Post Mortem analysis of electrolytes in vitreous humour to determine time since death
Keywords:iron selective electrode, vitreous humour electrolyte, autopsy, Maharashtra
Background: It has been found that so many biochemical materials, including electrolytes, remain remarkably
stable after death while others show varying degrees of change; hence, the analysis of electrolytes in vitreous
humour has great medico-legal importance.
Method: 95 autopsies were studied by making a puncture 5–6 mm away from the limbus by using a 10 ml sterile
syringe and 20 gauze needles. Aspirated vitreous was poured into a rubber stopped vial. The collected fluid was
sent to the biochemistry department for electrolyte analysis. The analysis was carried out using the iron selective
electrode method, and the results were noted and compared.
Results: The PM interval for 27 cases (28.4%) was < 12 hours, 32 cases (33.6%) was between 12-24 hours, and
36 cases (37.8%) was >24 hours. In the study of different electrolytes, the sodium chloride value remained
insignificant, but the potassium value had a highly significant p value (p<0.001). The highest mean value of
potassium 10.62 (±1.90) in accidental falls and least in snake bite deaths was 6.7 (±0.23).
Conclusion: The present pragmatic study has proved that vitreous potassium is the single best parameter to
estimate and predict post mortem death accurately.