目的 比较不同吸气时间的压力控制通气模式对小儿长时间二氧化碳(CO2)气腹腔镜手术中动脉血氧分压[p(O2)]和动脉血二氧化碳分压[p(CO2)]的影响.方法 预计气腹时间>3 h的腹腔镜手术患儿40例,年龄3个月 ～11岁4个月,ASA分级Ⅰ ～ Ⅱ级.按随机数字表法分为两组,每组20例.T组采用长吸气时间压力控制通气模式通气[吸呼比(I:E)=1:1],C组采用传统的压力控制通气模式(I:E=1:2)通气,其余通气参数设置无差异.术中气腹压(IAP)8～12 mmHg,记录气腹建立前5 min(T0)、气腹1 h(T1)、气腹3 h(T2)、气腹结束前10 min(T3)和气腹结束后10 min(T4)各时间点的心率(HR)、平均动脉压(MAP)、呼气末二氧化碳分压(PET CO2),并行动脉血气分析p(O2)和p(CO2).结果 T组p(CO2)在T2～T4时刻,明显低于C组(P<0.05),高碳酸血症的发生率较低;p(O2)在T1～T4时刻明显高于C组(P<0.05),但均在临床正常值范围内.结论 长吸气时间压力控制通气模式可安全有效地用于小儿长时间CO2气腹腔镜手术中,且在预防高碳酸血症,改善氧合方面更有优势.%Objective To investigate the influence of different I: E ratio pressure controlled ventilation(PCV) mode on p(O2 ) and p(CO2 ) in pediatrics undergoing long time laparoscopic surgery. Methods A total of 40 children underwent laparoscopic surgery with continuous pneumoperitoneum time expected more than 3 hours were randomly assigned into two groups. Group T,ventilated with PCV mode(inspiratory-to-expiratory ratio,I: E = 1: 1),Group C,ventilated with conventional PCV mode(I: E = 1: 2). CO2 insufflation pres-sure was maintained within 8-12 mmHg for pneumoperitoneum creation. The base line parameters of heart rate(HR),mean arterial pres-sure(MAP),partial pressure of end-tidal carbon dioxide(PET CO2 ) were recorded and arterial blood-gas analysis was obtained at various intervals i. e. 5 min before CO2 insufflation(T0 ),and immediately during insufflation 1 hour(T1 ),3 hours(T2 ),10 min before CO2 ex-sufflation(T3 ) and 10 min after CO2 exsufflation(T4 ). The results were evaluated and statistically analyzed. Results p(CO2 ) in group T was less at T2-T4 while p(O2 ) was higher at T1-T4 than those in group C(P < 0. 05),and the incidence of hypercapnia was lower in group T. After CO2 aeroperitonia,HR,MAP,PET CO2 ,p(CO2 ),Lac increased significant while pH decreased statistically significant, while all these dates within normal limits. No clinical and pathological changes were observed. Conclusions Long inspired time PCV mode was safe and effective in pediatrics during long time laparoscopic surgery,which had advantages in improving oxygenation and pre-venting hypercarbia.
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