Prophylaxis of Sudden Decompression 895 



Subchapter V 

 SUMMARY 



In summary, sudden decompression, beginning with several 

 atmospheres, brings on symptoms of varying severity depending 

 upon the degree of compression, the speed of the decompression, 

 the animal species, the individuals, and the state of the experi- 

 mental animal at the time. 



These symptoms must be attributed to the escape of nitrogen 

 which had been stored up in excess in the organism, following 

 Dalton's law. 



This gas changes to a free state in the blood vessels, the different 

 organic liquids, and even the interior of the tissues; it may there- 

 fore / according to circumstances, check the pulmonary circulation, 

 soften and cause anemia in certain regions of the nervous centers 

 and especially the lumbar enlargement of the spinal cord, lacerate 

 the tissues, and produce swellings or a more or less extensive 

 emphysema. The severity of the symptoms depends upon both the 

 seat and the extent of these multiple disorders. 



A controlled decompression of 12 minutes per atmosphere is 

 necessary to prevent these symptoms in dogs, when the compres- 

 sion has risen to about 10 atmospheres. 



A recompression, either immediate or following the inhalation 

 of oxygen in case heart gurgles are observed, is the only means 

 of combatting successfully the symptoms of decompression. 



1 At 3 atmospheres, gas escapes in the syringe from the blood drawn. , 



2 Recherches de physiologie et de chimie physiologique. Paris ,1811, p. 55 and 81. 



3 hoc. cit., p. 15 et seq. 



4 Consequently the inhalation of oxygen would be an effective means of checking the effects 

 of the introduction of air into the veins. With this in view, I have made a number of experi- 

 ments quite encouraging for surgeons. 



