Evaporated Liquid Nitrogen-Induced Asphyxia: A Case Report

A 27-yr-old postgraduate student was found lying at the floor of an unsealed underground dry area, where a valve-opened empty cylinder of liquid nitrogen (150 L) was connected to a cap-removed empty Dewar-flask (10 L) via a copper infusion tube. No injury was found externally or internally. There were petechiae in the bilateral conjunctivae and periorbital skin. The dry area, measuring 300X130X260 cm, had a communication to the basement of the research building by a window measuring 90X60 cm in size at 130 cm above the floor. The scene reconstruction and atmosphere gas analysis revealed that the O2 concentration at 60 cm above the base dropped to 12.0% in 3 min and 10 sec, 10.0% in 8 min and 53 sec, 6.0% in 18 min and 40 sec, and 4.2% in 20 min and 28 sec. The primary cause of death was asphyxia by evaporated liquid nitrogen..

Induction of hypoxia-inducible factor-1alpha in two kinds of rats asphyxiation death models / 法医学杂志

OBJECTIVE@#To investigate the expression of hypoxia-inducible factor 1-alpha (HIF1-alpha) in the heart, lung, liver and kidney in rats died of two typical models of asphyxia.@*METHODS@#Two asphyxia models were made and tissue samples of the dead rats were collected from different groups at various postmortem duration. The expression and the changes of HIF1-alpha in various tissues were examined by immunohistochemistry and image analysis techniques. Results Significant expression of HIF1-alpha was observed in the myocardial fibers, kidney cells, liver cells and lung cells in both asphyxia models, but not in the control group. The expression of HIF1-alpha in various tissues in the rat died of nitrogen gas breathing was found in the nuclei at 0 hour and the expression level decreased gradually thereafter. The HIF1-alpha expression level and duration in various tissues of the rat died of hanging were higher and longer than that of the former group, with a peak of the expression level observed 6 hours after death, and then started to decline in all tissues except the heart where the expression still showed an increase 24 hours after death. The control groups showed a steady expression in the cytoplasm but not in the nuclei.@*CONCLUSION@#HIF1-alpha appears to be a valuable biomarker in the diagnosis of asphyxia within 24 hours after death.