新生儿呼吸支持中呼气末二氧化碳分压的监测意义

目的比较无创面罩、经鼻导管及有创机械通气三种方法监测的新生儿呼气末二氧化碳分压(end tidal carbon dioxide pressure,PetCO₂)及其与动脉血二氧化碳分压(arterial carbon dioxide pressure,PaCO₂)的相关性。方法选取2017年10月至2020年1月在我院新生儿科住院期间需呼吸支持治疗的患儿53例,分别监测患儿入院时、呼吸支持时及病情好转撤机后的PetCO₂,包括经鼻导管、无创面罩及有创通气时三种方式监测PetCO₂,并同时配对分析相应患儿动脉血血气分析中的PaCO₂。结果(1)无创面罩监测的PetCO₂低于PaCO₂(40.41±10.21)mmHg比(42.85±10.32)mmHg(1 mmHg=0.133 kPa),t=11.88,P<0.01],两者之间呈显著的正相关性(r=0.97,P<0.01);无创面罩监测的PetCO₂偏倚平均值是(1.20±2.31)mmHg,仅4.5%(5/110)在95%CI以外。(2)经鼻导管监测的PetCO₂也低于PaCO₂均值(40.93±10.55)mmHg比(42.01±10.50)mmHg,t=4.12,P<0.01],两者之间呈显著的正相关性(r=0.96,P<0.01);经鼻导管监测的PetCO₂偏倚平均值是(2.44±2.56)mmHg,仅4.6%(7/150)在95%CI以外。(3)气管插管机械通气患儿的PetCO₂同样低于PaCO₂(43.33±10.26)mmHg比(49.37±11.34)mmHg,t=13.83,P<0.01],两者之间同样呈显著的正相关性,相关性较无创通气患儿偏低(r=0.94,P<0.01);有创正压通气患儿的PetCO₂偏倚平均值是(0.90±0.82)mmHg,仅3.9%(2/51)在95%CI以外。(4)按胎龄分组,早期早产儿和晚期早产儿的PetCO₂分别为(37.25±11.32)mmHg和(39.58±10.37)mmHg,均低于足月儿PetCO₂(42.69±10.66)mmHg],三组患儿的PetCO₂与PaCO₂均呈正相关;早期早产儿的PetCO₂与PaCO₂相关性为三组中最低(r=0.89,P<0.01)。结论经鼻导管、无创面罩及有创通气时监测PetCO₂均与患儿的PaCO₂有较好的相关性和一致性,能较准确地反映患儿PaCO₂水平,其中无创通气患儿PetCO₂和PaCO₂的相关性优于有创通气患儿;晚期早产儿和足月儿的PetCO₂与PaCO₂相关性优于早期早产儿。

Monitoring significance of end-respiratory carbon dioxide partial pressure in neonatal respiratory support

Objective To compare the neonatal end tidal carbon dioxide pressure(PetCO₂)and its correlation with arterial carbon dioxide pressure(PaCO₂)monitored by non-invasive mask,accessory flow nasal catheter and invasive mechanical ventilation.Methods From October 2017 to January 2020,53 cases of newborn who were needed respiratory support treatment in our hospital were selected.PetCO₂was detected at admission,respiratory support and after weaning,including nasal catheter,non wound mask and invasive ventilation,and at the same time matching analysis of the corresponding with PaCO₂artery blood gas analysis.Results(1)PetCO₂monitored by mask was lower than PaCO₂(40.41±10.21)mmHg vs.(42.85±10.32)mmHg(1 mmHg=0.133 kPa),t=11.88,P<0.01],and there was a significant positive correlation between PetCO₂and PaCO₂(r=0.97,P<0.01);the mean bias of PetCO₂monitored by mask was(1.20±2.31)mmHg,only 4.5%(5/110)was outside the 95%confidence interval.(2)PetCO₂monitored by nasal catheter was also lower than the mean PaCO₂(40.93±10.55)mmHg vs.(42.01±10.50)mmHg,t=4.12,P<0.01],showing a significant positive correlation(r=0.96,P<0.01);the mean bias of PetCO₂monitored by nasal catheter was(2.44±2.56)mmHg,and only 4.6%(7/150)was beyond the 95%confidence interval.(3)PetCO₂of neonates with endotracheal intubation and mechanical ventilation was also lower than PaCO₂(43.33±10.26)mmHg vs.(49.37±11.34)mmHg,t=13.83,P<0.01],and there was also a significant positive correlation between the two groups,which was lower than that of neonates with non-invasive ventilation(r=0.94,P<0.01).The mean PetCO₂bias for neonates with invasive positive pressure ventilation was(0.90±0.82)mmHg,and only 3.9%(2/51)were outside the 95%confidence interval.(4)According to gestational age,the PetCO₂of early and late preterm infants was(37.25±11.32)mmHg and(39.58±10.37)mmHg,respectively,which were lower than that of full-term infants(42.69±10.66)mmHg],and there was a positive correlation between PetCO₂and PaCO₂in all three groups.The correlation between PetCO₂and PaCO₂in early preterm infants was the lowest among the three groups(r=0.89,P<0.01).Conclusion The monitoring of PetCO₂through nasal catheter,mask and invasive ventilation has a good correlation and consistency with the level of PaCO₂in neonates,which can accurately reflect the level of PaCO₂in neonates.The correlation between PetCO₂and PaCO₂in neonates with non-invasive ventilation is better than that in neonates with invasive ventilation.The correlation between PetCO₂and PaCO₂in late preterm infants and term infants is better than that in early preterm infants.