侧卧折刀位对动脉血-呼气末二氧化碳分压差的影响

Effects of the lateral positioning plus jackknife positioning on difference of partial pressure of carbon dioxide in artery and end-tidal pressure of carbon dioxide

目的 观察侧卧折刀位对动脉血-呼气末二氧化碳分压差[difference of partial pressure of carbon dioxide in artery and end-tidal pressure of carbon dioxide,P（a-ET）CO2]的影响. 方法 36例择期手术患者分为两组（每组18例）∶对照组（C组）为择期行腹部手术患者,术中一直为仰卧位;实验组（L组）为择期行肾脏切除术、输尿管切开取石术或肾上腺囊肿切除术等患者,术中需要仰卧位变为侧卧折刀位.两组患者均采用全凭静脉麻醉,气管插管后机械通气,设置呼吸频率15次/min,吸呼比1∶1.5,维持呼气末二氧化碳分压（end-tidal pressure of carbon dioxide,PETCO2）在30 mmHg～35 mmHg（1 mmHg=0.133 kPa）之间.两组患者在PETCO2稳定（波动不超过1 mmHg）（T0）后15 min时（T1）和35 min时（T2）行动脉血气分析,期间不调整呼吸参数.L组于T1时仰卧位改为侧卧折刀位,而C组仰卧位不变.术中常规监测心电图、心率、脉搏血氧饱和度、有创血压、潮气量、气道峰压、分钟通气量、PETCO2等. 结果 L组T2时PETCO2、动脉血二氧化碳分压（partial pressure of carbon dioxide in artery,PaCO2）和p（a-ET）CO2分别为（28.4±2.3）、（35.7±3.3）、（7.2±3.0）mmHg,而L组T1时分别为（32.2±1.8）、（34.2±2.0）、（2.6±2.8） mmHg,差异有统计学意义（P＜0.05）.C组T1和T2时P（a-ET）CO2分别为（2.6±2.5）、（3.1±1.5）mmHg,均低于L组T2时的P（a-ET）CO2（P＜0.05）. 结论 侧卧折刀位体位显著增加P（a-ET）CO2,根据PETCO2指导调整呼吸参数时,应降低其数值.

Objective To observe the effects of lateral position plus jacknife position on difference of partial pressure of carbon dioxide in artery and end-tidal pressure of carbon dioxide[P（a-ET）CO2].Methods Thirty-six patients undergoing elective surgery under total intravenous anesthesia were involved.Patients were divided into two groups （n=18）：control group （group C） and experimental group （group L）.Patients undergoing abdominal surgery were at supine position in group C.Patients undergoing nephrectomy,ureterolithotomy surgery or adrenal cyst resection were at lateral position plus jacknife position.Patients were endotracheal intubation and mechanical ventilation,respiratory rate was 15 rpm,inspiratory/expiratory ratio was 1∶1.5.End-tidal pressure of carbon dioxide（PETCO2） was stable between 30 mmHg-35 mmHg （1 mm Hg=0.133 kPa）.Blood gas analysis was done at 15 （T1）,35 min （T2） and PETCO2 was stable （T0）（the fluctuation was less than 1 mmHg）.The ventilator parameters were not been constant during T0-T2 At T1,patients＇ position were changed from supine position to lateral position plus jacknife position in group L,and patients＇ position remained supine position in group C.Intraoperative monitoring consisted of electrocardiogram,invasive arterial pressure,heart rate,pulse oxygen saturation,tidal volume,minute ventilation,peak of airway pressure,end-tidal pressure of carbon dioxide（PETCO2）,and so on.Results PETCO2,partial pressure of carbon dioxide in artery（PaCO2） and P（a-ET）CO2 were respectively （28.4±2.3）,（35.7±3.3）,（7.2±3.0） mmHg at T2 in group L.In group L,those items were（32.2± 1.8）,（34.2±2.0）,（2.6±2.8） mmHg at T1 respectively（P〈O.05）.P（a-ET）CO2 were（2.6±2.5） and （3.1 ±1.5） mmHg at T1 and T2 respectively in group C.Compared with group L,P （aET）CO2 were significantly lower （P〈0.05）.Conclusions P （a-ET）CO2 was significantly increases at lateral position plus jacknife position.So the ventilator parameters should be adjusted according PETCO2.