Possible postmortem serum markers for differentiation between fresh-, saltwater drowning and acute cardiac death: a preliminary investigation.

The aim of the present study was to investigate the differences in postmortem blood biochemistry between fresh-, saltwater drowning and acute myocardial infarction/ischemia (AMI) (n=11, n=15 and n=23, respectively; postmortem interval <48 h). Left and right cardiac blood samples were examined for the serum markers: sodium (Na), chloride (Cl), magnesium (Mg), blood urea nitrogen (BUN), creatinine (Cr), pulmonary surfactant-associated protein A (SP-A) and cardiac troponin T (cTn-T). The most efficient markers were the left-right cardiac BUN ratio for determination of drowning (hemodilution) and the left heart blood Mg level for differentiation between fresh- and saltwater aspiration. A characteristic feature of saltwater drowning was a low left-right BUN ratio and a marked elevation in the serum Cl, Mg and Ca levels of the left heart blood. Serum cTn-T level was usually low in drownings, showing a difference from most cases of AMI. Freshwater drowning showed a significant elevation of serum SP-A, although there was considerable overlapping with saltwater drowning and AMI. These findings suggested the usefulness of serum markers in the investigation of death from drownings.