The blood lancet in regional anaesthesia.

Sir,—The success of regional anaesthesia depends upon accurate placement of local anaesthetic solution in the proximity of nerve trunks [1] without causing sequelae such as neural lesions and damage to blood vessels, tendons, muscles or pleura [2-6]. The classic methods of locating nerves used the production of paraesthesiae with the standard bevel needle. New techniques have been developed which use neurostimulation [7, 8] and atraumatic bevelled needles [9] of the "short bevel" and "pencil point" type. Neurostimulation as a method of locating the neural plexus requires the use of needles insulated along their entire length except for the point [10, 11]. This offers a more favourable geometry to the zone of depolarization [12]. The use of the short bevel or pencil point needle was promoted by Whitacre in 1951 [13] and more recently by Selander [14] and Galindo [9, 15]; a number of retrospective studies have directly related the incidence of nerve lesions to the technique used and the bevel of the needle [3, 4]. However, there may be difficulty in introducing a relatively blunt needle through the skin of the patient, and the insulation may act as a brake, thereby impeding smooth passage. We have been able to overcome this problem by making a small incision with a surgical blade after a subcutaneous infiltration with local anaesthetic. Alternatively, the blood lancet may be used. Because of its configuration it breaks only the epidermis and the dermis and creates the appropriate orifice for the atraumatic introduction of 20-25 gauge needles.