容量控制通气模式和压力控制通气模式对病态肥胖症患者循环功能的影响

Effects of volume controlled ventilation and pressure controlled ventilation on morbidly obese patients

目的 探讨病态肥胖症患者行全麻腹腔镜胃旁路术时,容量控制通气模式（volumecontrolled ventilation,VCV）和压力控制通气模式（pressure controlled ventilation,PCV）对患者循环功能的影响.方法 本前瞻性研究对象为2013年9月至2015年3月在暨南大学附属第-医院行腹腔镜Rouxen-Y胃旁路术的40例病态肥胖症患者.采用随机数字表法将患者分为VCV组和PCV组.VCV组20例,男12例,女8例;平均年龄（40±12）岁.PCV组20例,男11例,女9例;平均年龄（34±16）岁.所有患者均签署知情同意书,符合医学伦理学规定.两组患者在气管插管全身麻醉后采用不同的通气模式维持呼吸末PaCO2在35~40 mmHg水平.分别于气腹前（T1）、气腹后30 0 min（ T2）、气腹后60 min（ T3）、气腹后90 min（T4）、停止气腹后30 min （T5）采集桡动脉血进行血气分析,记录两组不同时点的动脉血pH值和PaCO2,并在T1、T2时刻测定血清乳酸（lactic acid,Lac）水平.在麻醉诱导前（T0）、T1、T2和手术后2 h（ T6）采用心脏超声监测记录左心室射血分数（left ventricular ejection fraction,LVEF）和每搏输出量（ stroke volume,SV）.比较两组患者在不同时间点上述指标的测量值.两组患者性别的比较采用χ2检验,其他组间与组内临床指标的比较采用t检验.结果 T1时,两组pH值均高于同组其他时点,PaCO2均低于同组其他时点（P〈0.05）,而两组间各时点pH值和PaCO2比较差异无统计学意义（P〉0.05）;VCV组T2时的Lac浓度明显高于T1（ t=2.751,P〈0.05）,而PCV组T1与T2比较Lac浓度差异无统计学意义（t=0.846, P〉0.05）;T1、T2时,PCV组SV均明显高于VCV组（t=4.983, P〈0.05; t=6.437, P〈0.05）;两组间各时点LVEF比较差异无统计学意义（P〉0.05）.结论 病态肥胖症患者在行腹腔镜Roux-en-Y胃旁路术时,PCV较VCV更有利于降低气腹对循环功能的影响.

Objective To investigate the effects of volume controlled ventilation(VCV) and pressure controlled ventilation(PCV) on morbidly obese patients during LRYGB under general anesthesia. MethodsA total of 40 morbidly obese patients undergoing laparoscopic Roux-en-Y gastric bypass in the First Affiliated Hospital of Jinan University between September 2013 and March 2015 were included in this prospective study. These patients were divided into VCV group and PCV group according to the random number table method. Twenty patients were included into VCV group, among them, 12 were males and 8 were females with an average age of(40±12) years old. Twenty other patients were included into PCV group, among them, 11 were males and 9 were females with an average age of(34±16) years old. The informed consents of all patients were obtained the local ethical committee approval had been received. The two different ventilation modes were used in patients after intubation anesthesia to maintained an end-tidal Pa CO_2 of 35~40 mm Hg. Radial arterial blood was collected for blood gas analysis before pneumoperitoneum(T_1), 30 min(T_2), 60 min(T_3) and 90 min(T_4) after the beginning of pneumoperitoneum, and 30 min(T_5) after pneumoperitoneum termination. Arterial p H value and Pa CO_2 in two groups were collected at different time points, and lactic acid(Lac) levels were measured at T_1 and T_2. Echocardiographic monitoring was used to record left ventricular ejection fraction(LVEF) and stroke volume(SV) before anesthesia induction(T_0), T_1, T_2 and 2 h postoperatively(T_6). Those indexes at different time points were compared between the two groups. The comparison of gender was conducted using Chi-square test, and the comparison of the other clinical indexes among the groups and in the same groups were conducted using t test. Results PH values at T_1 point were higher than those at other time points in both two groups, while Pa CO_2 were lower than those at other time points(P<0.05). As for the comparisons of p H values and Pa CO_2 between the two groups, the differences were not statistically significant(P>0.05). In VCV group, Lac at T_2 was significantly higher than that at T_1(t=2.751, P<0.05). In PCV group, the difference of Lac at T_1 and T_2 was not statistically significant(t=0.846, P>0.05). SV at T_1 and T_2 were higher in PCV group than those in VCV groups(t=4.983, P<0.05; t=6.347, P<0.05). The differences between the two groups in LVEF levels at all time points were not statistically significant(P>0.05). Conclusions PCV does better to reduce the impact of pneumoperitoneum on circulatory function than VCV in morbidly obese patients during laparoscopic Roux-en-Y gastric bypass.