Pneumothorax and posture

The sudden entrance of air into the normal healthy pleura often gives rise to a train of grave symptoms. These symptoms have been studied experimentally in dogs. Most of the animals died from the pneumothorax when a large opening was made. Gluck lost all of the dogs he used; Biondi lost 4 of 5; Block, Marcus, Schmidt, Pourrat and Rodet, Tuffier, Murphy, Quenu and Longet, had similar experiences.

In some recent experimental investigations of open pneumothorax I obtained similar results. Many of the dogs either died suddenly as soon as an opening into the pleura was made, or a violent expiratory dyspnea ensued, soon followed by rupture of the mediastinal septum, double pneumothorax, and death. The method of operating on the dogs was the following: The animal was given a hypodermic injection of morphin, and a few hours later was anesthetized with ether; tracheotomy was performed, a cannula inserted, and the administration of ether continued through the cannula. One or more ribs were resected, the intercostal muscles divided, the pleura exposed, and a small opening carefully made in it and gradually enlarged. In a number of the animals, the pressure of the inspired and expired air was roughly measured by allowing the animal to breathe into a large bottle, the tube leading to it from the tracheal cannula being connected by means of a T-tube with a water manometer.

If a small opening (1-5 mm.) is made in the right or left pleura of a dog which is lying on its back, or on its right or left side, the animal will in most instances continue to breathe well, although the amount of inspired and expired air will be less than (about two thirds of) the normal. That such an animal is very sensitive to the slightest influence which disturbs the breathing is shown by the fact that if the animal is deeply under the anesthetic, clamping the trachea for part of a minute will bring on the dyspnea; if the dog is not deeply under the anesthetic, the struggling of the animal or irritation of the cornea, mucous membrane, etc., will bring it on.