新生儿首次呼吸前后脐带动静脉血液氧和二氧化碳变化探索呼吸调控机制的初步报告II—同一个新生儿同一时间的脐带动静脉血液氧和二氧化碳分压差值个体化分析*

目的: 为探讨新生儿自主呼吸产生机制,前文已对新生儿出生后自主呼吸开始前脐带动静脉氧气和二氧化碳差值进行了人群组间分析;而本部分则对相关信息进行个体化分析。方法: 在产前经所有胎儿父母签署知情同意书,新生儿出生后还没有呼吸之前在脐带动脉和脐带静脉分别连续逐搏取血,仅有3例同时采集到Pua和Puv血液样本进行血气分析测定,计算分析脐带静脉和脐带动脉的异同和动态变化。结果: 虽然准备了数十产妇,但仅有3例同时采集到Pua和Puv血液样本,同一时间的PuvO₂显著高于PuaO₂（P均<0.01）,平均相差（24.17±7.09） mmHg;而PuvCO₂显著低于PuaCO₂（P均<0.01）,平均相差（-7.67±3.70） mmHg。在同一时间的Puv-uaO₂显著高于Puv-uaCO₂（P<0.05）。结论: 新生儿出生后自主呼吸前,全部氧气供应由脐带静脉运输,只要胎盘开始剥离则新生儿的PuaO₂随时间（心跳次数）逐渐降低,当PuaO₂达到触发呼吸阈值（最低值）诱发第一次吸气开始其自主呼吸。

Preliminary report on partial pressure changes of oxygen and carbon dioxide in umbilical artery and vein before and after the first breath in Chinese neonates II—The personalized analysis of partial pressure of oxygen and carbon dioxide difference between umbilical artery and vein at same time in same newborn

Objective: In order to explore the mechanism of neonatal spontaneous breathing, the difference of oxygen and carbon dioxide between umbilical cord arteries and veins before the start of spontaneous breathing after birth has been analyzed among people. In this part, the related information is analyzed individually. Methods: After all fetal parents signed the informed consent before birth, and before the newborn was born and did not breathe, the umbilical cord was exposed as quickly as possible, and the heparinized arterial indwelling needle was inserted into the umbilical artery and umbilical vein in the direction of newborn and placenta, and then blood was taken continuously. Although dozens of mothers were selected,but only 3 cases were collected from Pua and Puv blood samplers at the same time for blood gas analysis and determination, and the differences and dynamic changes of umbilical vein and umbilical artery were calculated and analyzed. Results: In all 3 none spontaneous breathing newborns,PuvO₂ was significantly higher than PuaO₂ at the same time (P<0.01), with an average difference of (24.17±7.09) mmHg; while PuvCO₂ was significantly lower than PuaCO₂ (all P<0.01), with an average difference of (-7.67±3.70) mmHg.The difference of Puv-uaO₂ was significantly higher than those of Puv-uaCO₂ (P<0.05). Conclusion: PuaO₂ decreases gradually with time (heartbeat frequency) before spontaneous breathing after the delivered fetus as a newborn, and it induces the first inhalation to start spontaneous breathing when it reaches the threshold of triggering breathing.