Post Operative Blood Chemical Studies.

Abstract

In a series of 50 experiments on dogs operated under ether anesthesia, various blood chemical observations were made at short intervals. The findings were as follows: 1. There is a fall in the CO₂ (van Slyke) generally not more than 10 points. 2. The blood sugar rises slightly at first followed by a moderate fall—15-20 mg. 3. There is a rise in the concentration of the blood as measured by the refractometric index. This is slight and inconstant. 4. Leucocyte, temperature, pulse and blood pressure observations show moderate changes, but in none of our cases were these marked enough to be significant per se.

These observations were made at intervals of 15-30 minutes for 24 hours after the operation and as can be seen they totally fail to explain the profound state of collapse in which any postoperative case lies for about 24 hours.

The positive findings in our series are as follows: 1. A marked tissue thirst is indicated by the findings in the Aldrich intradermal salt test. During the period of postoperative lethargy the wheal is absorbed in approximately half the time that it took in the controls. This tissue dehydration is in striking contrast to the comparatively slight changes in the water content of the blood. 2. The most striking feature found was the enormous changes in the calcium and potassium in the blood. The Ca-K ratio was enormously lowered in every case, in some actually falling below 1. Return to normal had usually taken place by 24 to 36 hours. 3. Parallel with these mineral salt changes there occurs a decisive change in the permeability of the skin as measured by the Blister method. The blistering time is enormously prolonged, in severe cases to twice that noted just before operation.