Arterial pressure / by G. A. Gibson.

  • Gibson George Alexander, 1854-1913.
Date:
1911
Catalogue details

Licence: In copyright

Credit: Arterial pressure / by G. A. Gibson. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    pressure of 95 became highly tortuous when the pressure rose to 200 mm. Hg. Turning to the heart, we find in acute pericarditis an affection with a great tendency to bring about a lowering of arterial pressure, through its weakening effect upon the myocardium, and it is one of the affections in which a favourable or an unfavourable prognosis may be reached, according as there is little or consider- able lowering of the pressure. All the recent cases of pericarditis which have crossed my path have made excellent recoveries, and on looking over their records, the striking feature is that in no case was the arterial pressure below 125 mm. Hg. When the pericardium is distended with fluid, as the result of an acute attack, the arterial pressure falls to a level which is alarming, and which is one of the surest indications of the necessity for active intervention. In the case of acute endocarditis there is like- wise a liability to a fall of arterial pressure, and here, again, the prognostic significance of the arterial pressure cannot be over- estimated. Amongst the various valvular lesions there is an immense series of different pressure results. In most of them, until fatal cardiac failure steps in, there is but little interference with arterial pressure, so w'onderful are the powers of compensa- tion possessed by the circulatory system. In aortic disease there is a most striking instance of remarkable divergence between the systolic and the diastolic pressure. This has been already referred to in the introductory remarks upon the co-efficient of pressure and the efficiency of the heart. It is very common in aortic disease to find a systolic pressure of 170 or 180, while the diastolic pressure may only be from 70 to 80. Even greater variations of pulse pressure have been recorded. Another interesting point in aortic disease, with insufficiency, is that the difference between the arterial pressure in the arms and legs is much greater than in health. To this point attention has been particularly directed by Hill and Hare. It has been suggested by the former that the condition is a reflex one, intended by Nature to prevent cerebral anaemia. Other valvular diseases produce comparatively little alteration upon the arterial pressure, except in so far as they bring about alterations in the efficiency of the myocardium. Diseases of the myocardium yield widely different readings; in fact, the results entirely depend upon whether the myocardial troubles are due to primary alterations in the heart muscle or are secondary to disease elsewhere. In such affections as myocarditis, following upon diphtheria or other