[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.