Lidocaine 0.5% tetracaine is used to correct the epidural block of tachyphylaxis, with the exact effect being K1 promethazine at 0.4 to 0.5 mg per kg or droperidol at 0.04 to 0.05 mg per kg (efficiency 0.05). In a group of eight cases under anesthetic effect, two cases had incomplete muscle relaxation but were still able to complete surgery. Ten cases required auxiliary fentanyl, droperidol, and hydroxybutyrate for satisfaction, completing the surgery with ketamine intravenous anesthesia, while four cases switched to venous inhalation anesthesia. Among 28 cases, 2 had good results, 3 cases had better muscle relaxation after additional administration. The good rate between Group 1 and Group 2 showed P < 0.005 early amount resistance time, with the shortest being 30 minutes and the longest being 320 minutes, averaging 128 ± 78 minutes, where 12 cases were less than 45 minutes. This generally occurs after the 4th to 5th administration, no later than the 8th administration. Group 1 had the longest duration of anesthesia at 155 minutes when switching to tetracaine, administered three times, whereas Group 2 had a duration of 400 minutes with five administrations.
[Article ID 11619-0774 7-067-014 (2007)] Discussion on rapid drug resistance refers to a situation where, over a short period, repeated use of local anesthetics leads to weakened nerve block performance, shortened aging, continuous epidural block, and even narrowing within the scope of blocked segments tending towards II~ ~. Epidural anesthesia is the most widely used method in clinical practice, especially in small and medium-sized medical units. Lidocaine is a commonly used local anesthetic that is prone to resistance upon repeated application [131]. Promptly correcting this resistance after discovery has proven challenging due to the lack of an exact, simple, and quick method. Under general conditions, medical units may switch to whole-body anesthesia or apply muscle relaxants; smaller medical units might switch to other local anesthetics or intravenous anesthesia, using muscle relaxants during surgery. This not only complicates procedures but also increases the economic burden on patients. Group 1 applied tetracaine concentration without achieving satisfactory results. To address this issue, inspired by subarachnoid block, tetracaine was used at concentrations ranging from 0.1% to 0.5%. Observations were made at 0.4%, 0.45%, 0.5%, 0.6% tetracaine (with each concentration having 3-5 cases), yet hair follicle effects were still not ideal, showing incomplete muscle relaxation. The latter two concentrations did not exhibit any toxic reactions or complications (in fact, 0.6% proved better than 0.5%, acting faster and improving muscle relaxation, though it was not dared to be routinely applied without basis). Routine application of these concentrations yielded satisfactory results in handling this phenomenon. From the results, it can be seen that the lidocaine resistance phenomenon occurred clinically more meaningfully after repeated applications, especially after the initial dose, which is particularly significant for inexperienced young doctors who often mistakenly believe this is due to inaccurate puncture or catheter placement outside the dura mater leading to imperfect blocks, thus causing misunderstanding among surgeons. Its incidence is very low, with this group having nearly 18 years of clinical epidural anesthesia experience involving over 2,000 cases of lidocaine, where only more than 12 cases exhibited such resistance phenomena. Timely determination of resistance phenomena is crucial for simple, fast, and safe correction. The occurrence of tachyphylaxis is interpreted as follows: in Group A, after injection of the commonly used concentration, there was no absorption of lidocaine liquid, which was diluted to reduce its effective role, even if diluted - times the lower half of the concentration remains within the effective range, since limited experimental capacity prevented further investigation.