Elevated postmortem vitreous sodium and chloride levels distinguish saltwater drowning (SWD) deaths from immersion deaths not related to drowning but recovered from saltwater (DNRD)

Abstract

A 5-year prospective study of saltwater-related deaths was undertaken in 2 medico-legal centers in Australia. This demonstrated a statistically significant elevation (P<0.01) in postmortem vitreous sodium and chloride (PMVSC) levels and sum of sodium and chloride levels in 15 cases of deaths due to saltwater drowning (SWD) in comparison with 7 immersion deaths not related to drowning but recovered from saltwater (DNRD), and with 50 case controls. From our data, PMVSC was superior to using sodium or chloride levels alone in discriminating SWD from DNRD and controls. It is proposed that in cases where bodies are retrieved from a saltwater environment and SWD is suspected, a PMVSC of 284 mmol/L or higher is consistent with SWD. Conversely, a PMVSC level of less than 258 mmol/L is inconsistent with SWD. A PMVSC between 258 and 284 mmol/L is inconclusive or noninformative, and circumstantial evidence and autopsy findings are needed to determine the cause of death. It is suggested that PMVSC measurement is a worthwhile test in determining the cause of death in cases where bodies are recovered from saltwater, especially in cases where an internal examination of the body may not be authorized or where objections to autopsy are upheld.