min, the PPH was effectively reduced (P <0.05) and the effect was maintained. (3) There was significant pulmonary hemorrhage in HFOV group compared with HFOV + Mg SO4 group, the distribution of hemorrhage was along the pulmonary segment and the leaflet. There was significant difference between the two groups (P <0.05). (4) HFOV + Mg SO4 blood magnesium concentration than the treatment group