高频振荡通气及联合硫酸镁治疗新生猪重症胎粪吸入综合征的实验研究

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

Treatment of Severe Meconium Aspiration Syndrome of Newborn Piglet by High Frequency Oscillatory Ventilation and Magnesium Sulphate

Objective To evaluate the effect of high frequency oscillation ventilation (HFOV) and HFOV+ MgSO 4 on oxygenation, pulmonary and systemic arterial pressure, histologic alterations, and serum magnesium concentration in severe meconium aspiration syndrome(MAS) piglets with persistent pulmonary hypertension(PPH). Methods Newborn piglets were randomized to HFOV group( n =6), HFOV+MgSO 4 group( n =7) and control group( n =5). Piglets of HFOV group and HFOV+MgSO 4 group received an intratracheal a 20% suspension of human meconium. All piglets were given HFOV, Piglet of HFOV+MgSO 4 group was given MgSO 4 intravenously simultaneously. Cardiopulmonary functions, blood gases were monitored and serum magnesium concentration of piglets in HFOV+MgSO 4 group were measured by atomic absorption spectrophotometric assay. Results (1) HFOV and HFOV+ MgSO 4 treatment showed improved oxygenation in MAS model, PaO 2,a/APO 2 increased significantly and A-aDO 2?,Qs/Qt decreased significantly in HFOV group at 30 minute ( P <0.01). Oxygenation was improved similarly in HFOV+MgSO 4 group. There were differences in oxygenation between HFOV group and Control group at all time ( P < 0.05). However, there were no difference in oxygenation between HFOV+MgSO 4 group and Control group after 120 min of treatment. (2) HFOV had no effect on PPH in HFOV group , while HFOV+MgSO 4 decreased pulmonary pressures at 30 min ( P <0.05) and persisted to the end. (3) More extensive pulmonary hemorrhage was found in HFOV group than that in HFOV+MgSO 4 group, the bleeding areas were distributed along with lung segments and lobules. (4) Serum magnesium concentration increased 2.3 fold in HFOV+MgSO 4 group, but the systemic arterial pressure was normal. Conclusions HFOV improved oxygenation of newborn piglets with severe MAS rapidly, but had no effect on PPH. PPH was supposed to be related to the pulmonary hemorrhage. HFOV + MgSO 4 resulted in an improvement in oxygenation, a significant decreased pulmonary pressure and alleviated pulmonary hemorrhage. MgSO 4 increased serum magnesium concentration significantly, but did not influence the systemic arterial pressure.