6 4 



Scientific Proceedings (71). 



38 (1102) 



On continuous insufflation in fowls. A demonstration. 



By A. L. Meyer and S. J. Meltzer. 



[From the Department of Physiology and Pharmacology of the 

 Rockefeller Institute.] 



For many years this laboratory was interested in continuous 

 insufflation which was carried out on mammals. At this meeting 

 we wish to demonstrate apncea produced by continuous insufflation 

 in fowls. As you know, in these animals the bones are connected 

 with the air sacs and the lungs. In this chicken, air is driven 

 through both humeri and it escapes through a tracheal cannula. 

 When the air is driven under sufficient pressure the respiratory 

 movements are entirely abolished; the thorax stands still mostly 

 in an exaggerated state of inspiration. This standstill may be 

 sustained for two hours and longer. By this method the organism 

 is liable to be washed out of its CO2 content more thoroughly 

 than by any other method of artificial respiration or forced res- 

 piration. Nevertheless, the animals appear to be in a good 

 condition with no symptom which could be interpreted as "shock". 

 Furthermore, when the continuous insufflation is interrupted, one 

 of the following conditions may follow, according to the duration 

 of the standstill, the degree of pressure, and to the gas used. 

 Either the inspiratory state may be converted at once into a 

 continuous expiratory standstill (apncea vera), lasting 20 to 50 

 seconds and gradually attaining the amplitude of the original 

 respiratory oscillations; or the state of the inspiratory standstill 

 continues, in a somewhat diminished degree, for many seconds 

 before it is converted, abruptly or gradually, into an expiratory 

 standstill. We shall mention briefly the facts that an admixture 

 of ether to the insufflated air invariably prolongs the expiratory 

 after-effect, and that an admixture of CO2 (3 per cent.) prevents 

 the standstill even during insufflation. 



In fowls the expiration is normally of an active type and the 

 expiratory standstill can only mean that after the interruption of 

 the insufflation the expiratory muscles get temporarily into a state 



