压力容积曲线指导PEEP通气对截石位腹腔镜手术患者脑血流的影响

目的 观察压力容积曲线（pressure-volume curve,P-V环）指导呼气末正压（positive end-expiratory pressure,PEEP）小潮气量通气对CO2气腹截石位手术患者脑血流的影响.方法 将全麻下行CO2气腹截石位择期手术患者50例（TNM分期Ⅰ～Ⅲ期直肠癌根治术11例、子宫肌瘤全宫切除术39例）（ASA Ⅰ～Ⅱ级）,随机分为2组,对照组（A组）和P-V环组（B组）,每组25例.气腹前,两组通气参数设定：潮气量（VT）为8 ml/kg,呼吸频率（RR）12次/min,吸呼比1：2.气腹后A组通气参数不变;B组通气参数：PEEP值（PLIP＋VT）为6 ml/kg,RR 18次/min.于气腹前（T0）、气腹后30 min（T1）、60 min（T2）测呼气末CO2分压（PETCO2）、气道峰压（Ppeak）、平均气道压（Pmean）;测定心率和平均动脉压;颈内静脉球部和桡动脉采血行血气分析,检测动脉血氧分压（PaO2）、动脉二氧化碳分压（PaCO2）、动脉血氧饱和度（SaO2）、颈内静脉血氧分压（PjvO2）、颈内静脉血氧饱和度（SjvO2）、颈内静脉血氧含量（CjvO2）,根据Fick公式计算动脉-颈内静脉血氧含量差（Ca-jvDO2）.结果 组内比较：与T0相比,两组T1、T2时MAP、HR、Pmean、Ppeak、PETCO2、PaCO2、PjvO2、SjvO2、CjvO2明显升高（P＜0.05）,而两组T1、T2时PaO2、Ca-jvDO2均显著减小（P＜0.05）.组间比较：与A组相比,B组T1、T2时Pmean 、PETCO2、PaCO2、SjvO2均明显增高（P＜0.05）,而Ppeak均显著减小（P＜0.05）,B组T1时Ca-jvDO2显著减小（P＜0.05）.结论 P-V环指导下PEEP值、小潮气量通气可以改善CO2气腹截石位手术患者的脑血流量和脑氧供需平衡.

Effects of positive end-expiratory pressure ventilation guided by pressure-volume curve on cerebral blood flow of patient undergoing gynecological laparoscopic surgery in lithotomy position

Objective To observe the effects of positive end-expiratory pressure ventilation guided by pressure-volume curve on cerebral blood flow of patients undergoing gynecological laparoscopic surgery in lithotomy position. Methods Fifty patients （ASA I -II） scheduled to undergo gynecological laparoscopic surgery under general anesthesia were randomly divided into two groups （ using random number table, n = 25 ） ： control group （Group A） and P-V curve group （Group B）. Before pneumoperitoneum,the tidal volume （VT） of all patients was set as 8 ml/kg, respiratory rate （RR） 12 times/min, and respiratory ratio 1：2. After pneumoperitoneum,patients in Group A maintained the previous parameters, while patients in group B were adjusted as follow：PEEP （PLIP ＋ ~T ）of 6ml/kg, RR of 18 times/min. End-tidal partial pressure of CO2 （P~rC02）, peak airway pressure the （Ppeak）, and mean airway pressure （Pmean） were measured, heart rate （HR） and mean arterial pressure（MAP） were monitored and recorded;samples of right radial artery and right internal jugular vein were obtained to measure arterial oxygen pressure （ PaO2 ）, arterial carbon dioxide partialpressure （ PaCO2 ）, internal jugular venous blood oxygen partial pressure （ PjvO2 ）, internal jugular venous oxygen saturation （ SjvO2 ） , and jugular vein oxygen content （ CjvO2 ）, and the arterial- internal jugular venous blood gas oxygen content （Ca-jvDO2） was calculated according to Fick＇s formula before pneumoperitoneum （To） ,30 min（T1） and 60 min（T2）after pneumoperitoneum. Results In paired comparisons,compared with TO, the MAP, HR, Pmean, Ppeak, PET CO2, PaCO2, PjvO2, SjvO2, and CjvO2 of two groups at T1 and T2 were significantly increased （P 〈 0.05 ）, while PaO2 and Ca-jvDO2 were significantly reduced （ P 〈 0.05）. PET CO2, Pmean, PaCO2, and SjvO2 of group B at T1 and T2 were significantly higher than those of group A （ P 〈 0.05 ）, while Ppeak significantly reduced （ P 〈 0. 05 ）, and so did Ca-jvDO2 of group B at T1. Conclusions Positive end-expiratory pressure ventilation with low tidal volume guided by pressure-volume curve can improve the cerebral blood flow, balance of cerebral oxygen supply, and demand of patients undergoing gynecological laparoseopic surgery in lithotomy position.