On the distubance of gas exchange in the lung in SIDS.Pathological and ultrastructural observation.

对28例SIDS（2个月~ 1.5岁）、12例窒息（1天~ 64岁）和6例溺水（4个月~ 9岁）患儿进行组织学观察，发现所有SIDS患儿均有肺水肿，部分SIDS患儿肺水肿较窒息和溺水严重。但是，由于表现出严重肺水肿的SIDS病例在医院接受了输血，因此不能得出SIDS病例中肺水肿的严重程度显著高于窒息或溺水的结论。研究了由血小板、纤维蛋白和/或白色血细胞组成的微栓子的发生，认为这是窒息的特征性发现。通过观察200倍计数每30个显微镜视野的微栓子数量来确定微栓子的发生。SIDS、窒息和溺水患者每30个微栓子平均数分别为5.67 <plus-minus>± 6.65、5.78 ± <plus-minus>3.42和4.8 <plus-minus>± 1.77。将SIDS病例分为两组：急性胃内容物或乳汁吸入肺的病例和无急性吸入的病例。急性误吸组的平均微栓子数为9.86 ± <plus-minus>7.85。未吸痰组为2.02 ± 1.00。对5例SIDS进行了超微结构观察，均见肺泡壁水肿。为了测量肺泡壁水肿的严重程度并明确肺泡壁水肿是否干扰气体交换，使用3例SIDS病例（3个月至6个月）显示轻度死后变化，并使用1例头部外伤病例（1个月和3个月）作为对照，测量肺泡上皮细胞表面与内皮细胞表面的组织屏障厚度。SIDS病例的组织屏障厚度分别为0.61、0.62和0.65 μ m，而对照病例为0.63 μ m。

Histological observation was performed using 28 cases of SIDS (2 months to one and a half years old) , 12 cases of asphyxia ( 1 day to 64 years old) and 6 cases of drowning (4 months to 9 years old) .All SIDS cases showed pulmonary edema and some SIDS cases showed more severe pulmonary edema, compared with that of cases of asphyxia and drowning. But, because SIDS cases showing severe pulmonary edema had received transfusion in hospitals, it was not concluded that severity of pulmonary edema in SIDS cases was significantly higher than that of asphyxia or drowning. Occurrence of microemboli which were composed of plateletes, fibrin and/or white blood cells, and considered as a characteristic finding in asphyxia, were investigated. Occurrence of microemboli was determined by counting of a number of microemboli per 30 microscopic fields by obseving 200 folds. The average numbers of microemboli per 30 microscopic fields in SIDS, asphyxia and drowning were 5.67<plus-minus>6.65,5.78<plus-minus>3.42 and 4.8<plus-minus>1.77, respectivly. SIDS cases were divided into 2 groups ; cases showing acute aspiration of gastric content or milk into the lung and cases without acute aspiration. The average number of microemboli in the group with acute aspiration was 9.86<plus-minus>7.85. On the other hand, that of the group without aspiration was 2.02<plus-mUltrastructural observation was performed using 5 cases of SIDS.Edema in the alveolar walls was observed in all cases. In order to measure severity of edema in the alveolar walls and make it clear if edema in the alveolar wall disturbs gas exchange, thickness of tissue barrier from the surface of the alveolar epithelium from that of endothelial cells, using 3 SIDS cases (3 months to 6 manths old) showing mild postmortem changes and one case of head trauma (one and 3 months old) as a control. The thickness of tissue barrier in SIDS cases were 0.61,0.62, and 0.65 mum, respectively and in the control case was 0.63mum.