SummaryA recent study performed in this department showed that a subcutaneous injection of local anaesthetic was significantly less painful than the insertion of a 22-gauge venous cannula. However, our colleagues remained sceptical that local anaesthetic infltration would eliminate the pain of cannulation. Consequently a further study was undertaken to compare the pain of cannulation with and without the use of local anaesthetic. The results show that pain of cannulation is significantly ( p < 0.003) reduced after subcutaneous infltration with I % lignocaine when compared to cannulation without local infltration. Persistent discomfort at the site of cannulation was eliminated by the use of local anaesthetic. Key wordsVeins; cannulation. Anaesthetics, local; lignocaine.A survey undertaken in this department revealed that most anaesthetists did not employ infiltration of local anaesthetic before insertion of an 18, 20 or 22-gauge intravenous cannula because they believed that cannulation was less painful than injection of lignocaine. We demonstrated [I] that intravenous cannulation with a cannula of 18,20 or 22 gauge was significantly (p < 0.006) more painful than a subcutaneous injection of 1 % lignocaine. These results were disseminated within our anaesthetic department, but most anaesthetists remained of the opinion that the combination of local anaesthetic infiltration and insertion of an intravenous cannula (which had not been investigated) was more painful than cannulation alone.This study was undertaken to establish whether prior injection of local anaesthetic significantly diminishes the pain of cannula insertion when using a small intravenous cannula (1 8-22-gauge). 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 or regional anaesthesia, were included in the trial. Patients were allocated randomly (sealed envelope technique) 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). Within each group, the side of local anaesthetic infiltration was randomised equally between left and right. 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 lignocaine I % through a 25-gauge needle was given into the dorsum of one hand and 1 min later a Venflon of predetermined size was inserted into the vein through the site of local infiltration. A Venflon of the same size was inserted into the corresponding site in the other hand. Cannulation was performed in the left hand first in all patients.The patients were then asked which procedure was the more painful and graded each insertion on a discrete pain scale of 1 to 10 ( I : no pain; 10: worst pain imaginable). All cannulations were successful at the first attempt. After a delay of ...

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).

We have compared the cardiovascular response to insertion of an 18-gauge venous cannula in 40 healthy patients. In 20 of the patients, cannulation was preceded by infiltration of local anaesthetic. Both rate-pressure product and mean arterial pressure increased significantly (P < 0.01) compared with baseline when no local infiltration was used, but there was no significant change from baseline when infiltration with local anaesthetic preceded cannulation. We conclude that there is a significant pressor response to venous cannulation which is obtunded by prior infiltration with local anaesthetic. We recommend, therefore, that s.c. injection of lignocaine should be considered before insertion of an i.v. cannula, especially in the high risk patient.

We present a case of abdominal aortic aneurysm repair using a new technique of aortic stenting and discuss the anaesthetic technique used and the perioperative advantages of the technique.