Oxygen gas (oxygenium) is marketed under compression in steel containers. It is regularly used by inhalation, but has also been employed subcutaneously, intravenously, and intra-abdominally. For inhalation it is passed through water or alcohol in a bottle, and conveyed to the patient by tubing terminating either in a nose-piece to be inserted into the nostril, or in a funnel to be held before the face. It tends to dry the membranes, so if continued for any length of time should be accompanied by the steam from a croup kettle.

Action

The inhalation of oxygen in health has no effect on metabolism, or on the character, frequency, or depth of respiration, but it regularly reduces the rate of the heart and tends to raise arterial pressure.

Fig. 68.

Fig. 68. - Bone-marrow of rabbit after long treatment with benzol. Practically all the blood-forming elements are destroyed (MacCallum).

Kraus reports that in cardiac failure the amount of oxygen taken up by the blood and of Co2 given off is practically unchanged. Leonard Hill says that breathing pure oxygen has little effect on the capillary oxygen tension, and Zuntz and Schumberg produced experimental polypnea and found that the greatly increased amount of oyxgen taken into the lungs caused no alteration in the quantity of oxygen taken into the blood. Yet Starling says that the normal oxygen in the blood and plasma is about 15.6 per cent., and that on breathing pure oxygen for a short time the percentage rises to 19.9 per cent. In cases of cyanosis, however, where the oxygen tension of the alveolar air is low and the Co2 tension in the blood is high, the ability of the blood to take up oxygen is diminished; yet administered oxygen tends to drive out the carbon dioxide. Peabody observed that in pneumonia the oxygen-carrying power of the blood falls as the disease progresses.

Bence found that in cases of cyanosis, oxygen reduced the viscosity of the blood and so favored the circulation; and Stewart noted that, in a case of emphysema, chronic bronchitis, and recurring cyanosis, it increased the blood-flow in the hands from 30 to 70 per cent., though it brought about no especial changes in the respiratory movements. Hill and Flack have noted that after hard boxing-bouts of men not in good training, the inhalation of oxygen reduced the pulse-rate almost to normal, abolished the shallow, hurried breathing, and prevented the stiffness of the muscles which otherwise would have followed on the next day. It has been used in other athletic exercises with similar results, and in mountain-climbing the inhalation of oxygen has proved preventive of "mountain-sickness," which overcomes those not inured to hard work at high altitudes.

Karstner (1916) determined that atmospheres containing 80 to 90 per cent. of oxygen produce in rabbits in twenty-four to forty-eight hours congestion, edema, epithelial degeneration and desquamation, fibrin formation, and finally a fibrinous bronchopneumonia probably of irritative origin. There were no undesirable effects except the local ones in the lungs. It is possible that the local irritation is due in part to the low humidity of the artificial atmosphere. Karstner and Ash (1917) found that atmospheres with up to 60 per cent. of oxygen produced no pathologic changes.

Therapeutics

The net results of the researches give us the impression that while oxygen inhalation has little measurable effect in normal persons, it may have a distinct value in cases of oxygen want, i. e., those cases in which the oxygen tension of the alveolar air is low, or there is hindered passage of oxygen through the alveolar walls, so that the oxygen tension in the blood is below normal. Add to this also the effect of increased oxidation in lessening acidosis, and the revival value of fresh oxygen to the diseased alveolar and capillary tissues, and it would seem that oxygen is a good therapeutic agent in gas-poisoning, pneumonia, edema of the lungs, severe bronchial asthma, heart failure, collapse in general anesthesia, and possibly uremia. Undoubtedly its best effect is seen in conditions with cyanosis. In the night dyspnea of heart cases most striking effects are reported by Mackenzie, who uses a hat box over the head with a hole for the neck, and directs a stream of oxygen into this for fifteen or thirty minutes at bedtime. Haldane says that in carbon monoxide poisoning pure oxygen rapidly drives out the poisonous gas. Pure oxygen should not be used continuously for more than half an hour, but it may be employed continuously to enrich the air which the patient breathes.