全麻诱导期不同吸氧浓度对气管插管时无通气安全时限的影响

Effect of different oxygen inhalation concentrations on safe duration of apnea during tracheal intubation under general anesthesia

目的探索全麻诱导期不同吸氧浓度对气管插管时无通气安全时限的影响。方法选择80例ASAⅠ到Ⅱ级在气管插管全麻下行择期手术患者,根据全麻醉诱导时面罩通气吸入氧浓度(fraction of inspired oxygen,FIO_(2)),采用随机数字法将患者分为4组:A组(FIO_(2)=1,n=20)、B组(FIO_(2)=0.8,n=20)、C组(FIO_(2)=0.6,n=20)、D组(FIO_(2)=0.4,n=20)。面罩通气和气管插管均由三位有经验的麻醉医生进行操作完成,由助手进行气体浓度调整和脉搏氧饱和度(SPO_(2))及相关指标的观察记录。各组气管插管操作完成后均不予通气,直至SPO_(2)降至90%。在气管插管未完成时SPO_(2)降至90%以下,则认定为失败病例。记录失败病例数,无通气安全时限(即无通气状态下SPO_(2)≥90%的持续时间)及气管插管时长。结果各组均无失败病例,无通气安全时限分别为A组(493.5±172.8)s,B组(380.9±93.7)s,C组(276.3±103.2)s,D组(160.3±54.8)s,气管插管时长分别为(38.4±9.8)s,(32.8±7.5)s,(36.8±9.0)s,(35.9±10.3)s。无通气安全时限和气管插管时长的99%置信区间分别为A组(382.9,604.0)s、(32.1,44.6)s,B组(320.9,440.9)s、(27.9,37.6)s,C组(210.2,342.2)s、(31.0,42.5)s,D组(125.3,195.3)s、(29.3,42.5)s。各组的无通气安全时限均显著大于气管插管时长(P<0.01)。四组间的气管插管时长的差异以及气管插管完成时SpO_(2)≥90%例数的差异均无统计学意义(P>0.05)。结论对于有经验的麻醉医师,全麻诱导时面罩通气吸入氧浓度为40%即可提供充足的无通气安全时限以便完成气管插管。

Objective To investigate the effect of different oxygen inhalation concentrations on safe duration of apnea during tracheal intubation under general anesthesia.Methods Eighty patients with ASA grades I to II underwent elective surgery during tracheal intubation under general anesthesia.According to the fraction of inspired oxygen(FIO_(2))during mask ventilation under general anesthesia,all patients were randomly divided into 4 groups:group A(FIO_(2)=1,n=20),group B(FIO_(2)=0.8,n=20),group C(FIO_(2)=0.6,n=20),and group D(FIO_(2)=0.4,n=20).The mask ventilation and tracheal intubation were performed by three experienced anesthesiologists.The oxygen concentration,pulse oxygen saturation(SPO_(2))and related indicators were adjusted by the assistants.The ventilation was not completed after the performance of tracheal intubation in each group until the SPO_(2) was reduced to 90%.Cases were deemed as failure where the SPO_(2) decreased below 90%before the tracheal intubation was completed.The number of failure cases,safe duration of apnea(duration of SPO_(2)≥90%without ventilation)and duration of tracheal intubation were recorded.Results There was no failure case in each group.The safe duration of apnea in groups A,B,C and D was(493.4±172.7)s,(380.9±93.7)s,(276.2±103.1)s and(160.30±54.7)s,respectively.The duration of tracheal intubation was(38.3±9.7)s,(32.7±7.5)s,(36.7±9.0)s,and(35.9±10.3)s,respectively.The 99%confidence intervals for safe duration of apnea and duration of tracheal intubation was(382.9,604.0)s and(32.1,44.6)s in group A,(320.9,440.9)s and(27.9,37.6)s in group B,(210.2,342.2)s and(31.0,42.5)s in group C,and(125.3,195.3)s and(29.3,42.5)s in group D.The safe duration of apnea was significantly longer than the duration of tracheal intubation in each group(P<0.01).There were no statistically significant differences in the duration of tracheal intubation and the number of cases with SpO_(2)≥90%before completion of tracheal intubation among the four groups(P>0.05).Conclusion For experienced anesthesiologists,mask ventilation during induction of general anesthesia with 40%FIO_(2) may provide adequate safe duration of apnea to complete tracheal intubation.