单侧膈神经切断对幼猪呼吸系统影响的实验研究

目的比较单侧膈神经切断对不同年龄幼猪肺功能及肺组织形态影响的差异，为临床上确定小儿行膈神经移位术的安全年龄范围提供理论及实验依据。方法健康雄性幼猪36只，按手术时日龄（10d、30d、50d）分为3组，每组12只，实验组6只，对照组6只。实验组于颈部将左侧膈神经切断，对照组仅行左侧膈神经暴露。分别于术前、术后30min及生长至3月龄时检测动脉血气、肺功能及进行胸透，并于3月龄时观察肺组织学改变。结果单侧膈神经切断后30min，10d及30d实验组分钟通气量（MV）和吸入潮气量（VTins）较术前下降（P〈0．05），50d实验组分钟通气量及吸入潮气量较术前无明显改变（P〉0．05）；3月龄时，各实验组与对照组比较分钟通气量和吸入潮气量均无显著差异（P〉0．05），但10d及30d实验组动态顺应性（Cdyn）下降（P〈0．05），气道阻力（Raw）增高（P〈0．05），50d实验组动态顺应性、气道阻力与对照组比较无明显差异（P〉0．05）。3月龄时实验组与对照组肺组织学比较，10d实验组左肺及右肺下半区肺泡直径（Da）减小，肺泡隔密度（Ds）增加（P〈0．05），30d实验组仅左肺下半区肺泡直径减小、肺泡隔密度增加（P〈0．05），而50d实验组双肺各区肺泡直径及肺泡隔密度与对照组比较均无显著差异（P〉0．05）。结论单侧膈神经切断将影响术时年龄较小幼猪的肺功能及肺组织形态，手术年龄越小影响越显著，而术时年龄较大幼猪膈神经切断对呼吸系统影响不明显。

Impact of unilateral phrenectomy on the respiratory system in piglets

Objective To investigate the differences in the impact on the respiratory system following unilateral phrenectomy in piglets of different ages. Methods 36 piglets were divided into three groups according to their ages at the operation (10 days, 30 days, and 50 days respectively). In each group six piglets underwent left cervical phrenectomy and the other six were sham-operated controls. Pulmonary functions and artery blood gas analysis were performed preoperatively , 30 minutes postoperatively, and at 3 months of age. Pulmonary histology at the age of 3 months old was also done. Results 30 minutes after unilateral phrenectomy, minute ventilation (MV) and inspiratory vital capacity (VTins) decreased in groups of 10 days old and 30 days old. No obvious change was noticed, however, 50 days old piglets.Compared to the control groups, dynamic compliance (Cdyn) decreased and airway resistance (Raw) increased postoperatively in the piglets operated on 10 days and 30 days at the age of 3 months old. Again, no statistically significant difference was observed between the 50 days old group and the control group. Density of alveolar septum (Ds) increased and diameter of alveolus (Da) decreased noticeably in piglets who underwent cervical phrenectomy at 10 days and 30 days of age. However there was no obvious change in the group operated at 50 days of age. Conclusions Unilateral phrenectomy in piglets of younger than 30 days old may cause abnormity of the pulmonary function and respiratory system. The younger the piglet, the more serious the consequences of the operation. Piglets older than 50 days tolerate the operation better and may not have respiratory dysfunction in the long run.