Arendt-Nielsen L, Bjerring P
Department of Medical Informatics, Aalborg University, Denmark.
Acta Anaesthesiol Scand. 1989 Aug;33(6):469-73. doi: 10.1111/j.1399-6576.1989.tb02947.x.
The cold and warmth thresholds to thermode stimulation and the sensory and pain thresholds to argon laser stimulation were determined before and after topical application of EMLA (Eutectic Mixture of Local Anaesthetics) cream. The sensory threshold to argon laser stimulation and warmth threshold to thermode stimulation are both described in terms of warmth or faint heat. The sensory threshold persisted for more than 80 min of EMLA application, whereas the warmth and cold thresholds were detectable after 105 min in half the volunteers. Pain evoked by strong laser pulses was abolished after 80 min of cream application. The analgetic effect of topically applied lidocaine/prilocaine, evaluated by the cutaneous thermal and pain threshold, is compatible with the idea that topical application of EMLA cream blocks free nerve endings rather than the nerve fibres, and induces a sequence of sensory loss which, in some respects, differs from that typically observed after perineural application of local anaesthetics. The effect of topically applied anaesthetics is influenced by a number of thermodynamical, anatomical, and physiological factors in the skin.
在局部应用EMLA（局部麻醉剂的共熔混合物）乳膏前后，测定了对热刺激的冷、热阈值以及对氩激光刺激的感觉和疼痛阈值。对氩激光刺激的感觉阈值和对热刺激的热阈值均以温热或微热来描述。在应用EMLA后，感觉阈值持续超过80分钟，而在一半的志愿者中，105分钟后可检测到热阈值和冷阈值。在应用乳膏80分钟后，强激光脉冲引起的疼痛消失。通过皮肤热阈值和疼痛阈值评估，局部应用利多卡因/丙胺卡因的镇痛效果符合以下观点：局部应用EMLA乳膏阻断的是游离神经末梢而非神经纤维，并引发一系列感觉丧失，在某些方面，这与局部应用局部麻醉剂后通常观察到的情况不同。局部应用麻醉剂的效果受皮肤中多种热力学、解剖学和生理学因素的影响。
