Spectrophotometric evaluation of postmortem lividity.

Area of Science:

• Forensic Science
• Toxicology
• Biophysics

Background:

• Postmortem lividity typically appears bluish but can be pinkish under certain conditions.
• Pink hypostasis (postmortem lividity) presents a diagnostic challenge, with carbon monoxide poisoning being a key differential diagnosis alongside cold exposure.

Purpose of the Study:

• To determine if objective spectrophotometric measurements can differentiate pink postmortem lividity caused by cold exposure from that caused by carbon monoxide poisoning.

Main Methods:

• Spectrophotometric measurements were used to determine colorimetric values (CIE-L*a*b*) and spectral reflectance curves of postmortem lividity.
• Analysis focused on differentiating patterns associated with cold exposure versus carbon monoxide (CO) intoxication.

Main Results:

• Colorimetric measures (CIE-L*a*b*) were similar for all bright red livores mortis, making differentiation difficult.
• Spectral reflectance curves for cold-exposed lividity showed typical O2-rich blood patterns (minima at 541 nm & 576 nm, maximum at 560 nm).
• Pink lividity from CO poisoning showed a reflectance maximum shift toward 555 nm and a flattened curve, particularly with COHb concentrations over 52%.

Conclusions:

• Spectrophotometry, specifically analyzing spectral reflectance curves, can differentiate pink postmortem lividity due to cold exposure from that caused by carbon monoxide poisoning.
• The observed spectral shifts and curve flattening in CO poisoning cases provide objective criteria for diagnosis.