Pulmonary embolism is a condition frequently encountered in clinical practice. The picture varies from symptoms produced by multiple small emboli lodged in the lung periphery, to symptoms resulting from massive blocking of one or both pulmonary arteries. In the case of small emboli, though severe chest symptoms often result, the patient usually recovers, while in massive blocking it is commonly believed that death ensues either immediately or within a few hours.
That massive pulmonary embolism may occur without disastrous effects on the general circulation was first shown by Lichtheim.1 Two years later Welch2 demonstrated that ligation of the circulation to one entire lung may be accomplished without effect on the systemic blood pressure—an observation confirmed later by Plumier3 and also by Gerhardt.4 Tigerstedt5 corroborated and extended these observations, showing, by means of the stromuhr, that occlusion of half of the pulmonary circulation decreased only slightly
HAGGART GE, WALKER AM. THE PHYSIOLOGY OF PULMONARY EMBOLISM AS DISCLOSED BY QUANTITATIVE OCCLUSION OF THE PULMONARY ARTERY. Arch Surg. 1923;6(3):764-783. doi:10.1001/archsurg.1923.01110190107006