Article Sidebar
Article Details
Issue
Section
Articles
By submitting manuscripts to SAJAA, authors of original articles are assigning copyright to the SA Society of Anaesthesiologists. Authors may use their own work after publication without written permission, provided they acknowledge the original source. Individuals and academic institutions may freely copy and distribute articles published in SAJAA for educational and research purposes without obtaining permission.
Main Article Content
Alkalinisation does not enhance the antimicrobial properties of local anaesthetic solutions
Abstract
Background: The purpose of the study was to examine the previously reported finding that the addition of bicarbonate to lignocaine enhanced the antimicrobial effect of the local anaesthetic agent on a range of bacteria implicated in epidural infections and to determine if this would also hold true for bupivacaine.
Methods: Bupivacaine at a concentration of 0.25% and lignocaine at a concentration of 1% with and without an alkaline buffer were inoculated with suspensions of Staphylococcus epidermidis, Staphylococcus aureus or Escherichia coli. The mixtures were plated on 2% blood agar plates immediately (T = 0) and after 24 hours at room temperature (T = 24), and numbers of colonies were recorded. The difference in the number of colonies between T = 0 and T = 24 was expressed as a fraction of the T=0 value, giving a percentage inhibition of colony growth. Statistical testing was performed using Kruskal-Wallis non-parametric One Way Analysis of Variance (ANOVA) followed by multiple comparisons of mean ranks between all groups.
Results: At concentrations of 0.25% bupivacaine and 1% lignocaine, these findings suggest that 1% lignocaine has no antibacterial activity. The addition of bicarbonate has no influence.
Conclusions: Bupivacaine has significant antibacterial activity, but the addition of bicarbonate has no influence.
Methods: Bupivacaine at a concentration of 0.25% and lignocaine at a concentration of 1% with and without an alkaline buffer were inoculated with suspensions of Staphylococcus epidermidis, Staphylococcus aureus or Escherichia coli. The mixtures were plated on 2% blood agar plates immediately (T = 0) and after 24 hours at room temperature (T = 24), and numbers of colonies were recorded. The difference in the number of colonies between T = 0 and T = 24 was expressed as a fraction of the T=0 value, giving a percentage inhibition of colony growth. Statistical testing was performed using Kruskal-Wallis non-parametric One Way Analysis of Variance (ANOVA) followed by multiple comparisons of mean ranks between all groups.
Results: At concentrations of 0.25% bupivacaine and 1% lignocaine, these findings suggest that 1% lignocaine has no antibacterial activity. The addition of bicarbonate has no influence.
Conclusions: Bupivacaine has significant antibacterial activity, but the addition of bicarbonate has no influence.
