Ursell P G, Spalton D J
Department of Opthalmology, St. Thomas' Hospital, London, England.
Ophthalmology. 1996 May;103(5):839-41. doi: 10.1016/s0161-6420(96)30606-4.
Peribulbar anesthesia is the preferred technique of local anesthesia of the majority of cataract surgeons. Local anesthetic injections at other sites in the body have been shown to be less painful if the solution is warmed to body temperature before injection. To determine whether this is of advantage with peribulbar anesthesia, the authors performed a prospective, randomized, single, blind trial comparing local anesthetic injections that have been warmed to room temperature.
Forty consecutive patients undergoing routine cataract surgery were randomized into two groups of 20 patients and received local anesthetic at 20 degrees C or 37 degrees C. The peribulbar injection contained a solution of 5 ml 2% Lignocaine, 5 ml 0.5% bupivicaine (Marcaine), and 1550 IU hyaluronidase (HYlase) in a 10-ml syringe on a 25-mm, 25-gauge needle. Seven milliliters of the final solution was injected transcutaneously at the junction of the lateral and medial thirds of the lower lid. The patients graded the pain of the injection using a visual analogue scale.
The pain sensation of local anesthesia is less when the solution is warmed to body temperature compared with room temperature (P = 0.026, using an unpaired Student's t test).
Warming the local anesthetic used in peribulbar anesthesia to body temperature before injection reduces this iatrogenic pain significantly.
球周麻醉是大多数白内障手术医生首选的局部麻醉技术。研究表明，在身体其他部位注射局部麻醉剂时，如果在注射前将溶液加热至体温，疼痛会减轻。为了确定球周麻醉是否也有此优势，作者进行了一项前瞻性、随机、单盲试验，比较了加热至室温的局部麻醉剂注射情况。
40例接受常规白内障手术的连续患者被随机分为两组，每组20例，分别接受20℃或37℃的局部麻醉剂。球周注射采用10毫升注射器，25毫米、25号针头，溶液包含5毫升2%利多卡因、5毫升0.5%布比卡因（耐乐品）和1550国际单位透明质酸酶（玻璃糖醛酸酶）。将7毫升最终溶液经皮注射在下睑中外1/3交界处。患者使用视觉模拟量表对注射疼痛进行评分。
与室温相比，将溶液加热至体温时局部麻醉的疼痛感较轻（使用不成对学生t检验，P = 0.026）。
球周麻醉前将局部麻醉剂加热至体温可显著减轻这种医源性疼痛。
