Vitreous Potassium Concentration Research Articles

Estimation of Time Since Death by Potassium ion Level in the Vitreous Fluids: A Postmoterm Study in a Tertiary Care Center, South India

Background: It is of great value to find time since death in the medicolegal investigations like serious crimes.Vitreous humor was more often used for the biochemical analysis as it is less contaminated or not affected by the putrefactive changes than other fluids of the body. It was stated by many researchers that potassium levels in the vitreous humour is more accurate in predicting time since death.Aim: The aim of the study is to assess the time since death using potassium level in the vitreous humorMethodology: This study includes 54 cases of victims brought to the tertiary care hospital based on inclusion and exclusion criteria. Cases with known time of death and with clear vitreous humor samples were included. Baseline characteristics like name, age, gender, exact time since death was collected. Vitreoushumor was collected through appropriate standardized technique. Sampling time was also noted. The collected data was entered in MS excel and analysis done in SPSS 23 software. P value <0.05 is considered to be significant.Results: Majority of the study participants belongs to 57-67 years of age group (28%) followed by 27-37 years of age (22%).Male predominance was observed in our study 41(76%). There is a linear correlation found between the vitreous potassium concentration and the postmortem interval (R2=0.907). The rate of the vitreous potassium increase was 0.36 meq/hr (Coefficient of regression =2.76 meq/l/hr)Conclusion: There is a linear relationship found between vitreous potassium concentration and time since death.Thus potassium in the vitreous can be used for assessing the time since death.

Estimation of Time Since Death From Potassium Levels in Vitreous Humor in Cases of Unnatural Death: A Facility-Based Cross-Sectional Study.

Background Estimation of time since death/postmortem interval (PMI) forms a crucial component for all autopsy surgeons. With the subjectivity that is prevalent with conventional morphological and physical signs of death, newer-age modalities such as chemical analysis providebetter precision. The easy accessibility and the resistance to putrefactionmakevitreous humor the best choice for such chemical analysis. Thus, the present study's aim is to estimate the time since death in cases of unnatural death by investigating the potassium level changes in the vitreous humor. Methodology This is a facility-based cross-sectional study conducted in the mortuary under the Department of Forensic Medicine in a public tertiary healthcare teaching hospital in South India between August and September 2022. Deceased individuals fulfilling the inclusion and exclusion criteria were recruited in the study. Vitreous samples were collected from a single eye and analyzed using an autoanalyzer for potassium values. After due derivations, postmortem intervals were calculated from potassium values, then they were compared with the PMIs estimated using physical signs and those determined using official police records. Data were entered using MS Excel 20 (Microsoft Corporation, Redmond, Washington) and analyzed using the Statistical Package for the Social Sciences (SPSS) software, version 20 (IBM Corp., Armonk, NY). Results Of the 100 deceased individuals included in the study, 68%were men, and the majority (24%) belonged to the age group of 53-62 years. A linear relationship is said to exist between vitreous potassium concentration and postmortem interval. No correlation was seen between the ambient temperature and the potassium levels of the vitreous humor. PMI confirmed by the potassium levelsseconded the PMI given by the police records andphysical signs (Rigor mortis) (Spearman's rho was statistically significant at the two-tailed level or at the 0.01 level with a kappa value of 0.88). Conclusion Potassium measurements in the vitreous humor to estimate the PMI are associated with improved accuracy and precision in determining the time since death. They are not affected by external factors, makingthem a reliable marker for the same.

Estimation of post-mortem interval from vitreous potassium: An autopsy based study

Time since death which is the interval between death and the time of post-mortem examination is important during investigation of a crime. It is also called as ‘post-mortem interval’ (PMI). A repeated problem in Forensic Medicine is the inability to fix the time when death occurred within the limits of probability. It is self-evident that more the duration between death and the examination of the body, longer will be the limits of probability. In this study, time since death was determined from potassium level in the vitreous humor and a formula was derived for the Chennai region. A prospective interventional study was conducted taking 75 vitreous samples. Potassium estimation was done using a fully automated analyzer- Siemens ADVIA1800. During the studied post-mortem period, a consistent liner rise of vitreous potassium was seen. The mean range of vitreous potassium concentration in the subjects varied between 5.4 mmol/L to 36.00 mmol/L (Mean ± SD, 19.30 ± 6.64). In the present study the average rate of increase of vitreous potassium was calculated as 0.931 mmol/L per hours with 95% confidence limit over ± 20 hours. The potassium-based formula derived from the present study to estimate PMI is: PMI = 1.075 (K+ mmol/L) – 2.53. The coefficient of correlation between postmortem interval and potassium concentration was found to be 0.997 in the present study, in comparison with studies done by Sturner & Gantner(1963). Vitreous potassium level linearly increase with time since death and can be used as a reliable parameter.

Vitreous potassium concentration as a predictor of postmortem interval in severe burn deaths at Alexandreia mortuary

ABSTRACT Background: Postmortem interval (PMI) estimation is an important goal in forensic medicine. After death, many physiochemical changes occur in a regular sequence and thanatochemistry is the chemistry of death. They can be used to arrive at an approximate time of death. Aim: to estimate the time since death using a scoring method for three postmortem changes; hypostasis, rigidity and corneal turbidity in sever burn cases. Also, to evaluate the use of thanatochemistry; potassium (K+) in vitreous humor (VH) and serum in determination of (PMI) and compare the accuracy of thanatochemistry and the scoring method for postmortem changes in estimation of PMI. Methods: The study was conducted on 100 adult autopsy cases of known postmortem interval presented to the mortuary of Alexandria from May 2017 to May 2018, 50 burn cases where autopsy confirmed the cause of death as severe burns and another 50 control cases. The development of postmortem rigidity, hypostasis and corneal turbidity was assessed and numerically scored. The potassium (K+) levels in vitreous humor (VH) and serum were measured. The data were statistically analyzed and linear regression analysis was used to obtain equations for calculation of PMI .Results: All the studied variables in the present study were significantly correlated with PMI; highest correlation coefficient in control and burn groups was for K+ level in VH, followed by corneal turbidity and serum K+ then rigidity in burn groups, but in control groups the highest correlation coefficient was for K+ level in VH and serum, followed by rigidity then corneal turbidity and lastly hypostasis. All equations obtained from the present study can predict PMI but with different levels of accuracy. Conclusion: The most accurate equation in control cases was that concerning with all the five studied variables. Furthermore, the scoring method for the physical postmortem changes was proved to be more valuable in PMI estimation than thanatochemistry. No much difference between accuracy of equations in burn cases was that concerning with all the five studied variables.

Role of Vitreous Humor in Estimating Time Since Death

Background: Estimation of time since death is important for the investigation of crime. This study was done on about 200 medico legal autopsies at KIMS Hospital Bangalore. The information regarding time of death was gathered from hospital records. The data was collected and recorded on proforma and subjected to statistical analysis. Results: The ratio of male and female cases was 1.739:1. Around 42% were in the age group of 21-30 years. Majority of cases were from trauma (43%). The overall range of time since death was 0 to 72 hrs. The overall range of vitreous potassium ion concentration was 3.1 to 24 meq/L and maximum number of cases were in range between 6.1 to 12 meq/l (72%) followed by 3.1 to 6 meq/l (25%). Conclusion: In our present study, we have noticed linear rise of vitreous potassium concentration upto 57 hrs and positive correlation between vitreous potassium concentration and post-mortem interval.

Prospective Anaylysis of Electrolytic Changes in Vitreous Humour Regarding Estimation of Time Since Death

Prospective Anaylysis of Electrolytic Changes in Vitreous Humour Regarding Estimation of Time Since Death

Vitreous potassium concentration as a predictor of postmortem interval: A cross-sectional study among natural death cases at a tertiary care center in rural Haryana

Background: Time since death (TSD) is an important parameter to the forensic expert. Only a few studies are available in the literature to determine the relationship between the vitreous potassium (K + ) concentration and TSD especially among natural death cases in the state of Haryana and, thus, information on the same is patchy and scanty. Objective: To determine the relationship between changes in the vitreous K + concentration and increasing TSD among natural death cases. An additional objective was to derive a formula for determining TSD from changes in levels of vitreous K + in the study subjects. Materials and Methods: In this study, autopsy cases brought to the mortuary of the Department of Forensic Medicine and Toxicology of a tertiary care center, were the subjects for collection of vitreous humor for the determination of vitreous K + . Data of 90 such cases where autopsy confirmed the cause of death as natural death were included in this study. Determination of K + level in the collected sample was done by ion-selective electrode method (Biolyte 2000 autoanalyzer, Biocare, Lujhu Township, Taiwan). Results: A linear relationship was observed between vitreous K + concentration and TSD in both the eyes. External factors like seasonal variations and temperature, gender difference, and age had no appreciable effect on the concentration of vitreous K + in either eye. In this study, the linear regression equations obtained from K + concentration (y) versus time (x) for the two groups among injury (trauma) cases were as follows: For the right eye: Regression line (y) = -4.303 x + 2.148 and for the left eye: Regression line (y) = -5.260 x + 2.209. The K + levels are found to increase up to 40 h after death. Conclusion: The study highlighted the usefulness of the relationship between vitreous K + concentration and TSD in both the eyes. The formula calculated from the current study could prove to be more appropriate as it is based on a more recent study and more reliable tests.

Medicolegal study of determination of time since death from potassium level in vitreous humour

Background: From the knowledge of science, various workers have established the methods of determining post mortem interval by the use of physical changes after death. Unfortunately the accuracy was low and margin of error high as evident from the literature available. Trends are now shifting towards the use of various chemical methods like estimation of electrolyte concentration of cerebrospinal fluid, synovial fluid and vitreous humour. Vitreous humour is stable, less contaminated by putrefaction, easily accessible in sufficient quantity. Thus, it is suitable to determine time since death. Methods: The present cross-sectional study was carried out in grant Govt. medical college; Mumbai on 200 cases brought to the mortuary from the period 1st January 2011 to 31st May 2013. Results: It was found that there was linear correlationship between vitreous humour potassium concentration and increasing post-mortem interval irrespective of age, sex, temperature, humidity and mode of death. Conclusions: There was linear relationship between vitreous potassium concentration and post-mortem interval. The accuracy of prediction of PMI can be improved by applying present study formula. The rate of rise of potassium level in vitreous humour was 0.23mEq/L/hr No significant difference in vitreous potassium concentration between the two eyes was noted when samples were drawn at the same PMI. There was no significant effect of age, sex, temperature, humidity and mode of death on vitreous potassium level after death.

Vitreous potassium concentration as a predictor of postmortem interval in injury (trauma) cases: A cross-sectional study from a tertiary care center in rural Haryana

Background: Time since death (TSD) is an important parameter to the forensic expert. Only a fewer studies are available in the literature to determine the relationship between vitreous K + concentration and TSD especially among injury (trauma) cases and thus information on the same is patchy and scanty. Objective: To determine the relationship between changes in vitreous K + concentration with increasing TSD among injury (trauma) cases. An additional objective was to derive a formula for determining TSD from changes in levels of vitreous K + in the study subjects. Materials and Methods: In this study, autopsy cases brought to the mortuary of Department of Forensic Medicine and Toxicology of a tertiary care center, were the subjected for collection of vitreous humor for determination of vitreous potassium. Data of 55 such cases where autopsy confirmed the cause of death as injury (trauma), were included in this study. Determination of potassium level in the collected sample was done using ion-selective electrode method (Biolyte 2000 auto analyzer). Results: A linear relationship was observed between vitreous potassium concentration and TSD in both the eyes. External factors like seasonal variations and temperature, gender difference and age had no appreciable effect on the concentration of vitreous potassium in either eye. In this study, the linear regression equations obtained from potassium concentration (y) verses time (x) for the two groups among injury (trauma) cases were as follows: For right eye: Regression line (y) = −5.040 (x) = +1.989, for left eye: Regression line (y) = −5.223 (x) = +2.005. The potassium levels are found to increase up to 40 h after death. Conclusion: The study highlighted the usefulness of relationship between vitreous potassium concentration and TSD in both the eyes. The formula calculated from the current study could prove to be more appropriate as it is based on a more recent study and more reliable tests.

Vitreous potassium concentration as a predictor of postmortem interval: A cross-sectional study among poisoning and burns cases at a tertiary care center in rural Haryana

Background: Time since death (TSD) is an important parameter to the forensic expert. Only a few studies are available in the literature to determine the relationship between vitreous K + concentration and TSD, especially among poisoning and burns cases, and thus information on the same is scant. Therefore the present study was planned. Objective: The main objective was to determine the relationship between changes in vitreous K + concentration with increasing TSD among poisoning and burns cases. An additional objective was to derive a formula for determining TSD from changes in levels of vitreous K + in the study subjects. Materials and Methods: In this study, autopsy cases brought to the mortuary of the Department of Forensic Medicine and Toxicology of a tertiary care center were subjected to collection of vitreous humor for the determination of vitreous K + . Data of 36 cases where autopsy confirmed the cause of death as poisoning or burns were included in this study. Determination of K + level in the collected samples was done by the ion-selective electrode method (Biolyte 2000 autoanalyzer). Results: A linear relationship was observed between vitreous K + concentration and TSD in both the eyes. External factors such as seasonal variations and temperature, gender difference, and age had no appreciable effect on the concentration of vitreous K + in either eye. In this study the linear regression equations obtained from potassium concentration (y) versus time (x) for the two groups among poisoning and burns cases were as follows. For right eye: Regression line (y) = -4.932 x + 1.932; for left eye: Regression line (y) = -5.380 x + 1.990. The K + levels were found to increase up to 40 h after death. Conclusion: This study highlighted the usefulness of the relationship between vitreous potassium concentration and TSD in both the eyes. The formula calculated from the current study could prove to be more appropriate as it is based on more reliable tests.

Can Vitreous Potassium Concentration Predict Postmortem Interval in Cases of Poisoning and Burns? A Cross Sectional Study from a Medical School

Background: Estimation of time elapsed after death remains one of the most important requirements in medico legal autopsies. Time since death (TSD) provides a clue to the investigating officer to institute suitable inquiries to apprehend the person likely to be responsible for crime and to eliminate the innocent ones. Aim: Aim of the current study was to analyze and ascertain the relationship between vitreous K+ concentration and TSD among poisoning and burn cases. We also aimed to derive a formula for determining TSD from changes in levels of vitreous K + concentration. Methods: The present cross sectional study was carried out among the autopsy cases brought to the mortuary of Department of Forensic Medicine and Toxicology of a medical school for the post mortem examination. All the autopsy cases were entailed the collection of vitreous humour for determination of vitreous potassium. Data of all those autopsy cases was analyzed in which cause of death was either poisoning or burns. Potassium levels were quantified in the collected sample by the ion-selective electrode method. Regression and correlation analysis were performed. Results: Data of 72 study subjects belonging to poisoning and burn cases were analyzed. The mean vitreous

Vitreous Humor: Biochemical Constituents in Estimation of Postmortem Interval*,†

Analysis of biochemical constituents of the vitreous humor can be useful in determining the postmortem interval as there is proportionate postmortem rise of potassium and fall in sodium concentration. We studied 120 autopsy cases to determine the utility of potassium, sodium, calcium, and chloride levels, and sodium/potassium ratio in estimating the postmortem interval. There was a linear relationship between vitreous potassium concentration and postmortem interval, whereas an inverse relationship between vitreous sodium/potassium ratio and postmortem interval was noted. Other factors like age, sex, cause of death, season of death, and refrigeration of sample did not influence the vitreous humor potassium values. Using the statistical tools, a new formula was derived to determine the postmortem interval based on the potassium concentration and a review of previous literature is presented. Hence, the findings of this study supported a central role of vitreous humor biochemistry in many postmortem forensic and pathological evaluations.

Vitreous humor analysis for selected biochemical parameters from cervids in Idaho.

Vitreous humor and liver samples were collected from hunter-harvested elk (Cervus elaphus) and mule deer (Odocoileus hemionus) in Idaho (USA). Concentrations of calcium, chloride, potassium, sodium, urea nitrogen and selenium were determined and evaluated according to species, age, gender, geographic location, and time elapsed following death. Vitreous humor analysis yielded reliable biochemical information for < or = 96 hr subsequent to the death of the animal. Vitreous potassium concentration changes over time could be used to estimate the time that elapsed following death.

Intraocular fluid dynamics. Measurements following vitrectomy and intraocular sulfur hexafluoride administration.

Partial vitrectomies were performed in rabbits, replacing 40% of initial vitreous volume with 100% sulfur hexafluoride, and concentrations of sodium, potassium, calcium, magnesium, ascorbate, and protein were determined in aqueous and vitreous at 10, 14, 21, 28, 56, and 110 days. There were significant increases of potassium, calcium, magnesium, and protein above control values at varying times throughout the study. Vitreous potassium concentration was decreased at 14 and 21 days. All other measurements were similar to control values. Results of studies indicate that, following vitrectomy in rabbits, the blood-retinal barrier can re-form in 14 days and blood-aqueous barrier in ten days. However, a greater than normal exchange diffusion of these measured substances occurs between aqueous and vitreous through 21 days. Four eyes with cataracts, vitreous membranes, and/or detached retinas demonstrated elevated aqueous and vitreous protein concentrations through 110 days, although other measurements returned to normal levels.