302 INOEGANIO AGENTS 



able. Struggling is to be avoided, as far as possible, 

 since it leads to irregular respiration and asphyxia, and 

 causes the ansesthetizer to push the inhalation, strains the 

 heart, and favors cardiac dilatation, with chloroform.. 

 Struggling may be prevented to some extent by giving the 

 anaesthetic well diluted with air at the outsei Asphyxia 

 results also from tetanic fixation, or relaxation of the res- 

 piratory muscles. The signs of asphyxia include cyanotic 

 mucous membranes, muscular twitchings, shallow, feeble, 

 slow and irregular breathing, with long intervals between 

 the respiratory movements, and dilation of the pupils. If 

 death occurs, the heart continues to beat after the breath- 

 ing stops. The condition of the diaphragm during etheriza- 

 tion is an important guide. At first the contractions of the 

 diaphragm are so vigorous that the viscera are forced 

 backward, and the abdominal wall bulges outward during 

 inspiration. As the inhalation is prolonged the diaphragm 

 becomes flaccid and powerless, the respiratory movements 

 are shallow, and the breathing thoracic. The abdominal 

 contents may then be drawn forward during inspiration 

 into the thoracic cavity, so that the abdomen is retracted 

 (Hare). When the latter condition is seen, etherization 

 should be stopped instantly. 



Heart failure occurs more frequently with chloroform, 

 but does occasionally result from the action of ether upon 

 animals with a fatty or otherwise weak heart. Cardiac 

 depression is shown by a weak, irregular and rapid pulse, 

 and pallor of the mucous membranes. The respiratory 

 movements are sustained after the heart ceases to beat in 

 fatal cases. Operations should never be done under 

 chloroform before the patient is fully under the influence 

 of the au aesthetic, as irritation of a sensory nerve caused 

 by even a slight surgical procedure may cause death by 

 reflexly stimulating the vagus and inhibiting the heart. 

 Such an accident is not likely to occur with ether, and 

 minor operations are often done with safety during the 

 first stage of anaesthesia (primary anaesthesia) when con- 



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