Ordog G J, Ordog C
UCLA Medical Center, Los Angeles, California, USA.
Acad Emerg Med. 1994 Jul-Aug;1(4):360-3. doi: 10.1111/j.1553-2712.1994.tb02644.x.
To associate the efficacy of topical anesthesia of a tetracaine-adrenaline-cocaine solution (TAC) with the duration of skin contact.
A prospective, physician-blinded, observational study of anesthetic efficacy as a function of TAC application duration in pediatric patients (age range 1-12 years) who had superficial lacerations was performed. Patients who had lacerations less than 5 cm long were eligible for the study. Patients who had lacerations of the finger, toe, penis, nose, or pinna were excluded. Patients with histories of allergies to any of the topical anesthetic components also were excluded. Nursing staff measured the duration of TAC application (always > 5 min). Effectiveness of anesthesia was rated by the single treating physician blinded to TAC application duration.
For the 400 patients enrolled in the study, TAC provided better anesthesia when the wound-application duration was more than 20 minutes (p = 0.0001). This commonly was evidenced by complete blanching of the skin within 1 cm of the wound's edges. The percentage of patients having good anesthesia at 5-10 minutes was 62% (95% CI = 46-76%) versus 97% (95% CI = 93-99%) at 31-40 minutes. No side effect was observed in any group.
TAC is most effective as a topical anesthetic when applied for more than 20 minutes prior to suturing.
将丁卡因 - 肾上腺素 - 可卡因溶液（TAC）局部麻醉的效果与皮肤接触时间相关联。
对患有浅表撕裂伤的儿科患者（年龄范围1 - 12岁）进行了一项前瞻性、医生盲法观察研究，以探讨麻醉效果与TAC应用时间的关系。撕裂伤长度小于5 cm的患者符合研究条件。手指、脚趾、阴茎、鼻子或耳廓有撕裂伤的患者被排除。对任何局部麻醉成分有过敏史的患者也被排除。护理人员测量TAC的应用时间（始终>5分钟）。由对TAC应用时间不知情的单一主治医生对麻醉效果进行评级。
对于纳入研究的400名患者，当伤口应用时间超过20分钟时，TAC提供了更好的麻醉效果（p = 0.0001）。这通常表现为伤口边缘1 cm内的皮肤完全变白。5 - 10分钟时麻醉效果良好的患者百分比为62%（95%CI = 46 - 76%），而在31 - 40分钟时为97%（95%CI = 93 - 99%）。任何组均未观察到副作用。
在缝合前应用超过20分钟时，TAC作为局部麻醉剂最为有效。
