VITAL TESTS

VITAL TESTS have essential significance for resolving the question of the live birth of a fetus in forensic-medical examinations of infant corpses. Usually, as a rule, pulmonary and gastrointestinal hydrostatic tests are performed. The pulmonary test (dokimasia pulmonalis) is based on the fact of the decrease in the specific weight of the lungs due to the entry of air into the alveoli with the first respiratory movements after birth. The specific weight of the lungs (tissue + blood) is not high and equals according to Krause 1.045-1.056, therefore already a small amount of air is sufficient for them to remain on the surface of the water. The change in the specific weight of the lungs under the influence of the first breaths was known to Galen. It is believed that the physicist Rayger in 1670 first proposed testing the lungs for floating to resolve the question of live birth. But only Schreyer (Saxony) in 1681 began to apply this test for forensic-medical purposes. The technique of it in general outline is as follows: the organs of the neck are isolated, the trachea is tied with a tape, a double ligature is applied to the esophagus at the entrance to the stomach; then the trachea is cut above the ligature and the esophagus between the ligatures, the entire complex of thoracic organs (lungs with trachea, esophagus, heart and thyroid gland) is extracted and lowered into a vessel with water at room temperature for testing for floating; the same is done with each lung, lobes and separate pieces, determining how well the various parts of the lungs hold on to the water and which sink to the bottom of the vessel. In cases where there are signs of putrefaction, the following methods are used: the existing subpleural bubbles filled with gases are punctured, then suspicious pieces of lung tissue are compressed under water; in this case, putrefactive gases are easily removed, and the pieces sink, while air that entered the lungs during breathing is displaced with great difficulty. A positive result of the pulmonary test with certainty indicates that the fetus breathed, provided that certain conditions are excluded, depending on which the lungs acquire the ability to float (markedly expressed putrefaction, artificial introduction of air, prolonged storage in alcohol, freezing). A negative result has less significance. In particular, lungs that contained air can lose it due to impregnation with water and other fluids or from the action of flame. There are also a number of other reasons due to which the lungs may be airless, although the child was born alive. The gastrointestinal hydrostatic test is based on the fact that the gastrointestinal tract of the fetus before birth does not contain air; the latter penetrates there by swallowing or sucking simultaneously with the beginning of respiratory movements, appearing first in the stomach and then in the small and large intestines. Breslau in 1866 proposed, similar to the lungs, to test the gastrointestinal tract for floating. The technique of the test amounts to the following: to prevent the entry of atmospheric air during autopsy, double ligatures are applied in addition to the esophagus also to the exit of the stomach, the small and large intestines at their beginning and end, and then the isolated and separated sections (stomach, small, large intestines) are tested for floating. A positive result of the test supports and supplements the pulmonary test, and sometimes has very valuable independent significance (see Live Birth). In addition, based on the degree of filling and distribution of air in the gastrointestinal tract, one can approximately judge the duration of life of the fetus. In the development of putrefactive gases, as well as in case of suspicion of artificial introduction of air, a positive result of the test is not conclusive. Other tests, proposed at different times, have not justified themselves, and many of them represent only historical interest. In particular, one can point to the ear test (dokimasia auricularis) of Wendt-Wreden (1868), which is based on the assumption that so-called Virchow's mucous tissue, filling the tympanic cavity of the embryo, disappears after the first respiratory movements and the resulting space is penetrated by air inhaled after birth, which can be detected by opening the petrous part of the temporal bone corresponding to the location of the middle ear. However, further research by Lesser and Gnevkovsky showed, 1) that Virchow's mucus in most cases disappears gradually even during intrauterine life and 2) if the space in the tympanic cavity has already formed, as is usually the case at the moment of birth, then air or liquid can indeed penetrate there through the Eustachian tube both during life and after death. These results, as well as the small size of the object (middle ear) to be investigated (Minakov), make this test unsuitable for recognizing live birth. Then there are known the pulmonary blood (Daniel and Ploucquet) and iron (Zalesky) tests, the authors of which proceed from the position that breathing lungs are heavier and contain more iron due to the opening after birth of the small circle of blood circulation and the enhanced inflow of blood into the lungs. With respect to these tests, it should be noted that the determination of the absolute weight of these organs and the amount of iron in them cannot have great significance and above all because in most stillborn children the lungs are already altered by premature respiratory movements and in such cases are especially full of blood. The hepatic blood test of Schaffer (dokimasia hepatica), based on the fact that the blood content and weight of the liver decrease with the first breaths, as well as the tests of Ploucke - lowering of the diaphragm (from IV-V to VI-VII rib), V-atel - increase in the distance between the lower end of the sternum and the spine, Cless-Schlossberger - formation of uric acid infarction in the kidneys, Davydov - peculiarities of blood in the vessels of the thymus gland, have only historical interest. The same must be said about the proposal of Bordas in 1906 to use an X-ray test. Finally, in recent years, Dinits (Brazil) recommends for the same purpose to look for the components of saliva (ptyalin, etc.) in the stomach of the fetus, swallowed with the first respiratory movements. The practical applicability of the salivary test requires confirmation.