Appropriate use of local anaesthetic for venous cannulation

Abstract

SummaryA departmental survey indicated that the large majority of anaesthetists believed that injection of local anaesthetic before insertion of an intravenous cannula was unnecessary i f a cannula of 18 gauge or smaller was used, because injection of local anaesthetic would be more painful than insertion of the cannula. A study was undertaken to test this hypothesis. The results showed that intravenous cannulation with a cannula of 18. 20 or 22 gauge was signiJicantly ( p < 0.006) more painful than a subcutaneous injection of I% lignocaine. We recommend that subcutaneous injection of local anaesthetic should be considered before insertion of any size of intravenous cannula. Key wordsVeins; cannulation. Anaesthetics, local; lignocaine.It is common practice amongst anaesthetists to inject subcutaneous lignocaine 1% before insertion of a large intravenous cannula in adults. However, a survey in our anaesthetic department revealed that there was no unanimous opinion as to the smallest size for which the pain of insertion of a cannula was outweighed by the pain caused by the prior injection of local anaesthetic. Eighty-eight per cent of anaesthetists in our department used local anaesthetic before inserting a cannula of 16 gauge or larger, but only a small proportion used local anaesthetic before insertion of a cannula of 18 gauge or smaller in adults. The principal reason given for this practice was that insertion of a small cannula is not painful, and that the pain of injecting local anaesthetic exceeds the pain of insertion of the cannula.Consequently, a study was undertaken to assess the validity of this opinion, and to establish which size of intravenous cannula, in the opinion of the patient, warranted the prior subcutaneous injection of subcutaneous lignocaine 1 YO. Patients and methodsThe study was approved by the District Ethics Committee and written informed consent was obtained from all participants. Sixty adult patients, who were about to undergo surgery under general anaesthesia, were included in the trial. Each patient was allocated randomly into one of three groups, to receive intravenous cannulation with a Venflon cannula of 18 (group I), 20 (group 2) or 22 gauge (group 3). Random allocation was achieved by taking a prewritten card, blind, from a bag, such that 20 patients entered each group. Within each group, the side of cannulation (left or right) and the order of cannulation (before or after subcutaneous injection of lignocaine) was randomised equally within groups by the same method. Patients were premedicated or not as determined by the anaesthetist.The patient's eyes were closed throughout the procedure and a tourniquet was applied to both arms. A subcutaneous injection of 0.25 ml of lignocaine 1% through a 25 gauge needle was given into the dorsum of one hand and a Venflon of predetermined size was inserted into the corresponding site in the other hand (or vice versa depending on randomisation).

The use of pre-cannulation local anaesthetic and factors affecting pain perception in the emergency department setting

“…4 5 8 SC lignocaine injection has been shown to be less painful than insertion of 18, 20 and 22 gauge cannulas. 6 Post-cannulation insertion site pain may be abolished by the use of local anaesthetic (LA). 5 Despite the evidence favouring the use of LA, many clinicians fail to do so, 7 believing the pain of cannulation to be minimal or not worth the time and expense of LA.…”

Evaluation of a needle‐free injection system for local anaesthesia prior to venous cannulation

“…An effective alternative is to inject a local anaesthetic, such as lidocaine, intradermally or subcutaneously at the site of proposed cannulation [5]. Although this local anaesthetic injection has been demonstrated to cause less pain than the cannulation itself, even for 22G cannulae, it is usually associated with a degree of discomfort or pain [6].…”

Efficacy of the jet injector in local anaesthesia for small wound sutures: a randomised clinical trial compared with the needle infiltration technique

“…However, for many patients, delivery of local anaesthetic agents via needle infiltration provokes anxiety or discomfort 2 4 9 10. Also, administration of intradermal or subcutaneous lidocaine through needle injection is not easily applicable in some groups of patients, especially the paediatric population 8 10 11…”

“…It has been used as a tool for administration of heparin, midazolam, ketamine and intradermal anesthetics 14. The safety, efficacy and costs of jet injection for local anaesthesia before performing intravenous catheterisation, fine needle aspiration biopsy for palpable breast mass, male vasectomy and dentistry procedures has recently been studied 3–4 6 9 11. However, there is a paucity of knowledge regarding the efficacy of the jet injector in local delivery of lidocaine for suturing skin wounds.…”