热线风速仪监测小儿七氟烷麻醉诱导期呼吸力学的变化

Monitoring the changes of respiratory mechanics for Sevoflurane anesthesia induction with anemometer in children

目的本研究通过使用热线风速仪观察小儿七氟烷吸入麻醉诱导不同时期上呼吸道呼吸力学的变化,以期将七氟烷对呼吸的抑制程度和控制通气加深麻醉的效果进行量化描述。方法选择无呼吸系统及神经系统疾病的全麻小儿20例(4.3±1.5y,17.95±5.12kg),静脉注射氯胺酮1mg/kg,吸入氧气2L/min+7%七氟烷麻醉诱导,应用恒温热线风速仪分别采集四个时间段呼吸力学数据:静注氯胺酮1分钟后(T1);开始吸入7%七氟烷时(T2);吸入7%七氟烷3分钟后(T3);控制通气2分钟后(T4)。结果①T2较T1吸气相和呼气相最大流速、平均流速、平均流量、平均动压、呼吸频率均增加(P<0.05或P<0.01),而吸气时间、呼气时间均缩短(P<0.05或P<0.01)。②T3较T1吸气相和呼气相最大流速、平均流速、平均流量、平均动压及呼吸频率均减小(P<0.01);T3较T2吸气时间和呼气时间明显延长(P<0.01),平均吸气速度与最大吸气速度之比、平均呼气速度与最大呼气速度之比均减小(P<0.01)。③T4较T1吸气相和呼气相最大流速、平均流速、平均流量、平均动压及呼吸频率均进一步减小(P<0.01),平均吸气速度与最大吸气速度之比、平均呼气速度与最大呼气速度之比均减小(P<0.01)。结论小儿7%七氟烷麻醉诱导随着持续吸入时间的增加,各项呼吸力学指标出现相应的变化,证明其对呼吸的影响是由兴奋到抑制程度逐渐加深之过程,麻醉诱导中经过控制通气吸入七氟烷加深麻醉效果明显。

Objective To observe the respiratory mechanics changes in upper airway at the different phases of sevoflurane inhalational induction with anemometer in children for the quantization delineation of respiratory suppression degree by sevoflurane and the effect of anesthesia deepened by controlled ventilation. Methods 20 children（4.3±1.5y,17.95±5.12kg） without any diseases in both respiratory and nervous system undergoing general anesthesia were induced with intravenous injection of ketamine 1mg/kg and inhalation of O22L/min＋7% sevoflurane. The respiratory mechanics parameters during four time phases of anesthesia induction were recorded with an anemometer：T1-1 minute after intravenous injection of ketamine; T2-the initiation of sevoflurane inhalation;T3-3 minutes after sevoflurane inhalation;T4-2 minutes after controlled ventilation. Results ①The parameters of T2 compared with that of T1 such as maximum velocities、 mean velocities、mean flow volumes、 mean velocity pressure of inspiratory/expiratory airflow and respiratory frequency markedly increased respectivedly（P〈0.05orP〈 0.01）.The time of inspiratory/expiratory phase was shorter in T2 than in T1. （P〈0.05 or P〈0.01）; ② The parameters of T3 compared with that of T1 such as maximum velocities、 mean velocities、mean flow volumes、mean velocity pressure of inspiratory/expiratory airflow and respiratory frequency evidently fell down respectivedly （P 〈0.01）.The time of inspiratory/ expiratory phase was longer in T3 than in T2 （P〈0.01）.In T3 the relative value of mean velocities and maximum velocities on inspiratory/expiratory phase remarkably reduced.（P〈0.01）.③The parameters of T4 compared with that of T1 such as maximum velocities、 mean velocities、mean flow volumes、mean velocity pressure of inspiratory/expiratory airflow and respiratory frequency evidently further fell down （P〈0.01）.The relative value of mean velocities and maximum velocities on inspiratory/ expiratory phase remarkably reduced （P〈0.01）.Conclusion Along with 7% Sevoflurane inhalation induction coming on in children,the all parameters of respiratory mechanics were made corresponding changes.That could prove that the effect of sevoflurane on respiration is the process from excitation to inhibition by degrees.It has obvious effect that anesthesia induction was deepened with inhalational sevoflurane by controlled ventilation.