Macklin and Macklin 35 y 



time, they are particularly prevalent in time of total war like the present when 

 people are, for instance, buried beneath the debris of bombed buildings. Even 

 if the air has entered from a wound, rather than from an alveolar-base leakage, 

 it may nevertheless be expedient to remove it; and in any event the physician 

 should be aware of its existence whenever present. 



We feel that the discussion of this subject of lung blast should not be closed 

 without favorable comment upon the work which anatomical laboratories, 

 like that of the University of Oxford in England, are doing to advance our 

 knowledge. Zuckerman's™ experimental findings made there have been very 

 helpful. As modern war injures humanity, medical science alleviates and 

 heals. We hope to learn much more about lung-blast lesions in the near future. 



Intratrocheal Anesthesia and Artificial Respiration PIE Cases.— 'Lts^ violent 

 in mode of origin, and more widely distributed, are the PIE cases occurring 

 from artificial alveolar overstrain during the administration of an anesthetic 

 by insufflation, or the induction of artificial respiration, where the pressure 

 within the pulmonic alveoli is too high. This hazard from intratracheal anes- 

 thesia is probably not as great as formerly on account of the safeguards now 

 in use in the improved types of anesthesia machine. The lung must have a con- 

 siderable amount of resistance to alveolar air pressure, otherwise this method 

 of anesthesia could not be used at all. The literature contains accounts of air 

 in the mediastinum or subcutaneous tissues under these circumstances,""** 

 which point indubitably to an initiatory PIE; and of similar meaning is the 

 report of large postrenal blebs of air found in an operation on the kidney." 

 It is not unusual to see descriptions of subcutaneous emphysema following 

 operations in the neck region,*" such as thyroidectomy,^ tracheotomy, or tonsil- 

 lectomy.^** The presence of air is usually ascribed (we think, erroneously, on 

 the whole) to laceration of the airway in the course of the operation, or to 

 nicking the dome of the pleura if the operation was in that region, or to the 

 sucking of air into the wound with inspiration if the operation area involved 

 the mediastinum. It would seem probable that the reason for the frequency 

 of the manifestations of PIE sequelae in operations in the neck region and 

 kidney*" is that insufflation anesthesia is then often employed. Any complicat- 

 ing disease, such as bronchojMieumonia, with atelectasis, ^vould, we think, in- 

 crease the probability of PIE. 



Operations on the open thorax, when artificial respiration and insufflation 

 anesthesia are used, would seem specially liable to set up an air leak. Marcotte 

 and his co-workers*" have recently pointed out the danger of "positive-pressure" 

 anesthesia in such operations, saying that when the chest has been opened and 

 the pressure within the bronchial tree is raised emphysema occurs more 

 readily; and that when emphysema has once made its appearance the pressure 

 required for its further development is somewhat less than that needed to start 

 it in the first place. They issue the warning that such anesthesia may result in 

 serious complications and even death. The results of experimental overinfla- 

 ti(m of the fresh lungs of calves help to explain iliesc (nidings.''' 



