Document resource
We read with interest the study by Istenič et al,1 which provides quantitative data on bupivacaine distribution using high-performance liquid chromatography coupled with mass spectometry (HPLC-MS) in cadaveric tissue. The authors should be commended for addressing an important limitation of experimental models of interfascial plane blocks. Their second hypothesis, that bupivacaine permeates fascial layers to a greater extent than hydrophilic visual tracers, is supported by the presented data.