On the rate of elimination of chloroform from the blood after anæsthesia

Abstract

In a paper on the rate of assumption of chloroform by the blood, we showed that the percentage of chloroform rises very rapidly to a maximal value. This is the cause of an early danger-point in anæsthesia. Subsequently a rapid fall takes place, followed by a more or less rapid rise towards a maximal value, which is maintained during the rest of anæsthesia. The following remarks will illustrate our conception of the anæsthetic process. The blood at first rapidly becomes charged with chloroform, which is held almost entirely by the red corpuscles. The respiratory centre or centres in the cat become affected quite early, and discharge impulses less frequently than the normal. As a result of this the intake of chloroform is lowered, and consequently the percentage of chloroform in blood falls, either owing to the tissues rapidly storing up the drug at the expense of the blood, or because the elimination of chloroform is as rapid or more rapid than the assumption, or to both these causes. If the first danger-point is safely passed, the respirations improve in frequency and become rapid. It is known that many chemical substances, for instance, the group of alcohols, either or chloroform, which are lethal, primarily act as exciting agents on living cells. Thus those bodies which in a given concentration are lethal for protoplasm, in lower amounts check its activities, but in still less amount, so long as this is above the indifferent point, inversely will act as a stimulus and augment the energy-discharges of protoplasm. In the case of chloroform it would seem that there is an initial stimulating effect which may approach the lethal value, but that if this is not actually attained the stimulating effect, which may approach the lethal value, but that if this is not actually attained the stimulating effect, which was masked, persists as a recognisable after-effect when the first danger-point has been passed. Thereafter the chloroform content of the blood approximates to a maximal value, which is maintained until asphyxia takes place (maximum value).