肺功能正常的肥胖患者全身麻醉时应用校正体质量设置潮气量的可行性评价

目的 评价肺功能正常的肥胖患者全身麻醉时应用校正体质量设置机械通气潮气量的可行性.方法 选择2008年1月至2013年12月收治的肥胖患者96例,拟全身麻醉下择期手术,ASA分级Ⅰ或Ⅱ级,采用随机数字表法将其分成三组：实际体质量设置潮气量组（A组）、理想体质量设置潮气量组（B组）和校正体质量设置潮气量组（C组）,每组32例.麻醉诱导后气管插管,根据相应体质量水平,按8 ml/kg设置机械通气初始潮气量,呼吸频率15次/min.于机械通气开始后10 min记录气道峰压（Ppeak）、气道平台压（Pplat）和气道阻力（Raw）,机械通气30 min时采集动脉血行血气分析,并记录动脉血氧分压（PaO2）、动脉血二氧化碳分压（PaCO2）及患者需调整潮气量的发生情况.结果 与A组比较,B组和C组Ppeak、Pplat、Raw降低（15.3±1.8）,（18.5±2.6） cmH2O（1 cmH2O=0.098 kPa）比（23.2±3.3） cmH2O,（11.5±1.6）,（14.3±1.4） cmH2O比（17.6±2.7） cmH2O,（10.8±1.7）,（12.5±2.6）cmH2O/ （L·s）比（16.8±3.0） cmH2O/ （L·s）],PaCO2升高（48.8±3.1）,（40.2±2.3） mmHg（1 mmHg=0.133 kPa）比（28.6±3.8） mmHg],差异均有统计学意义（P＜0.01）;与B组比较,C组Ppeak、Pplat、Raw升高,PaCO2降低,差异有统计学意义（P＜0.01）;三组患者PaO2和氧合指数比较差异无统计学意义（P＞0.05）.患者需调整潮气量的发生率,C组未发生,A组（93.8％,30/32）和B组（81.2％,26/32）明显升高,差异有统计学意义（P＜0.01）.结论 肺功能正常的肥胖患者全身麻醉机械通气时,根据校正体质量8 ml/kg设置潮气量是可行的.

Feasibility of using corrected body weight to set tide volume for mechanical ventilation during general anesthesia in obese patients

Objective To evaluate the feasibility of using corrected body weight to set the tide volume for mechanical ventilation during general anesthesia in obese patients.Methods Ninety-six ASA physical status Ⅰ or Ⅱ obese patients,with a body mass index of 28-44 kg/m2,scheduled for elective extremity surgery under general anesthesia,were divided into 3 groups （32 cases of each group） by random digits table method：tide volume based on actual body weight group （group A）,tide volume based on ideal body weight group（group B）,and tide volume based on corrected body weight group（group C）.The pulmonary function of all patients was normal.The patients were endotracheally intubated and mechanically ventilated after induction of anesthesia.According to the corresponding body weight,the initial tide volume was set based on 8 ml/kg in each group（respiratory rate：15 bpm）.At 10 min after start of mechanical ventilation,peak airway pressure （Ppeak）,airway plateau pressure （Pplat）,airwayresistance （Raw） were recorded.Arterial blood samples were collected at 30 min of mechanical ventilation for blood gas analysis and arterial blood oxygen partial pressure （PaO2）,arterial blood carbon dioxide partial pressure （PaCO2） and the patients requiring readjustment of tide volume were also recorded.Results The level of Ppeak,Pplat,Raw in group B and group C were significantly lower than those in group A（15.3 ± 1.8）,（18.5 ± 2.6） cmH2O （1 cmH2O =0.098 kPa） vs.（23.2 ±3.3） cmH2O; （11.5 ± 1.6）,（14.3 ± 1.4） cmH2O vs.（17.6 ±2.7） cmH2O; （10.8 ± 1.7）,（12.5 ± 2.6） cmH2O/ （L·s） vs.（16.8 ± 3.0） cmH2O/ （L·s）],and the level of PaCO2 in group B and group C was significantly higher than that in group A （48.8 ± 3.1）,（40.2 ± 2.3） mmHg （1 mmHg =0.133 kPa） vs.（28.6 ± 3.8） mmHg],there was significant difference（P 〈 0.01）.The level of PaO2 and oxygenation index in three groups had no significant difference （P 〉 0.05）.There were no