Lack of concentration-dependent local toxicity of highly concentrated (5%) versus conventional 0.5% bupivacaine following musculoskeletal surgery in a rat model.

Purpose: Various sustained-release formulations incorporate high bupivacaine concentrations but data on local toxicity is lacking. This study explores local toxic effects of highly concentrated (5%) bupivacaine compared to clinically used concentrations in vivo following skeletal surgery, to assess the safety of sustained-release formulations with high bupivacaine concentrations.

Methods: Sixteen rats underwent surgery, in which screws with catheters affixed were implanted in the spine or femur in a factorial experimental design, allowing single-shot or continuous 72 h local administration of 0.

Effects of recruitment strategies and demographic factors on inclusion in a large scale vaccination trial in adults 65 years and older.

Large-scale randomized studies generate the highest level evidence for medical interventions. Yet, successful recruitment frequently is challenging, especially when targeting elderly populations. Although several studies investigated specific recruitment barriers, there is little quantitative understanding of such barriers.