Clivia Guerrero-Urbina; Martha Fors; Mariano del Sol & Gabriel M. Fonseca

The postmortem interval (PMI) is an important challenge to be solved in forensic pathology, and it consists of being able to determine the time elapsed from death to the moment of autopsy. Given the unreliability of some methods due to the great influence of external factors and those specific to the corpse, forensic biochemistry has received considerable attention for its levels of safety. The city of Quito is located in the Andes mountain range at 2850 meters above sea level, however, in the literature there are no reports of measurement of these parameters at a height like this. The objective was to establish a correlation between sodium (Na+), chlorine (Cl-) and potassium (K+) of the vitreous humor and the MPI at a height of 2,850 masl. For the study, 128 samples of vitreous humor were used from 16 autopsies performed in the Zone 9 Legal Medicine Unit, in IPM of 6, 12, 24, 48, 72, 96, 120 and 144 hours. To obtain the vitreous humor, the conventional method was followed, it was divided for the 8 aliquots and it was frozen at -20 ° C until the moment of its analysis. The quantification of the concentration of electrolytes Na+, Cl- and K+ was carried out using an ISE analyzer from Roche Cobas (Roche Diagnostics) C501, calibrated for urinalysis, and no dilution was necessary. During calibration and every third sample, an internal standard was measured to correct for the effects of systematic deviation on the calibration. The statistical approach was based on a linear correlation analysis, using the Spearman correlation coefficient. The correlation between the postmortem hours and the concentrations of the different electrolytes were statistically significant. A significant linear correlation between the PMI and the increase in K+ in vitreous humor could be corroborated.

GUERRERO-URBINA, C.; FORS, M.; DEL SOL, M. & FONSECA, G. M.Correlation between sodium, chlorine and potassium of the vitreous body and the postmortem interval above 2,850 masl. Int. J. Morphol., 39 (2):554-559, 2021.