Postmortem redistribution (PMR) refers to the postmortem processes that change drug distribution and concentration in tissues. This results in drug blood concentration variation depending on the site where the blood is sampled. It is also influenced by the elapsed post-mortem interval at the time of sampling. This complex phenomenon is still not entirely understood but authors generally agree on three main factors, i.e. passive drug diffusion from reservoir organs where drugs accumulated antemortem, cellular acidification and autolysis leading to disruption of the protein binding characteristics of substances in tissues, and the pharmacokinetic properties of drugs. While almost all drugs exhibit some degree of PMR, it is almost impossible to predict the extent to which a substance will redistribute after death.
In other words, postmortem redistribution leads to blood drug concentration variation after death depending on many factors, which include sampling site, the technique used for the sampling and postmortem interval.
A search of the literature shows that the popliteal vein has never been reported as a sampling site nor compared with other sampling sites, e.g., cardiac, subclavian and femoral sites.
This study looked at the practical value of sampling in the popliteal region, the technical problems and how the postmortem interval affected drug blood concentrations.
The study was the first to evaluate concurrently three main aspects of PMR for three selected drugs as well as their metabolites, and indicated that popliteal vein may represent a better postmortem blood sampling site.