Zhu B.^*, Quan L.^*, Ishida K.^*, Oritani S.^*, Imura M.^*, Fujita M.Q.^*, Maeda H.^*, Ogawa M.^**, Tanaka N.^***, Komura S.^****, Tsuji T.^*****

^*Department of Legal Medicine and ^**Hospital Department of Pharmacy, Osaka City; University Medical School, Asahi-machi 1-4-54, Abeno, 545 Osaka, Japan
^*** Department of Forensic Medicine, School of Medicine, University of Occupational and Environmental Health, 807 Kika-Kyushu, Japan
^****Department of Legal Medicine, Kyoto Prefectural University of Medicine, 602 Kyoto, Japan
^*****Department of Legal Medicine, Wakayama Medical College, 640 Wakayama, Japan

We investigated forensic pathological significance of pulmonary surfactant in interpretation of respiratory failure or distress for the fatal mechanisms in poisoning.
Materials and Methods. Distribution of surfactant apoprotein A was immunohistochemically investigated using autopsy materials of fatalities due to various kinds of poisons (total 22 cases) including muscle relaxants, anesthetics, sedative-hypnotics, carbon monoxide, petroleum gas, and ethanol.
Results and Discussion. Surfactant apoprotein A was most intensely observed in poisoning with pancuronium bromide (muscle relaxant) and in fatalities from inhalation of petroleum (butane) gas. In poisoning with sedative-hypnotics, the increase of surfactant was not so evident. Carbon monoxide poisoning showed various distributions from case to case. Among the pulmonary micromorphological findings (congestion, edema and hemorrhages), the alveolar septal (interstitial) edema seemed to have been most closely related to the increase of surfactant. The above-described observations indicated that pulmonary surfactant (apoprotein A) may be a possible indicator of respiratory distress (asphyxiation) of peripheral origins (agony) and the agonal periods.
Conclusions. In this study, it was suggested that the intensity of pulmonary surfactant (apoprotein A) immunostaining may be most closely related to the duration of respiratory distress (agony).