不同角度头低位对腹腔镜直肠癌根治术中患者呼吸力学和脑循环的影响

Effects of different head-down tilt angles on respiratory mechanics and cerebral circulation during laparoscopic radical resection of rectal carcinoma

目的 评价不同角度头低位对腹腔镜直肠癌根治术患者呼吸力学和脑循环的影响.方法 腹腔镜直肠癌根治术患者30例,年龄40- 64岁,性别不限,ASA分级Ⅰ或Ⅱ级,体重指数＜30kg/m2.静脉注射咪达唑仑、芬太尼、异丙酚和顺阿曲库铵麻醉诱导,靶控输注异丙酚和瑞芬太尼,按需追加顺阿曲库铵维持麻醉.分别于平卧5 min、头低位30°5 min、头低位35°5 min、头低位40°min和气腹结束后30 min时,记录气道压（Paw）、气道峰压（PIP）、肺顺应性（Cpat）和颈静脉球部压力（JBP）;采集桡动脉血样和颈静脉球血样,进行血气分析,记录动脉血氧分压（PaO2）、动脉血二氧化碳分压（PaCO2）、动脉血氧饱和度（SaO2）、颈静脉球血氧分压（PjvO2）和颈静脉球血氧饱和度（SjvO2）.结果 Paw、PIP、MAP、PaCO2、JBP、PjvO2和SjvO2较平卧位时升高,且随头低位角度的增大逐渐升高,气腹结束后30 min时降至平卧位时水平（P＜ 0.05）;Cpat和PaO2较平卧位时降低,且随头低位角度的增大逐渐降低,气腹结束后30 min时升至平卧位时水平（P＜0.05）.结论 腹腔镜直肠癌根治术时随头低位角度增加对患者呼吸力学和脑循环影响越大,因此此类手术患者头低位的适宜角度为小于40°.

Objective To evaluate the effects of different head-down tilt （HDT） angles on respiratory mechanics and cerebral circulation during laparoscopic radical resection of rectal carcinoma in the patients.Methods Thirty patients of both sexes,aged 40-64 yr,of ASA physical status Ⅰ or Ⅱ,with body mass index 〈 30 kg/m2,scheduled for elective laparoscopic radical resection of rectal carcinoma,were included in the study.Anesthesia was induced with midazolam,fentanyl,propofol and cis-atracurium and maintained with targetcontrolled infusion of propofol and remifentanil and cis-atracurium when needed.At 5 min after supine position,5 min after 30° HDT,5 min after 35° HDT,5 min after 40° HDT,and 30 min after pneumoperitoneum （T1-5）,airway pressure （Paw）,peak airway pressure （PIP）,lung compliance （Cpat） and jugular bulb blood pressure （JBP） were recorded.Blood samples were taken from the radial artery and jugular bulb for blood gas analysis and arterial partial pressure of oxygen （PaO2）,partial pressure of carbon dioxide in artery （PaCO2）,arterial oxygen saturation （SaO2）,jugular bulb oxygen partial pressure （PjvO2）,and jugular bulb venous saturation （SjvO2） were recorded at each time point mentioned above.Results Paw,PIP,MAP,PaCO2,JBP,PjvO2 and SjvO2 were significantly increased as compared with those obtained when the patients were in supine position,increased gradually with the increasing HDT angles,and decreased to the level obtained when the patients were in supine position at 30 min after pneumoperitoneum.Cpat and PaO2 were significantly decreased as compared with those obtained when the patients were in supine position decreased gradually with the decreasing HDT angles,and increased to the level obtained when the patients were in supine position at 30 min after pneumoperitoneum.Conclusion HDT-induced effects on respiratory mechanics and cerebral circulation increase with increasing angles during laparoscopic radical resection of rectal carcinoma; thus the optimum HDT angle is smaller than 40° for the patients undergoing this kind of surgery.