Subcutaneous Single Injection Digital Block with Epinephrine

The aim of this study was to investigate the anesthetic effect and risk of epinephrine for subcutaneous single injection digital block. Either 3.0？mL 1.0% Lidocaine or a 3.0？mL 1.0% Lidocaine with (1？:？100,000) epinephrine was injected into the subcutaneous space at the middle point of the palmar digital crease of the 18 middle fingers of 9 healthy volunteers. The SpO2 of the fingers decreased to a maximum of 97. No subjects showed any symptoms of ischemic injury. The time to anesthesia for the fingers was significantly shorter ( ), and the duration of anesthesia was significantly longer ( ) for the fingers in the epinephrine group. In conclusion, a subcutaneous single injection digital blocks with 3.0？mL of 1.0% Lidocaine and (1？:？100,000) epinephrine were safe, reducing the time to the onset of anesthesia, while also markedly prolonging the anesthesia. 1. Introduction Many specialists feel that local anesthesia with epinephrine should not be used for a digital block. Epinephrine is a strong alpha- and beta-receptor agonist and, therefore, results in the activation of alpha-receptors in digital arteries leading to vasoconstriction. The digital arteries are terminal or end arterioles, and this vasoconstriction can lead to ischemia and gangrene [1]. However, a careful review of the literature from 1880 to 2000 revealed that there were only 48 case reports of digital gangrene and necrosis following local anesthesia in the digits, and most of those were published before 1950 [2]. In addition, those cases of digital gangrene were associated with procaine and cocaine injection with or without epinephrine. Necrosis has never been reported in patients treated with a commercial lidocaine-epinephrine mixture. Early reports in the second half of the 20th century support the safety of lidocaine with epinephrine in digital anesthesia. Three studies reported no complications after performing digital blocks using local anesthetics with epinephrine in 93 and 98 patients, respectively [3, 4]. However, the digital block techniques in those reports were classical digital blocks, using the so-called Oberst procedure. This technique requires at least two injections. Various protocols for single injection digital block have been reported since 1990 [5–8]. In particular, a subcutaneous single injection digital block is simple procedure [8]. The purpose of this study was to investigate the anesthetic effect and risk of epinephrine for subcutaneous single injection digital block. 2. Materials and Methods This study was enrolled on 9 normal, healthy volunteers, who were junior