Vadeboncouer T R, Riegler F X, Pelligrino D A
Department of Anesthesiology, Michael Reese Hospital, Chicago, IL 60616.
Reg Anesth. 1990 Mar-Apr;15(2):67-72.
The effect of increasing interpleural injectate volume was determined in a chronic canine model. Changes in evoked potentials were used as a marker of nerve blockade. Electrodes were fastened to the right fifth, seventh and ninth ribs of adult dogs at distal (D), middle (M) and proximal (P) sites. Electrodes were also fastened to the ipsilateral laminae of the fifth (T5L), seventh (T7L) and ninth (T9L) thoracic vertebrae. Evoked potentials were recorded at each lamina after stimuli were applied to the corresponding distal, middle and proximal rib electrodes. Interpleural catheters were placed under direct vision during surgery. The effects of 10 ml and 20 ml of 0.5% bupivacaine were studied for each dog. Following 10 ml of 0.5% bupivacaine, intercostal nerve block was produced at T5 and T7, as evidenced by decreases in amplitude (range, 6-53% of control, p less than 0.05) and increases in latency (range, 108-122% of control, p less than 0.05) of evoked potentials recorded between laminae and distal or middle electrodes. No significant changes were seen in any potentials recorded over T9. After 20 ml of 0.5% bupivacaine, all T5 potentials were abolished. Significant decreases in amplitude (range, 22-36% of control, p less than 0.05) and increases in latency (range, 117-126% of control, p less than 0.05) were produced at all T7 rib sites. Except for the D-T7L comparison, all T5 and T7 changes produced by 20 ml of bupivacaine were greater (p less than 0.05) than those produced by 10 ml. Twenty milliliters of bupivacaine also produced decreases in amplitude (range, 41-51% of control at all sites, p less than 0.05) and increases in latency (115% at D-T9L, p less than 0.05) at T9 sites. Twenty milliliters of 0.5% bupivacaine produces intercostal nerve block that is more pronounced and widespread than that produced by 10 ml of bupivacaine.
在慢性犬模型中确定了增加胸膜间注射量的效果。诱发电位的变化被用作神经阻滞的标志物。将电极固定在成年犬右侧第五、第七和第九肋骨的远端（D）、中间（M）和近端（P）部位。电极还固定在第五（T5L）、第七（T7L）和第九（T9L）胸椎的同侧椎板上。在对相应的远端、中间和近端肋骨电极施加刺激后，在每个椎板记录诱发电位。在手术过程中直视下放置胸膜间导管。对每只犬研究了10毫升和20毫升0.5%布比卡因的效果。注入10毫升0.5%布比卡因后，T5和T7处产生了肋间神经阻滞，这表现为椎板与远端或中间电极之间记录的诱发电位幅度降低（范围为对照的6 - 53%，p < 0.05）以及潜伏期延长（范围为对照的108 - 122%，p < 0.05）。在T9记录的任何电位均未观察到显著变化。注入20毫升0.5%布比卡因后，所有T5电位均被消除。所有T7肋骨部位的幅度显著降低（范围为对照的22 - 36%，p < 0.05）以及潜伏期延长（范围为对照的117 - 126%，p < 0.05）。除了D - T7L比较外，20毫升布比卡因引起的所有T5和T7变化均大于（p < 0.05）10毫升布比卡因引起的变化。20毫升布比卡因还使T9部位的幅度降低（所有部位范围为对照的41 - 51%，p < 0.05）以及潜伏期延长（D - T9L处为115%，p < 0.05）。20毫升0.5%布比卡因产生的肋间神经阻滞比10毫升布比卡因产生的更明显且更广泛。
