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Interpretation of COHb concentrations in the left and right heart blood of cadavers
T Miyazaki1, T Kojima, M Yashiki
1Department of Legal Medicine, Hiroshima University School of Medicine, Japan.
Insights
Analyzing carbon monoxide hemoglobin (COHb) in cadaver blood samples reveals the left/right heart ratio is generally unhelpful for determining fire exposure timing. Exceptions exist for cases without soot and normal COHb levels.
Area of Science:
- Forensic Toxicology
- Pathology
- Analytical Chemistry
Background:
- Carbon monoxide (CO) poisoning is a significant cause of accidental and intentional deaths.
- Determining the timing of CO exposure relative to death is crucial in forensic investigations.
- Carbon monoxide hemoglobin (COHb) levels in blood are key indicators of CO exposure.
Purpose of the Study:
- To evaluate the utility of the carbon monoxide hemoglobin (COHb) concentration ratio between left and right heart blood samples.
- To determine if this ratio can reliably indicate whether death occurred before or after exposure to fire or CO gas.
Main Methods:
- Gas chromatographic analysis was employed to measure COHb concentrations.
- Blood samples were collected from the left and right heart of cadavers.
- Cadavers were categorized based on exposure to fire or CO gas and presence of soot.
Main Results:
- The COHb concentration ratio between left and right heart blood (L/R ratio) was generally not useful for determining the timing of death relative to fire exposure.
- A potential exception was noted in cases with no visible soot in the airways and COHb levels within the normal range for smokers.
Conclusions:
- The L/R COHb ratio is not a reliable standalone indicator for post-mortem fire exposure assessment.
- Further investigation is needed for specific scenarios, particularly those lacking soot and exhibiting borderline COHb levels.
Abstract:
Carbon monoxide hemoglobin (COHb) concentrations in left and right heart blood samples from cadavers both exposed and not exposed to fire or CO gas were analyzed by the gas chromatographic method. The COHb concentration ratio between samples of left and right heart blood (L/R ratio) does not appear to be useful for establishing whether death has occurred before or after exposure to fire with the exception of cases where no soot can be detected in the airways by the naked eye and the COHb concentration in the blood sample is within the level considered normal for tobacco smokers.