Investigations on the Normal Values for the Haemoglobin and Cell Volume in the Small Child.

Abstract

Résumé1. On perusing the literature a considerable lack of agreement in the value given for the Hb. in small healthy children is found.2. The divergencies are partly due to technical errors, and party to physiological errors. National characteristics also seem to play a role.3. In the author's own investigations a physiological lability of the small child's capillary system is demonstrated. Incision with a sharp instrument, where the mechanical irritation of the capillaries is at a minumum, gives relatively low Hb. values, while incision with a blunter instrument causing greater irritation gives relatively high values. The explanation of this is that a contraction of the vessels takes place, the degree of which is regulated by the strength of the irritamentum, which affects the number of red corpuscles, and this finds an excellent analogy in Krogh's experiments on frogs.4. From this it follows that, when dealing with small children, a sharp instrument (cataract knife) must be used in all cases where the blood is taken from the ear and that the incision or puncture should preferably to deep, otherwise quite inconsistent results will be obtained.5. It does not seem to be of any importance which drop of blood is used for the Hb. determination after the incision is made.6. The examination of 85 healthy children, from a fortnight to 2 years old, showed a rapid fall in the Hb. curve from birth, reaching a minimum about the 2nd. or 3rd. month, irrespective of sex. The curve then remained level for the first year at about 80 % (100 % Hb. = 18,5 volumes % oxygen) and only rose again during the 2nd. year.7. The cell volume of the blood in healthy small children, except in the first few months of life, is about the same as that of healthy adult women.8. The relation between the Hb. percentage and the cell volume is denoted by the term Hv. This value signifies the relation between the Hb. of the blood corpuscles and their volume, just as the ordinary index (F. I.) signifies the relation between the Hb. and their number. The small child's physiological chlorosis is demonstrated by means of the Hv. value.9. An increase in Hv. above the physiological limit can be explained by a drying up of the blood.