XI, B, 1 de la Paz and Garcia: Use of Apomorphine 55 



RESPIRATORY PRESSURE AND CONDITION OF THE GLOTTIS DURING 



VOMITING 



According to the manner of action ascribed to apomorphine 

 as an agent to remove foreign bodies from the respiratory- 

 passages, it must cause a rise of the intrapulmonic pressure 

 and opening of the glottis, or, in other words, a forced expiration 

 during the act of vomiting. The determination, therefore, of 

 the intrapulmonic pressure and the condition of the glottis 

 during emesis should furnish important information relative 

 to the mode of action of apomorphine under consideration. 



The intrapulmonic pressure was taken from a tracheal can- 

 nula and recorded as follows: One limb of a Y-tube was con- 

 nected with the tracheal cannula by means of rubber tubing ; the 

 second limb was connected with a mercury manometer whose float 

 was adjusted to write on a slow drum; and to the third limb 

 was attached a short piece of rubber tubing so arranged that it 

 could be readily closed or opened when desired. Plate I, fig. 1, is 

 a tracing taken during emesis produced by apomorphine when the 

 third limb of the Y-tube was closed before the beginning of one of 

 the deep inspirations at the commencement of vomiting. The 

 pressure oscillated about the zero line, but in the expulsion time — 

 the time which elapses from the beginning of the convulsive 

 contraction of the abdominal wall to the appearance of vomitus 

 in the mouth — it reached a high level. When the pressure was 

 taken from the perpendicular limb of a T-tube whose horizontal 

 limb was inserted through the median cervical line into the 

 trachea so that it did not interfere with the mechanism of the 

 glottis, the curves obtained were almost identical with Plate I, 

 fig. 1. The curves obtained in this way are illustrated in Plate 

 II, fig. 2. The pressure in this case sank much lower below the 

 zero line during the deep inspirations, and as the rise of pressure 

 was relatively lower, the latter might have been simple rebounds 

 of the mercury in the manometer and not actual increased 

 pressure. This could not, however, be the chief cause ; otherwise 

 the waves should progressively diminish. This they did not do. 

 From the standpoint of the mechanism of vomiting, attention 

 is called to the late appearance of the vomitus in the mouth 

 in relation to the beginning of the rise of intrapulmonic pressure. 

 The time relation of these two events seems to indicate that the 

 oesophagus is probably not subjected to a negative pressure 



