An experimental inquiry into the pathology and treatment of asphyxia / [John Eric Erichsen].

  • John Eric Erichsen
Date:
1845]
Catalogue details

Licence: Public Domain Mark

Credit: An experimental inquiry into the pathology and treatment of asphyxia / [John Eric Erichsen]. Source: Wellcome Collection.

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    tary, is supported through a comparatively longer period when their fibres are congested even with venous blood, than when emp- tied of that fluid; but that, nevertheless, dark blood is less fa- vourable than arterial to the contractility of muscle. Now in as- phyxia we have both causes, a diminution in the quantity, and an alteration in the quality of the blood, in operation ; the blood that reaches the left cavities, and that is consequently propelled into the coronary arteries, being, after a time, much diminished in quantity, and being also deprived of its normal stimulating qualities by its conversion into venous. Indeed, on referring to the very interest- ing experiments of Dr Reid, on the obstruction that takes place in the systemic capillaries in asphyxia, it will be found that the maximum of the pressure, and consequently of the force of the heart’s contractions, is at about the second minute after the closure of the trachea, and that, after that, the pressure gradually falls, al- though the obstruction continues the same. ‘This is in accordance with what I have likewise observed on repeating and modifying these experiments. I cannot, however, agree with Dr Kay as to the length of time that the heart will continue to contract after the circulation has ceased. He says, ‘that it contracts long after blood has ceased to flow from the coronary veins;” and again, ‘‘its contractions sur- vive the period when it is possible that the coronary arteries can receive the asphyxial blood.” I think that it may fainly be questioned whether this is the case; whether the contractions of the heart continue at all after the circulation through the coronary vessels has ceased. And not only through the coronary, but also through the pulmonary vessels. For it must be borne in mind, that the left cavities of the heart are never found empty in asphyxia ; that although not dis- tended, as the right auricle and yentricle are, yet that they are fre- quently in this disease found to be tolerably full of blood. Coleman states that the relative quantities of blood in the two sides of the heart varies considerably, but that on an average the quantity in the right is to that in the left as 3th to 13th, or as about 33ds to2. Now such a large quantity of blood as this, amounting to nearly two-thirds of that in the right cavities, can certainly not be sup- posed to accumulate in the left side of the heart if the contrac- tions of that organ continue long after the circulation has been brought to a stand. On the contrary, it would Jead to the op- posite inference, or, at all events, prove that the stoppage of the circulation could not have occurred before the cessation of the heart’s action. And this I believe to be the case that the circu- lation is not entirely arrested until the heart has ceased to beat. On taking the average of nearly twenty experiments on asphyx- ia, in which the time that the contractions of the heart continued