Abstract
1) During the fluid therapy of surgical patients, the author found that the serum potassium level of a patient can be largely influenced by the conditions and techniques of separating-cell elements: (dry or wet syringe, test tube silicon coated or not, use of heparin, environmental temperature and length of time after extraction of whole blood, centrifugation etc.)
In order to minimize these errors, an absolute method was established: (1) prepare isotonic and iso-electrolytic heparin solution (Table 2) aseptically, (2) moisten the syringe with this solution, (3) extract the venous blood without any oppression on vein, (4) pour the whole blood into a test tube not silicon-coated, (5) centrifuge for 6-7 min. at 2000, r. p. m, within an hour after the extraction of blood from the patient, (6) remove the plasma into an other tube at once.
2) To verify the clinical usefulness and accuracy of this method, a series of experiments were performed on normal subjects and patients (Fig. 1-6).
3) Normal human plasma potassium level was reexamined by this method. The range, that has been considered to be wider than that of plasma sodium level, was proved to be as narrow as that of sodium.
4) Sixty four surgical patients were administered 20 mEq or more of potassium intravenously in an hour. The plasma potassium level was checked again just after the administration or on the following morning, and it showed no harmful elevation in any cases, even though there were some paradoxical falls of its level.
