Canadian Journal of Anesthesia, Vol 15, 554-563, Copyright © 1968 by Canadian Anesthesiologists' Society

Dynamic Aspects of Electrolyte and Water Transfers in Human Blood After Morphine

¹ Robert Roessle Klinik, Forschungsgemeinschaft der Deutschen Akademie der Wissenschaften, Berlin-Buch (East Germany)

After the intramuscular injection of clinically used doses of morphine, arterial plasma and corpuscular constituents of human arterial blood were separated under actual conditions by means of a new method. Whole blood as well as red blood cells and plasma were used for dynamic studies of acid-base balance, red blood cell counts, haematocrit, concentrations of anions and cations, the water content of cells and plasma, and the Donnan equilibrium of bicarbonate and chloride.

Under the maximal effect of 12 mg. morphine/m.² body surface we found a small acidification of the arterial blood. The pH of the true plasma decreased on the average from 7.405 to 7.383 and the Paco₂ rose by 1.5 mm. Hg. This slight change of acid-base equilibrium, however, led, under actual conditions, to a loss of Na⁺, K⁺, and water from the red blood cells and a simultaneous gain of potassium and water in plasma. On the other hand Na⁺ was also found to be diminished in plasma. The resulting deficit is discussed.

The chloride and bicarbonate contents of red blood cells increased. This transfer was not fully compensated for and, accordingly, a plasma bicarbonate deficit arose. The Donnan coefficient of chloride increased by 0.018 and that of bicarbonate by 0.019 on the average.

The redistribution of water between the intracellular space and plasma led to a haemodilution which decreased the RBC count, haematocrit, and haemoglobin content.