Evaluation of eye and blood findings in di̇fferent waters in rabbits by drowning and immersion modeling

In corpses removed from the water, a diagnosis of drowning can be made after excluding other causes of death apart from drowning. Several factors such as death without witnesses, prolonged immersion, or decay can make a forensic specialist have a difficulty in determining exact cause of death. Post-mortem changes may negatively affect decision process on potential cause and time of death, by impairing integrity of body. Therefore, further contemporary tests which can evaluate the origin of death of corpses removed from the water objectively and reproducibly, using different perspectives are needed. This experimental study aim to analyse the biochemical parameters that have a potential in determining the origin of death in the corpses removed from the water by collecting eye and blood samples from the corpses removed from the water. In this study, the groups were divided into five groups: control group, saltwater drowning, saltwater immersion, freshwater drowning, and freshwater immersion. Blood samples were collected from each group at the end of 0, 2, and 4 hours, and the colorimetric method was used for the Mg measurement with the Otto Scientific OttoBC151 device, and the ISE method was used for the Na and Cl measurement with the Siemens device. On post-mortem examination, vitreous and humour aqueous samples were taken using a injector at the fourth hour. Furthermore, Pentacam measurements were done to all subjects at 0, 2, and 4 hours. The obtained data were analysed using SPSS software. Descriptive statistics were presented with frequency, percentage, mean, median, and standard deviations. The parametric parameters were compared using the One-Way ANOVA test and post hoc comparisons were performed using the Tukey test. Homogeneity of variances was evaluated with Levene's test. Nonparametric parameters were compared using Kruskal-Wallis test. Pairwise comparisons were done using the Mann-Whitney U test. When it comes to the outcomes of this study, there was a significant difference between the 2nd-hour blood sodium levels of the saltwater immersion group and the saltwater drowning group. Na levels can be considered to provide valuable information in the diagnosis of early drowning in corpses coming out of the water. The data obtained from the study showed that stand-alone blood chlorine levels were unbeneficial in diagnosis of drowning. When comparing the changes in blood chlorine and magnesium levels over time, a significant difference was observed between the two groups. Serum chlorine and magnesium levels are considered to be indicator for revealing whether the corpse was removed from fresh or saltwater as they varied depending on the removal of corpse either from fresh or saltwater. Magnesium levels in vitreous samples taken at the 4th hour were found similar among the experimental groups. This supports that stand-alone post-mortem vitreous magnesium levels are unbeneficial in diagnosing drowning in prolonged immersion. The outcomes obtained in the study, similar to the data from literature, indicates that vitreous electrolytes are meaningless in long-term immersion in water. Statistically significant differences were found between the groups in aqueous sodium, chlorine and magnesium levels taken at the 4th hour, thus suggesting that aqueous Na, Cl, and Mg levels can be useful in diagnosing drowning of corpses staying in the water, especially in saltwater, for up to 4 hours. In all rabbits, corneal thickness, corneal volume, anterior chamber volume, and anterior chamber depth were evaluated with Pentacam Topography. Although corneal thickness and corneal volume differed significantly among the groups at baseline, no significant difference was observed at 2 and 4 hours. However, when evaluating the changes in corneal thickness and corneal volume over time, there was a significant difference among the groups. This can be explained by the fact that corneal thickness and volume increase over time in freshwater cases while they decrease in saltwater cases. Corneal thickness and volume cannot be considered to be used alone in diagnosing drowning; however, they can provide valuable information for differentiating drowning in fresh water from drowning in saltwater. There was no significant difference in anterior chamber volume at 0, 2, and 4 hours. However, we determined the decrease in the change over time within all groups. Although there was no significant difference between the groups in anterior chamber depth at baseline, a significant difference was found at the 2nd and 4th hours. When examining the change of anterior chamber depth over time, we observed a significant difference among the groups, which tended to decrease over time. Considering that anterior chamber volume and anterior chamber depth are unbeneficial in the diagnosis of drowning, but decrease gradually over time in all groups, these two parameters can be valuable in predicting death time. This experimental study demonstrated that corneal thickness, corneal volume, anterior chamber volume, and anterior chamber depth were useless in the differential diagnosis of drowning, and were affected by the fresh or salty nature of the water rather than drowning type. The findings showed that anterior chamber fluid could provide valuable information for differentiating freshwater drowning from saltwater drownings at 4 hours in corpses staying in the water. Aqueous Na and Cl levels, especially in corpses removed from saltwater, seem to be useful test that can easily differentiate the possible causes of drowning. Our results are encouraging; however, further large-scale studies with autopsy series are still needed.