Changes in plasma catecholamine concentrations following infiltration with large volumes of local anaesthetic solution containing adrenaline.

Plasma catecholamine concentrations have been measured in nine patients undergoing rhinoplasty following infiltration to the facial area of 21 ml of 0.5% lignocaine with adrenaline 1:200,000 and in seven patients undergoing brachial plexus blockade with 40 ml of 0.5% lignocaine, 0.25% bupivacaine and adrenaline 1:200,000. In the rhinoplasty group there was a 566% increase in plasma adrenaline concentration 2 min after cessation of infiltration, whilst in the brachial plexus group a 112% increase in the plasma concentration of adrenaline occurred at 10 min after completion of the block. There was no change in plasma noradrenaline concentration in either group. It is concluded that the so-called safe dose of adrenaline (1.0 microgram kg-1 during halothane anaesthesia) is meaningless unless the site of administration is specified.