EMLA Registered Trademark Cream for Venipuncture in Patients with Reflex Sympathetic Dystrophy

Abstract

To the Editor: The review article by Gajraj et al. [1] and the letter by Nerad et al. [2] underline the widespread clinical use of eutectic mixture of local anesthetics (EMLA Registered Trademark cream; Astra Pharmaceutical Products Inc., Westborough, MA). In addition to the uses pointed out, our experience has shown that the application of EMLA Registered Trademark cream can be a very useful measure to facilitate venipuncture in patients with reflex sympathetic dystrophy (RSD; Sudeck's atrophy). Intravenous regional blocks with guanethidine are a safe and effective treatment in these patients. Venous cannulation, however, can be a very painful procedure due to the fact that most patients with RSD experience hyperalgesia and allodynia. Because edema is a major symptom, venipuncture in the affected limb can often be very difficult. After a first unsuccessful attempt, patients will frequently not allow any further manipulation of the affected limb due to pain and frustration. Furthermore, there is also a pathophysiologic reason to avoid painful procedures such as venipuncture in patients with RSD. Any nociceptive input can contribute to central sensitization, a mechanism instrumental in the development of chronic pain syndromes [3]. Additional pain can result in increased activity of the sympathetic efferents with deterioration of the symptoms. With the use of EMLA Registered Trademark cream, venipuncture for intravenous blocks is no longer a distressing procedure. The confidence in painless venous cannulation decreases the patients' fears and encourages them to continue with a series of blocks. From the pathophysiologic point of view, painless venipuncture with EMLA Registered Trademark cream prevents iatrogenic nociceptive impulses. This might help to achieve better results with sympatholytic blocks. We did not perform a prospective, randomized, double-blind study regarding the use of EMLA Registered Trademark cream in patients with RSD because we considered it to be unethical in this particular patient population. However, based on our experience, we strongly recommend the application of EMLA Registered Trademark cream before venipuncture for intravenous blocks in patients with RSD. Norbert Grie beta inger, MD Reinhard Sittl, MD Department of Anesthesiology, University of Erlangen-Nurnberg, 91054 Erlangen, Germany