On consumption and on certain diseases of the lungs and pleuræ / by R. Douglas Powell.

  • Sir Richard Powell, 1st Baronet
Date:
1878
Catalogue details

Licence: Public Domain Mark

Credit: On consumption and on certain diseases of the lungs and pleuræ / by R. Douglas Powell. Source: Wellcome Collection.

Provider: This material has been provided by the Harvey Cushing/John Hay Whitney Medical Library at Yale University, through the Medical Heritage Library. The original may be consulted at the Harvey Cushing/John Hay Whitney Medical Library at Yale University.

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    These are the obvious effects of pressure similar to those of excessive fluid effusion into one pleura. The illustration in the schema of what happens on the healthy side as the fluid advances, how the thoracic walls expand to the limit of their resilience making way for the heart, and reliev- ing it from pressure to the latest moment, is interesting, and a true diagram of what occurs in nature. The late appear- ance of any increase in the comparative measurement of the chest on the side of the effusion is thus accounted for. There is at first an increase in the total circumference, and only in extreme effusions is there comparative increase on the affected side. Increase of measurement on the affected side, there- fore is, other causes being excluded, an evidence of positive intra-thoracic pressure. Bulging downwards of the diaphragm has the same significance. Displacement of heart per se is not significant of pressure. b. Pneumothorax. The effect of admitting air into the pleura is somewhat different from that of admitting fluid, but the difference is one merely of time and degree. In our schema we can imitate pneumothorax either by thrusting a needle through trachea tube D', and puncturing the bag, or what is more convenient, by opening stop-cock B'. The result will be instant collapse of bag C to c, instant fall of column I' K' to the level, immediate displacement of the mediastinum, E F, to position of dotted line, with slight contraction of C, and slight falling of I K. I have already enlarged upon the clinical phenomena of pneumothorax, (page 130 et seq.,) they are identical with those illustrated in the schema. Although theoretically, we might conceive air to be effused into the pleura as gradually as fluid, yet practi- cally, this is rarely the case. The escape of air, even through a small opening, is so rapid that its consequences may be rightly described as sudden. Hence in pneumothorax, as we have seen, displacement of the heart is instantaneous, and the diaphragm, no longer supported by the traction of the
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