An experimental inquiry into the pathology and treatment of asphyxia ... To which the Royal Humane Society awarded the Fothergillian Gold Medal / [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 ... To which the Royal Humane Society awarded the Fothergillian Gold Medal / [John Eric Erichsen]. Source: Wellcome Collection.

    11/64 page 9
    by direct experiment upon animals, that, on ligaturing the larger arte- rial trunks, the limbs from which the supply was thus cut off were found to be much weakened, and indeed paralysed in their muscular power. It is also a fact familiar to all practical surgeons, that, after the ligature of the main artery of a limb, as the femoral or axillary, for instance, voluntary motion will be lost in the part which is thus de¬ prived of its blood; and in these cases it is often many weeks before the power of moving the extremity is regained. That the same is the case in the heart I have already attempted to shew by some ex¬ periments, the details of which were read before the British Associa¬ tion in 1842, and which were published in the Medical Gazette of the same year. From these it would appear, first, That the arrest of the coronary circulation produces a speedy cessation of the heart’s action, though respiration be actively carried on; and, secondly, That the presence of venous blood in the fibres of the heart serves to maintain the contractions of that organ for a longer period than when its tissue is entirely deprived of blood. Dr. Kay had previously satisfactorily and incontestably ascertained that the contractile power of muscles, involuntary as well as voluntary, is supported through a comparatively longer period when their fibres are congested even with venous blood, than when emptied of that fluid; but that, nevertheless, dark blood is less favourable than arterial to the contractility of muscle. Now in asphyxia 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 con¬ version into venous. Indeed, on referring to the very interesting 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, although 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 survive the period when it is possible that the coronary arteries can receive the asphyxial blood.” I think that it may fairly be questioned whether this is the case ; whether the contractions of the heart continue at all after the circula¬ tion 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 distended, as the right auricle B
    digitised image 1
    digitised image 2
    digitised image 3