Pansard J L, Mankikian B, Bertrand M, Kieffer E, Clergue F, Viars P
Département d'Anesthésie-Réanimation and Service de Chirurgie Vasculaire, C.H.U. Pitié-Salpétriêre, Université Paris, France.
Anesthesiology. 1993 Jan;78(1):63-71. doi: 10.1097/00000542-199301000-00011.
Upper abdominal surgery (UAS) induces diaphragmatic dysfunction. Thoracic extradural block (TEB) using 0.5% bupivacaine improves some pressure and motion indices of diaphragmatic function. However, no direct information on diaphragmatic activity is available after UAS. The aim of this study was to assess diaphragmatic electrical activity (Edi) after UAS before and after TEB.
A postoperative electromyogram was obtained, using intramuscular electrodes inserted by the surgeon in the costal and crural parts of the diaphragm, in 14 patients undergoing abdominal aortic surgery. Tidal changes in abdominal (VAB) and rib-cage (VRC) volumes, and gastric (delta Pgas), esophageal (delta Pes), and transdiaphragmatic (delta Pdi) pressures were used to measure tidal volume (VT) and respiratory rate and to provide indirect indices of diaphragmatic activity from the two ratios VAB/VT and delta Pgas/delta Pdi. These respiratory variables were obtained preoperatively. Postoperatively, measurements including Edi were obtained before and after a segmental epidural block, reaching a T4 level was achieved with 0.5% plain bupivacaine.
Upper abdominal surgery induced an increase in respiratory rate (+28 +/- 15%; P < .01), associated with a decrease in VAB/VT (from 0.75 +/- 0.11 to 0.07 +/- 0.08; P < .01), delta Pgas/delta Pdi (from 0.3 +/- 0.08 to 0.01 +/- 0.19; P < .05), and VT (-30 +/- 14%; P < .01). After surgery, all patients exhibited electrical diaphragmatic activity that increased with TEB by 48 +/- 28% (P < .01) and 60 +/- 22% (P < .001) for the cural and costal segments, respectively. The ratio delta Pdi/Edi, used to evaluate diaphragmatic contractility, was not modified by TEB. Tidal volume, respiratory rate, and delta Pgas/delta Pdi returned to preoperative levels, whereas VAB/VT increased but remained different from preoperative values.
This study demonstrates that TEB produces an increase in diaphragmatic activity, identical for the two segments of the muscle. Interruption of afferents that produce an inhibitory effect on diaphragmatic activity appears the most attractive hypothesis to explain the consequences of TEB after UAS.
上腹部手术（UAS）可导致膈肌功能障碍。使用0.5%布比卡因的胸段硬膜外阻滞（TEB）可改善膈肌功能的一些压力和运动指标。然而，UAS后尚无关于膈肌活动的直接信息。本研究的目的是评估UAS前后TEB时的膈肌电活动（Edi）。
对14例行腹主动脉手术的患者，在术后使用外科医生插入膈肌肋部和脚部分的肌内电极获取肌电图。利用腹部（VAB）和胸廓（VRC）容积的潮气量变化，以及胃内压（delta Pgas）、食管压（delta Pes）和跨膈压（delta Pdi）来测量潮气量（VT）和呼吸频率，并通过VAB/VT和delta Pgas/delta Pdi这两个比值提供膈肌活动的间接指标。这些呼吸变量在术前获取。术后，在节段性硬膜外阻滞（使用0.5%的布比卡因达到T4水平）前后进行包括Edi在内的测量。
上腹部手术导致呼吸频率增加（+28±15%；P<.01），同时VAB/VT降低（从0.75±0.11降至0.07±0.08；P<.01），delta Pgas/delta Pdi降低（从0.3±0.08降至0.01±0.19；P<.05），VT降低（-30±14%；P<.01）。术后，所有患者均表现出膈肌电活动，TEB后膈肌脚段和肋段的电活动分别增加48±28%（P<.01）和60±22%（P<.001）。用于评估膈肌收缩力的delta Pdi/Edi比值未因TEB而改变。潮气量、呼吸频率和delta Pgas/delta Pdi恢复到术前水平，而VAB/VT虽增加但仍与术前值不同。
本研究表明TEB可使膈肌活动增加，且对膈肌的两个节段作用相同。对膈肌活动产生抑制作用的传入神经中断似乎是解释UAS后TEB效果的最有吸引力的假说。
