呼气末正压通气对小儿麻醉诱导期无通气时限的影响及其与年龄和体重的相关性

Effect of positive end-expiratory pressure on duration of nonhypoxic apnea during induction of pediatric general anesthesia and its correlation with age and weight

目的探讨呼气末正压通气(PEEP)能否延长小儿全身麻醉诱导期无通气时限,及其与年龄、体重的相关性。方法 40例1～8岁,美国麻醉医师学会分级Ⅰ或Ⅱ级,拟在全身麻醉下行择期手术的患儿,随机分入PEEP组和对照组。静脉注射丙泊酚、芬太尼和罗库溴铵行麻醉诱导,小儿自主呼吸减弱后面罩给氧并给予压力控制模式(PSV)机械辅助通气,设定吸气压力15cmH2O(1cmH2O=0.098kPa),根据患儿年龄调整呼吸频率,其中PEEP组在对照组的基础上加用6cmH2O的PEEP。两组患儿的机械通气时间均为3min。记录机械辅助通气停止至脉搏血氧饱和度(Sp O2)降至99%(t99)、95%(t95)和90%的时间(t90),采用线性回归分析两组小儿无通气时限(即t90)与年龄及体重的相关性。结果两组间t99、t95和t90的差异均无统计学意义(P值均>0.05),对照组患儿的年龄、体重与无通气时限的线性拟合良好,R2值分别为0.895和0.878;PEEP组患儿相应的拟合度降低,R2值分别为0.604和0.412。PEEP组的年龄、体重与无通气时限的相关系数分别为0.771、0.642,均显著低于对照组的0.946、0.937(P值均<0.05)。结论 PEEP不能显著延长1～8岁小儿全身麻醉诱导期无通气时限,但可以减少年龄和体重对无通气时限的影响。

Objective To investigate whether positive end-expiratory airway pressure （PEEP） during anesthesia induction increases duration of nonhypoxic apnea and its correlation with age and weight in pediatric patients. Methods Forty children, aged 1 to 8 years old, American Society of Anesthesiologists （ASA） grade I - Ⅱ , were scheduled for elective surgery and randomly divided into PEEP group and control group. General anesthesia was induced with propofol, fentanil and rocuronium. After spontaneously breathing weakened, assisted mechanical ventilation was performed under pressure controlled pattern for 3 min until tracheal intubation. The inspiratory pressure was 15 cmHzO （1 cmH20 = 0. 098 kPa）. PEEP （6 cmH20） was applied in the PEEP group additionally. Apnea duration was recorded when saturation of blood oxygen （SpO2） reached 99% （t99）, 95% （ t95 ） and 90 % （ t90 ）. The correlation between the nonhypoxic apnea duration （ t90 ）, age and weight was analyzed by linear regression. Results There was no significant difference in t99, t95 and t90 between the two groups （all P〉0.05）. The result of linear regression showed that in the control group R2 values of nonhypoxia apnea duration with children＇s age and weight were 0. 895 and 0. 878, respectively, while they were 0. 604 and 0. 412 in the PEEP group. The coefficients of correlation of age and weight with nonhypoxia apnea duration in the PEEP group were 0.771 and 0.642, respectively, which were significantly lower than those in the control group （0. 946 and 0.937, both P〈0.05）. Conclusion PEEP during induction of general anesthesia will not increase nonhypoxic apnea duration in children of 1 to 8 years old. However, it can reduce the effect of age and weight on nonhypoxic apnea duration. （Shanghai Med J, 2013, 36.. 683-686）