Anesthesiology. 2020 Oct 1;133(4):750-763. doi: 10.1097/ALN.0000000000003442.
Body habitus, pneumoperitoneum, and Trendelenburg positioning may each independently impair lung mechanics during robotic laparoscopic surgery. This study hypothesized that increasing body mass index is associated with more mechanical strain and alveolar collapse, and these impairments are exacerbated by pneumoperitoneum and Trendelenburg positioning.
This cross-sectional study measured respiratory flow, airway pressures, and esophageal pressures in 91 subjects with body mass index ranging from 18.3 to 60.6 kg/m2. Pulmonary mechanics were quantified at four stages: (1) supine and level after intubation, (2) with pneumoperitoneum, (3) in Trendelenburg docked with the surgical robot, and (4) level without pneumoperitoneum. Subjects were stratified into five body mass index categories (less than 25, 25 to 29.9, 30 to 34.9, 35 to 39.9, and 40 or higher), and respiratory mechanics were compared over surgical stages using generalized estimating equations. The optimal positive end-expiratory pressure settings needed to achieve positive end-expiratory transpulmonary pressures were calculated.
At baseline, transpulmonary driving pressures increased in each body mass index category (1.9 ± 0.5 cm H2O; mean difference ± SD; P < 0.006), and subjects with a body mass index of 40 or higher had decreased mean end-expiratory transpulmonary pressures compared with those with body mass index of less than 25 (-7.5 ± 6.3 vs. -1.3 ± 3.4 cm H2O; P < 0.001). Pneumoperitoneum and Trendelenburg each further elevated transpulmonary driving pressures (2.8 ± 0.7 and 4.7 ± 1.0 cm H2O, respectively; P < 0.001) and depressed end-expiratory transpulmonary pressures (-3.4 ± 1.3 and -4.5 ± 1.5 cm H2O, respectively; P < 0.001) compared with baseline. Optimal positive end-expiratory pressure was greater than set positive end-expiratory pressure in 79% of subjects at baseline, 88% with pneumoperitoneum, 95% in Trendelenburg, and ranged from 0 to 36.6 cm H2O depending on body mass index and surgical stage.
Increasing body mass index induces significant alterations in lung mechanics during robotic laparoscopic surgery, but there is a wide range in the degree of impairment. Positive end-expiratory pressure settings may need individualization based on body mass index and surgical conditions.
体态、气腹和头低脚高位可能会各自独立地影响机器人腹腔镜手术中的肺力学。本研究假设体重指数增加与更多的机械应变和肺泡萎陷有关，并且这些损伤会因气腹和头低脚高位而加重。
本横断面研究测量了 91 名体重指数在 18.3 至 60.6kg/m2 之间的受试者的呼吸流量、气道压力和食管压力。在四个阶段量化了肺力学：（1）插管后仰卧位和水平位，（2）气腹，（3）与机器人对接的头低脚高位，（4）无气腹的水平位。受试者被分为五个体重指数类别（<25、25-29.9、30-34.9、35-39.9 和≥40），并使用广义估计方程比较了手术阶段的呼吸力学。计算了实现正呼气末跨肺压力所需的最佳呼气末正压设置。
在基线时，每个体重指数类别中的跨肺驱动压都增加（1.9 ± 0.5cmH2O；平均差异±标准差；P < 0.006），体重指数为 40 或更高的受试者的平均呼气末跨肺压力低于体重指数<25 的受试者（-7.5 ± 6.3 与-1.3 ± 3.4cmH2O；P < 0.001）。气腹和头低脚高位分别进一步升高跨肺驱动压（分别为 2.8 ± 0.7 和 4.7 ± 1.0cmH2O；P < 0.001）和降低呼气末跨肺压力（分别为-3.4 ± 1.3 和-4.5 ± 1.5cmH2O；P < 0.001）与基线相比。与基线相比，79%的受试者在基线时的最佳呼气末正压大于设定的呼气末正压，88%的受试者在气腹时，95%的受试者在头低脚高位时，最佳呼气末正压的范围为 0 至 36.6cmH2O，取决于体重指数和手术阶段。
体重指数增加会导致机器人腹腔镜手术中肺力学发生显著改变，但损伤程度存在很大差异。根据体重指数和手术条件，呼气末正压设置可能需要个体化。
