Comparison of Pain of an Intramuscular Injection of Bupivacaine with Different Diluting Solutions

Chung, Jin Yong; Song, Seok Young; Kim, Bong Il; Roh, Woon Seok; Cho, Soung Kyung

Abstract

BACKGROUND: Although used for obtund pain, bupivacaine may itself initially produce pain on injection. This study was designed to evaluate the effect of diluting bupivacaine with normal saline, lactated Ringer's solution, 5% dextrous in water and distilled water on perception of pain associated with intramuscular injection.
METHODS
Twenty-five healthy volunteers were involved in this study. Each subject received 4 injections in random order: 0.25% bupivacaine in normal saline, lactated Ringer's solution, 5% dextrous in water and distilled water. Both upper trapezius muscles were used for the intramuscular injection site. Needle size (25-gauge), injection depth (1.5-2 cm), injection volume (2.5 ml), administration speed (0.5 ml/sec), and temperature (room) were controlled for each of the four injections. The intensity of pain was rated on a 0 to 10 visual analogue scale (VAS) score at the point of needle insertion and injecting solutions.
RESULTS
There was no statistical difference among each solution in VAS score. However, the VAS scores of drug administration were higher than those of needle insertion in all diluting solutions (P<0.05).
CONCLUSIONS
There was no difference in the intensity of pain of an intramuscular injection of bupivacaine between four different kinds of solutions. However, it might be suggested that more effort and investigation will be needed to reduce pain with an intramuscular injection.