Brady M D, Hustead R R, Robinson R H, Becker K E
Department of Anesthesiology, University of Kansas School of Medicine-Wichita 67214.
Reg Anesth. 1994 May-Jun;19(3):196-8.
Proparacaine (P), 0.5%, is often applied topically to the eye to diminish the pain of injection of anesthetic for eye surgery; however, application of 0.5% P itself can cause some degree of discomfort. This study evaluated the use of balanced salt solution to dilute P before instillation in the eye to prevent discomfort.
In a double-blinded manner, 42 consenting adults about to undergo cataract surgery were given 0.5% P in one eye and 0.03% P in the other eye. One minute later the same solutions were instilled into each eye. Ten minutes later, 0.5% P was instilled into both eyes. After each instillation the patients were asked to describe the pain in each eye on a 0 to 10 scale.
Those receiving 0.5% as the first drop had a mean pain score of 1.28, which was greater than the score of 0.09 for the 0.03% P group (P < .01). No one reported pain after the second drop was applied 1 minute later. After receiving 0.5% P 10 minutes later, the group that had received 0.5% P reported a mean pain score of 0.09 while those who had received 0.03% P reported a score of 0.76, which was significantly greater than that reported by the 0.5% P group after the 10 minute instillation (P < .01) but significantly lower than the score reported after the first instillation of 0.5% P (P < .05).
Dilution of P in balanced salt solution to a concentration of 0.03% produces a solution that is significantly less painful than 0.5% P and reduces the discomfort of the instillation of 0.5% P.
0.5%的丙美卡因（P）常用于眼部局部给药，以减轻眼科手术麻醉注射时的疼痛；然而，0.5%的丙美卡因本身的应用也会引起一定程度的不适。本研究评估了在滴眼之前使用平衡盐溶液稀释丙美卡因以预防不适的效果。
以双盲方式，为42名即将接受白内障手术的成年受试者一只眼滴入0.5%的丙美卡因，另一只眼滴入0.03%的丙美卡因。一分钟后，将相同溶液分别滴入每只眼睛。十分钟后，两只眼睛均滴入0.5%的丙美卡因。每次滴入后，要求患者用0至10分的量表描述每只眼睛的疼痛程度。
首次滴入0.5%丙美卡因的患者平均疼痛评分为1.28分，高于0.03%丙美卡因组的0.09分（P <.01）。一分钟后滴入第二滴溶液后，无人报告疼痛。十分钟后滴入0.5%丙美卡因后，接受过0.5%丙美卡因的组平均疼痛评分为0.09分，而接受过0.03%丙美卡因的组评分为0.76分，该评分显著高于10分钟滴入0.5%丙美卡因组报告的评分（P <.01），但显著低于首次滴入0.5%丙美卡因后报告的评分（P <.05）。
将丙美卡因用平衡盐溶液稀释至0.03%的浓度后，其产生的溶液疼痛程度明显低于0.5%的丙美卡因，并减轻了滴入0.5%丙美卡因时的不适。
