ABSTRACT
In a double blind study, using supraclavicular plexus blockade as a model, the latency and diffusion of carticaine in comparison with mepivacain was investigated. Up to 16 min after first eliciting paraesthesiae and injection somewhat more plexus blocks were complete with carticain than with mepivacaine. This difference was statistically valid only for motor block and not for sensory block. However, the relative proportion of complete motor and sensory block increased with mepivacain after 16 min and surpassed the results for carticaine. This difference is statistically significant for sensory block and for sensory and motor block combined. It is also valid for the results up to 30 min. The failure rate was significantly higher for carticaine than for mepivacaine. From these results the course and the failures are attributed to a poorer diffusion of carticaine.