title: EMLA and water immersion cause similar vasodilatation in replanted fingers.
abstract: BACKGROUND
  Skin wrinkling on water immersion is a reliable and simple test of sympathetic innervation. The eutectic mixture of local anesthetic (EMLA) cream has been shown to induce near identical clinical wrinkling scores and reduction in digit blood flow as that following water immersion in people with normal sympathetic innervation. This study was designed to investigate the vasomotor response to EMLA in replanted fingers that had poor sympathetic innervation.
  
  
  METHODS
  Laser Doppler imaging (PeriScan PIM II; Perimed AB, Stockholm, Sweden) was used to detect perfusion changes in the pulps of fourteen replanted fingers before and after 0.5 g of 5% EMLA cream application and water immersion in a 40 degrees C normal saline for 30 min, respectively. Comparisons were made with the contralateral corresponding normal fingers.
  
  
  RESULTS
  After water immersion and EMLA application, all of the normal fingers showed a considerable and similar decrease in blood perfusion that demonstrated in the absolute perfusion units (pU) (baseline: 1.57 +/- 0.33 pU, after water-immersion, 1.19 +/- 0.22 pU, P < 0.001; decrease: 23.6 +/- 7.7%, after EMLA application: 1.20 +/- 0.18 pU, P < 0.001; decrease: 22.4 +/- 8.9%). In contrast, all of the replanted fingers showed a statistically significant vasodilatatory response (baseline: 1.20 +/- 0.29 pU, after water-immersion: 1.36 +/- 0.28 pU, P < 0.001; increase: 15.2 +/- 9.1%, after EMLA application: 1.38 +/- 0.27 pU, P < 0.001; increase: 16.8 +/- 9.1%).
  
  
  CONCLUSIONS
  EMLA and water immersion both cause vasodilatation and no skin wrinkling in replanted fingers. These results imply that intact sympathetic nerve function is required to induce the vasoconstrictive effect of EMLA.
authors: Department of Neurosurgery, Chang Gung Memorial Hospital--Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Hsien, Taiwan.
authors: Ching-Hua
authors: CH
authors: Hsieh
authors: Kuo-Feng
authors: KF
authors: Huang
authors: Po-Chou
authors: PC
authors: Liliang
authors: Pei-Chi
authors: PC
authors: Huang
authors: Hsin-Miao
authors: HM
authors: Shih
authors: Cheng-Shyuan
authors: CS
authors: Rau
mesh_terms: D000328:Adult; D000779:Anesthetics, Local / Q000008:administration & dosage*; D005260:Female; D005383:Finger Injuries / Q000601:surgery*; D005385:Fingers / Q000098:blood supply / Q000294:innervation / Q000601:surgery; D006801:Humans; D007101:Immersion; D017078:Laser-Doppler Flowmetry; D008012:Lidocaine / Q000008:administration & dosage*; D000077442:Lidocaine, Prilocaine Drug Combination; D008297:Male; D008875:Middle Aged; D011318:Prilocaine / Q000008:administration & dosage*; D012039:Regional Blood Flow / Q000187:drug effects; D012092:Replantation; D012881:Skin Temperature / Q000187:drug effects; D012965:Sodium Chloride; D013564:Sympathetic Nervous System / Q000502:physiology; D014664:Vasodilation / Q000187:drug effects*; D014867:Water
chemical_list: D000779:Anesthetics, Local; D000077442:Lidocaine, Prilocaine Drug Combination; D011318:Prilocaine; D014867:Water; D012965:Sodium Chloride; D008012:Lidocaine