Elevations in postmortem vitreous sodium chloride (PMVSC) levels may help in differentiating saltwater/seawater drowning (SWD) deaths from immersion deaths not related to drowning (DNRD). It is unclear whether the elevation is related to blood/plasma electrolyte changes after inhalation of seawater as hypothesized in SWDs or possibly caused by electrolyte diffusion and/or osmosis across the outer coats of the eyeball during immersion.Aim
To investigate the changes in bovine PMVSC levels at different time points while immersed in seawater.Methods
Bovine eyeballs were obtained from an abattoir and randomized into 2 groups: a) submerged in seawater (“wet” group) or b) placed in an impermeable plastic bag that was immersed in seawater (“dry” group). The PMVSC levels from 6 eyeballs were measured from each group (without replacement) at 30 minutes, 1 hour, 6 hours, and 12 hours.Results
There was no significant difference in mean PMVSC levels between the 2 groups at 30-minute and 1-hour intervals. A significant difference was noted from 6 hours onward.Discussion
There is no statistically significant elevation in bovine PMVSC levels when immersed in seawater for up to 1 hour. Assuming similar physical properties in humans, any elevations in PMVSC levels in bodies immersed in seawater for less than 1 hour should not be caused by immersion.