The lung swap method is a method to search intact plankton microscopically in the lung fluid to diagnose the drowning death. In order to evaluate the efficacy of this method in differentiating the drowning from the non-drowning cases, as many as 49 cases of drowning and 25 cases of non-drowning death were examined. Among the drowning group, 91.8% (45 out of 49 cases) had planktons in the lung fluid, consisted of algae (diatom and non-diatom) and non-alga planktons. The other 4 cases had no plankton in their lung fluid, as 3 of them were drowned in the pool and the other one in a bathtub; both kinds of places contained relatively clean water which is suspected plankton-free. Among the non-drowning group, only 4% (1 out of 25 cases) was plankton positive, having 3 different species of non-diatom algae in the lung fluid, while the other cases showed no plankton at all. Statistically, using the Fischer test, the two groups showed a significant difference (p less than 0.001, risk ratio 22.96 and odd’s ratio 270.00). The composition of the planktons is usually mixed and showed either diatom or non-diatom alga domination. The non-alga plankton was rarely found in this study. Among the drowners, 14.4% (7 out of 49 cases) showed only non-diatom plankton in the lung fluid. In these cases the Acid Destruction method, which was the usual method for diagnosing drowning death using strong and concentrated acids, would give false negative results, because the acids would destroy the lung tissue and the non-diatom plankton. This means that in these cases, the lung swab method is superior than the acid destruction method.
- Acid destruction method
- Lung swap method