新生儿机械通气时呼气末二氧化碳分压与动脉血二氧化碳分压相关性分析

Correlation between end-tidal carbon dioxide and partial pressure of arterial carbon dioxide in ventilated newborns

摘要:

目的 探讨新生儿机械通气时呼气末二氧化碳分压（PetCO₂）和动脉血二氧化碳分压（PaCO₂）的相关性。方法 对31例气管插管机械通气的新生儿进行持续主流PetCO₂监测，并同时配对检测85例次动脉血血气分析，评估PetCO₂与PaCO₂的相关性和一致性。结果 31例机械通气新生儿PetCO₂均值（41±10 mm Hg）低于PaCO₂均值（46±11 mm Hg）（P<0.01），二者具有显著正相关性（r=0.92，P<0.01）；平均偏倚是5.1±4.3 mm Hg，在95%一致性范围是（-3.3，13.6 mm Hg），5%（4/85）的数值在95%的可信区间以外。在氧合指数（OI）<300 mm Hg（n=48）时，PetCO₂和PaCO₂具有显著正相关性（r=0.85，P<0.01），平均偏倚是5.9±4.3 mm Hg，在95% 一致性范围是（-2.6，14.5 mm Hg），4%（2/48）的数值在95%的可信区间以外。OI≥300 mm Hg（n=37）时，PetCO₂和PaCO₂也有显著正相关性（r=0.91，P<0.01），平均偏倚是4.1±4.1 mm Hg，在95%一致性范围是（-3.9，12.1 mm Hg），仅5%（2/37）的数值在95%的可信区间以外。结论 在机械通气的新生儿中，PetCO₂和PaCO₂有较好的相关性和一致性。

Abstract:

To study the correlation between end-tidal carbon dioxide (PetCO₂) and partial pressure of arterial carbon dioxide (PaCO₂) in ventilated newborns. Methods Thirty-one ventilated newborn underwent mainstream PetCO₂ monitoring; meanwhile, arterial blood gas analysis was performed. The correlation and consistency between PetCO₂ and PaCO₂ were assessed. Results A total of 85 end-tidal and arterial CO₂ pairs were obtained from 31 ventilated newborns. The mean PetCO₂ (41±10 mm Hg) was significantly lower than the corresponding mean PaCO₂ (46±11 mm Hg) (P<0.01). There was a significant positive correlation between PetCO₂ and PaCO₂ (r=0.92, P<0.01). The overall PetCO₂ bias was 5.1±4.3 mm Hg (95% limits of consistency, -3.3 to 13.6 mmHg), and 5% (4/85) of the points were beyond the 95%CI. When the oxygenation index (OI) was less than 300 mm Hg (n=48), there was a significant positive correlation between PetCO₂ and PaCO₂ (r=0.85, P<0.01); the PetCO₂ bias was 5.9±4.3 mm Hg (95% limits of consistency, -2.6 to 14.5 mm Hg), and 4.2% (2/48) of the points were beyond the 95%CI. When the OI was more than 300 mm Hg (n=37), there was also a significant positive correlation between PetCO₂ and PaCO₂ (r=0.91, P<0.01); the PetCO₂ bias was 4.1±4.1 mm Hg (95% limits of consistency, -3.9 to 12.1 mm Hg), and 5% (2/37) of the points were beyond the 95%CI. Conclusions There is a good correlation and consistency between PetCO₂ and PaCO₂ in ventilated newborns.