[Local digital anesthesia using lidocaine with or without bicarbonate. A comparative randomized study].
OBJECTIVE
Local anesthesia with lidocaine is widely used in surgery of the extremities, particularly for fingers. Injection causes pain. In order to minimize this discomfort, addition of bicarbonate has been used by many authors. Results were however contradictory in relation with the difference of approaches. Our study is based on a randomized comparative series with and without lidocaine alcalinization.


METHODS
Sixty patients presenting multidigital trauma concerning at least two fingers. For each patient, one finger was anesthetized by lidocaine 2 per cent alone and one by lidocaine 2 per cent plus bicarbonate 8.4 per cent respectively in proportion of 4/5 and 1/5. We compared the intensity of pain during injection by a scale ranging from 0 to 10.


RESULTS
Significant difference was found between both groups (p < 0.001), alcalinization appearing to decrease discomfort during injection.


CONCLUSIONS
Mechanism of pain decrease by alcalinization is unclear. It appears that intracellular passage of non ionic form of lidocaine is facilitated by alcalinization. This allows the decrease of latence of lidocaine and relieve pain more rapidly by pain receptors blockade.


CONCLUSIONS
Diminution of pain during anesthetic injection has major advantage in out-patient surgery of extremities, in ligamentar testing of digital articulations and in steroid injection.
Fikry
T
T
Service de chirurgie orthopédique et réparatrice, CHU Ibnou Rochd, Casablanca, Maroc.
al Harrar
R
R
Harfaoui
A
A
Harti
A
A
Zryouil
B
B
D000328:Adult; D000468:Alkalies; D000556:Ambulatory Surgical Procedures; D000772:Anesthesia, Local / Q000009:adverse effects; D000779:Anesthetics, Local / Q000008:administration & dosage* / Q000009:adverse effects / Q000493:pharmacokinetics; D001639:Bicarbonates / Q000008:administration & dosage* / Q000009:adverse effects / Q000493:pharmacokinetics; D002021:Buffers; D005383:Finger Injuries / Q000601:surgery; D005385:Fingers / Q000601:surgery*; D006801:Humans; D007267:Injections / Q000009:adverse effects; D008012:Lidocaine / Q000008:administration & dosage* / Q000009:adverse effects / Q000493:pharmacokinetics; D008297:Male; D009619:Nociceptors / Q000187:drug effects; D010146:Pain / Q000209:etiology; D010147:Pain Measurement; D011446:Prospective Studies; D011930:Reaction Time
D000468:Alkalies; D000779:Anesthetics, Local; D001639:Bicarbonates; D002021:Buffers; D008012:Lidocaine