The effects of drowning media on the lung water content. An experimental study on rats.

Three kinds of drowning media, i.e., fresh water, isotonic saline, and hypertonic saline were used. After a rat was placed in a desiccator, measuring 17 cm in height and 14 cm in diameter, the vessel was filled with fluid. The average survival time of about 2.5 min did not differ significantly among the three groups. The hypertonic saline group showed the highest values in both the water content of the lung and the lung/body weight ratio; however, this group did not differ significantly from the isotonic saline group in either of the parameters. The difference between the isotonic saline group and the fresh water group was significant. There was a significant positive correlation between the two parameters. However, the lung/body weight ratio was more sensitive to the nature of the drowning media. The frequency, with which froth appeared at the nostrils of the animals that were recovered from the fluid differed significantly among the three groups. The froth appeared almost exclusively in the rats drowned in saline solution. The appearance rate seemed to depend on the salinity of the fluid. There was no significant difference in lactate concentrations among the three groups. The electrolyte (Na and Cl) concentrations in the blood of the right side of the heart reflected the composition of the drowning media.