Some considerations in regard to acute obstructive diseases of the lungs / by Andrew H. Smith.

  • Smith, Andrew H. (Andrew Heermance), 1837-1910.
Date:
1890
Catalogue details

Licence: Public Domain Mark

Credit: Some considerations in regard to acute obstructive diseases of the lungs / by Andrew H. Smith. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    right htdiXt in its effort to unload the venous circulation through the obstructed vessels of the lungs. Now, while we cannot place our finger upon the pulmonary artery, we can obtain nearly the same information by applying the stethoscope over the pulmonary valve. Owing to ana- tomical conditions which it is not necessary to describe, it is entirely practicable to separate the pulmonary valve-sounds from the aortic, and by means of auscultation to study the peculiarities of the former as indicating the condition of the pulmonary circulation. Unfortunately, however, in some cases the valve-sound is masked by bronchial rales, so that it may be impossible to appreciate it accurately. But even in the most rapid breathing there are brief intervals during which the practised ear may nearly always gather the required information. Now, if we note carefully the sound of the pulmonary valve in, for example, a case of pneumonia, we shall find that at the outset, while the right ventricle is still in vigorous action, this sound is especially clear and sharp, indicating a quick and strong recoil of the pulmonary artery following the ventricular systole. This sharp recoil is due to unusual distention of the vessel, and this in turn is due to the resistance which the blood meets in passing through the lungs. If the case is to terminate favorably this accentuation of the pulmonary sound will probably continue through the whole course of the disease, becoming less marked as the obstruction in the lung decreases. But in cases of increasing severity, and with an unfavorable tendency, a time soon comes when not only this accentuation is lost, but the normal intensity of the valve-sound is lessened, the sound becoming weaker and weaker, until it ceases to be heard. This means, not that the obstruc- tion has become less, but simply that the muscular power of the right ventricle has become exhausted with the labor exacted of it. The blood is no longer driven through the artery with sufficient force to distend it, and there is not enough recoil to bring the valve-cusps together with an audible sound. When this point is reached, the end is not far off. The weakening of the right heart favors still greater pulmonary