756 ARTIFICIAL RESPIRATION. 



supplied to it through the placenta. All factors that interfere with this 

 supply, therefore especially compression of the umbilical vessels and per- 

 sistent uterine contractions, cause reduction of oxygen and increase of 

 carbon dioxid in the blood, and in consequence a state of the blood 

 results that stimulates the respiratory center, and with this the im- 

 pulse for the respiratory movement itself. Thus the fetus within 

 the unopened membranes may be stimulated to respiratory move- 

 ments. If the factors interrupting the gaseous interchange persist, 

 the stimulated respiration becomes dyspneic, and finally death occurs 

 from asphyxia. If the venosity of the fetal blood develops gradually, 

 as, for example, in case of slow, quiet death of the mother, the medulla 

 oblongata of the fetus may die gradually without the development of 

 respiratory movement, without, therefore, the interruption of fetal 

 apnea. This is a paralysis due to slowly insidious irritation. 



Accordingly, the respiratory movement is excited in the medulla directly by 

 the dyspneic state of the blood. Asphyxia of the mother may have the same 

 effect as compression of the umbilical vessels. In such an event the maternal 

 blood rapidly becomes venous and abstracts the oxygen from the blood of the 

 fetus, in consequence of which the death of the latter is accelerated. If the mother 

 has been rapidly asphyxiated by carbon monoxid the life of the fetus may be 

 prolonged, as the carbon-monoxid hemoglobin of the maternal blood naturally 

 can remove no oxygen from the fetal blood. When the poisoning takes place 

 slowly carbon monoxid also passes over into the fetal blood. 



In many instances, especially when, after persistent uterine contrac- 

 tions, the irritability of the respiratory center is already greatly en- 

 feebled, the dyspneic state of the blood, which becomes even more 

 marked after birth, is not in itself sufficient to stimulate the respiratory 

 movements in rhythmic and typical form. For this purpose there is 

 required in addition irritation of the external integument, for example 

 through lowering of the temperature on evaporation of the amnial liquor 

 in the air. If, also, in consequence of the first movements that follow, 

 air has entered the respiratory passages, the air may exert a stimulating 

 influence upon the pulmonary branches of the vagus. 



According to the observations of v. Preuschen the stimulation of the respira- 

 tory center through the nerves of the external integument is more effective than 

 that through the branches of the vagus to the respiratory organ. Also in animals 

 that have been made apneic by means of vigorous artificial respiration, this ob- 

 server noted active respiratory movements setting in after application of cutaneous 

 irritants, such as a douche of cold water. Mechanical cutaneous irritants, such as 

 friction or slapping, support advantageously the stimulation of the respiratory 

 center, as does also douching with cold water or irritation with the electric brush. 

 the placental circulation is completely intact, cutaneous irritation, however, 

 alone induces no respiratory movements. 



Artificial Respiratory Movements in the Asphyxiated. In man, it is customary, 

 for purposes of resuscitation in the presence of asphyxia, to practise artificial 

 respiratory movements. The subjects under such circumstances have usually 

 been suffocated, strangulated or drowned, or are children born in a state of as- 

 phyxia (intrauterine suffocation). The first duty in the presence of such a con- 

 lition is the removal from the air-passages of foreign matters, such as mucus 



lematous fluid in the newborn or the asphyxiated, water in the case of the 



drowned by, lowering the head; in desperate cases, even after tracheotomy, by 



suction through an elastic catheter introduced into the opening. Next, artificial 



respiration must be undertaken at once. Various devices and methods have been 



Ascribed for this purpose, but these cannot be considered in detail here. Alternate 



dilatation and contraction of the chest, and thereby gaseous interchange, can be 



ed by rhythmic compression of the thorax by application of the flat hand. 



I he asphyxiated individual is placed in the dorsal decubitus, the vertebral column 



>emg flexed backward (with the aid of suitable support) as far as possible The 



