肺复张联合小潮气量机械通气对海水淹溺致急性肺损伤兔氧合的影响

目的 研究肺复张与小潮气量机械通气联合应用对海水淹溺致急性肺损伤兔的氧合和呼吸力学的影响及安全性评价.方法 18只新西兰兔气管内缓慢灌入2 ml/kg海水,复制成海水淹溺致急性肺损伤兔模型,随后给予6 ml/kg小潮气量机械通气3 h.按是否给予肺复张分为对照组和肺复张组(RM组),每组9只.对照组小潮气量机械通气结束后即行肺高分辨率CT检查.RM组小潮气量通气结束后即给予肺复张,方法为:持续气道正压(CPAP),压力2.94 kPa,时间20 s,小潮气量机械通气期间观察记录2组氧合、呼吸力学、循环、血清炎性因子的变化.结果 RM组PaO2在各观察点明显改善,与对照组比较差异有统计学意义(P<0.05);能维持2 h,RM组在复张后15 min和30 min PaC02高于对照组,差异有统计学意义(P<0.05);平台压(Pplat)降低、静态顺应性(Crs,stat)增加,与对照组比较差异有统计学意义(P<0.05);RM组15 min平均动脉压下降(P<0.05),1 h后基本恢复基础水平;复张过程中,心率增加、血压下降,30～90 s恢复,在15 min时RM组心率较对照组低(P<0.05);2组血清肿瘤坏死因子α(TNF-α)、白介素-6(IL-6)差异无统计学意义(P>0.05);RM组肺高分辨率CT浸润影吸收好于对照组,无气压伤.结论 肺复张与小潮气量通气联合应用能够明显改善兔氧合和肺顺应性,减轻肺损伤,是一种安全有效的治疗海水淹溺致急性肺损伤的机械通气手段.

Effects of lung recruitment and lower tidal ventilation on gas exchange in rabbits with acute lung injury induced by seawater drowning

Objective To observe the therapeutic effect and safety of lung recruitment combined with lower tidal ventilation on acute lung injury induced by seawater drowning in rabbits. Methods Eighteen New Zealand rabbits were used for the experiment. Acute lung injury model was developed with intractracheal instillation of seawater (2 ml/kg). Then, the animals had been lower tidal ventilation (6 ml/kg) for three hours. The animals with lung recruitment maneuvers were designated as the experimental group (or the RM group), while those without lung recruitment were designated as the control group. For the RM group,continuous positive airway pressure (CPAP) was applied at a pressure of 2.94 kPa for 20 seconds. Then,arterial blood gas analysis, pulmodynamics, and hemodynamic status were made at various time points. Tumor necrosis factor (TNF-α) and interleukin-6 (IL-6) extracted from serum were also measured following treatment. Pulmonary high - resolution chromatography (HRCT) was also made after three hours of ventilation.Results For the RM group, the partial pressure of arterial oxygen (PaO2) at various time points increased significantly after lung recruitment within two hours(P < 0.05). When a comparison was made between the two groups, PaCO2 for the RM group was higher than that of the control group following lung recruitment at 15 min and 30 min respectively with statistical significance (P < 0.05). Airway plateau pressure (Pplat) decreased markedly(P <0.05)and static compliance increased with statistical significance (P < 0.05). Mean arterial pressure for the RM group decreased in 15 min (P < 0. 05), but almost restored to basic level within 1 h.During recruitment, mean arterial pressure decreased and heart rate increased, but came to normal levels after 30- 90 s. Heart rate at 15 min for the RM group was lower than that of the control group (P < 0.05). However,for both groups, no significant differences could be noted in TN F-α and IL-6 (P > 0.05). Conclusions Lung recruitment combined with lower tidal ventilation could significantly improve gas exchange and lung compliance,and alleviate lung injury, which might be a safe and effective method for the treatment of animals with acute lung injury induced by seawater drowning.