体重指数对全麻患者机械通气期间潮气量设置的影响

目的探讨体重指数对全麻患者机械通气期间潮气量设置的影响。方法 90例ASA分级I-Ⅱ级、年龄在20-60岁、拟行气管插管全麻下行择期手术的患者,分为轻体重组（L组,体重指数BMI〈18.5 kg/m^2,28例）,正常体重组（N组,18.5 kg/m^2≤BMI〈23 kg/m^2,32例）,超重或肥胖组（H组,BMI≥23 kg/m^2,30例）。3组患者在全麻气管插管后,调整潮气量,维持呼气末二氧化碳分压在35-45 mmHg,记录麻醉前（T0）、潮气量调整稳定后5 min（T1）、10 min（T2）、15 min（T3）、20 min（T4）、30 min（T5）、60 min（T6）的心率（HR）、平均动脉压（MAP）、脉搏血氧饱和度（SpO2）、吸入潮气量（VTi）、呼出潮气量（VTe）、呼气末二氧化碳分压（PETCO2）、气道峰压（Ppeak）。结果 3组患者在T1-6各时间点MAP、HR、SpO2差异均无统计学意义。与N组和L组相比,H组各时间点的VTi、VTe均较低,Ppeak均较高（P〈0.05）;与L组相比,N组各时间点的VTi、VTe均较低,Ppeak均较高（P〈0.05）。H组各时间点的PETCO2要低于N组和L组（P〈0.05）,N组和L组的PETCO2差异无统计学意义。结论轻体重患者全麻机械通气期间所需要的潮气量要大于正常体重患者,超重和肥胖患者全麻机械通气期间所需要的潮气量要小于正常体重患者。BMI是患者全麻机械通气期间潮气量设置的重要参考指标。

Effect of body mass index on tidal volume with controlled mechanical ventilation during general anesthesia

Objective To evaluate the effect of body mass index（BMI） on tidal volume with controlled mechanical ventilation during general anesthesia. Methods Ninety patients with ASA（American Society of Anesthesiologists） gradeⅠ orⅡ,20-60 years old and scheduled for elective surgery under general anesthesia,were selected in the study and divided into 3 groups, light weight group（L group, BMI 〈18.5 kg/m^2, 28 cases）, normal weight group（N group, 18.5 kg/m^2≤ BMI 〈23 kg/m^2, 32 cases）,and overweight or obesity group（H group, BMI ≥23 kg/m^2, 30 cases）. Partial pressure of end-tidal carbon dioxide（PETCO2） were maintained between 35-45 mmHg by adjusting tidal volume after indubation, the parameters including mean arterial pressure（MAP）,heart rate（HR）, pulse oxygen saturation（SpO2）, partial pressure of end-tidal carbon dioxide（PETCO2）, inspiratory tidal volume（VTi）, expiratory tidal volume（VTe）, peak inspiratory pressure（Ppeak） were recorded 5, 10, 15, 20, 30 and 60 minutes after adjusting tidal volume. Results There were no statistical differences in MAP, HR, and SpO2 in the three groups. Compared with N and L group, VTi and VTe were significantly lower in group H（P〈0.05）. Ppeak was higher in groupH（P〈0.05）. Compared with L group, VTi and VTe were significantly lower in group N（P〈0.05）. Ppeak was higher in group N（P〈0.05）. Compared with N and L group, PETCO2 was lower in group H（P〈0.05）. There were no statistical differences between N and L group. Conclusions Patients of light weight require more tidal volume, and patients of overweight or obesity require less tidal volume than patients of normal weight. BMI is an important factor for setting up tidal volume with controlled mechanical ventilation during general anesthesi.