获取新生儿头罩给氧时供气流量与鼻腔局部环境二氧化碳(CO₂)浓度变化关系的数据，探讨新生儿合理使用头罩给氧的规律。

2005年9月至2005年11月，随机选取本院新生儿重症监护病房(NICU)排除肺部疾患的新生儿24例。按使用大、中、小三种型号头罩将其分为3组(各8例)，用空氧混合器固定供氧(O₂)浓度为21%，分别测定3组不同供气流量及无头罩对照条件下，新生儿鼻前庭内、外的CO₂浓度。

①头罩供气流量为0时，随着时间的增加，各型号组头罩内的CO₂浓度逐渐增加。②随着头罩供气流量增加，大、中、小各型号组头罩内新生儿鼻前庭内、外CO₂浓度都显著下降，均呈直线负相关关系(P＝0.000)。③大、中、小各型号组头罩内新生儿的鼻前庭内、外的CO₂浓度：在供气流量为0时，明显高于无头罩对照时相应的新生儿，差异有显著意义(P<0.01)；在供气流量为1 L/min或2 L/min时，与无头罩对照时相应新生儿比较，差异无显著意义(P>0.05)；在供气流量≥3 L/min时，均明显低于无头罩对照时相应的新生儿，差异有显著意义(P<0.01)。

只要供气流量≥1 L/min，便不会因为头罩给氧引起头罩内CO₂储留，且供气流量≥3 L/min时，尚有利于驱散头罩内CO₂。

To detect carbon dioxide(CO₂) concentration in nasal cavity of neonates with different sizes of head box supplied different flow rate.

To survey CO₂ concentration in neonatal nasal cavity of every 8 neonates in different sizes of head box at different flow rate of gas by the CES-10, the pigeon Ⅰ type and the blender of air-oxygen.

The statistics show that ① when the flow rate of gas in the head box was 0, CO₂ concentration increases gradually along with the time in different sizes of head box.② CO₂ concentration of each group was highly negative correlated with the flow rate of gas(P=0.000). ③ When the flow rate of gas in the head box was 0, CO₂ concentration of each group was higher than the groups which have not used the head box, there are significant differences(P<0.01). When the flow rate of gas in the head box was 1 L/min or 2 L/min, there are no significant differences between groups with and without the head box(P>0.05). When the flow rate of gas in the head box was above 3 L/min, CO₂ concentration of each group was lower than the group without the head box, there are significant differences(P<0.01).

When the flow rate of gas in the head box was above 1 L/min, CO₂ retention can not be retained in the head box. When the flow rate of gas in the head box was above 3 L/min, it make for dispersing CO₂ in head box.