William M. McCord

Blood oxygen changes following intermittent venous occlusion

Abstract The results of this study would seem to indicate that complete vascular occlusion in the presence of a normal circulatory system is followed by a true reactive hyperemia immediately upon release of the compression. The maintenance of complete compression over periods of five to eight minutes was generally followed by a definite rise in the oxygen saturation of the venous blood one minute after its release, and in most cases the elevation was maintained at the end of three minutes. It may therefore be assumed that the reactive hyperemia produced by this type of occlusion brings about a more rapid flow of blood through the extremity, as well as a marked increase in the volume of the flow. Intermittent venous occlusion, on the other hand, even in the presence of a normal circulatory system, is usually followed by a lowering of the oxygen saturation of the venous blood at one minute as well as three minutes after the release of the occlusion. This would seem to indicate that under the circumstances of this test (with a pressure varying from 60 to 80 mm. Hg, and with a ratio of compression and release of 2:2 and 2:1) a true reactive hyperemia is not produced. Any favorable effects claimed for this type of therapy must therefore result not so much from an increase in the rate or the volume of the blood flow as from some chemical changes produced in the tissues incident to the venous congestion and the changes produced by the increased venous pressure. It might be said in conclusion that these findings bear out those of Allen and McKechnie 5 in their study of the effect of intermittent venous occlusion on the skin temperature under controlled circumstances. In nineteen patients (nine normal subjects, and ten with hypertension, arthritis, and peripheral vascular disease) they found no evidence that any significant or consistent vasodilatation resulted from the procedure.

Serial Bone Marrow Studies in Pernicious Anemia. III. Occurrence of Protoporphyrin in Human Bone Marrow

Summary The occurrence of protoporphyrin was studied in 133 sternal bone marrow specimens. Protoporphyrin was :mostregularly present in marrow samples containing predominately normoblastic young red blood cells. Ninety-six sternal bone marrow specimens from 12 patients with Addisonian pernicious anemia before and after liver extract injection were obtained by serial sternal punctures at 24-hr intervals. The appearance of protoporphyrin was coincidental with the increase of immature red cells of normoblastic type in the marrow.

Viscosity studies of erythrocytes from persons with sickle cell disease.

Summary A viscosimetric method is described for the study of the sickling tendency of red cells from subjects with sickle cell disease. This method does not differentiate between sickle cell anemia and sickle cell trait. Data are compared with observations of other investigators.

Correlation of Rf Values and Distribution Coefficients in Amino Acid Paper Chromatography

Summary The distribution coefficients of amino acids between the 2 phases of a phenol-water mixture have been determined at various H+ concentrations, and at temperatures of 20°, 25°, and 30°C. Rf values calculated from each of these distribution coefficients have been correlated by statistical methods with corresponding Rf values as measured by paper chromatography and a significant relationship has been demonstrated.

Sickle cell anemia, blood viscosity and sodium tetrathionate.

A decrease in blood viscosity, caused by the intravenous injection of sodium tetrathionate, has been reported by Theis and Freeland (1). This decrease apparently is accompanied by an increase in oxygen saturation. The pathogenesis of sickle cell anemia, while yet obscure, seems to be associated, according to Pauling, et al. (2) with an abnormality in the structure of the hemoglobin molecule. This abnormality is reflected by changes in the shape of the erythrocyte, under reduced oxygen tension, which cause an increase in blood viscosity, thus setting up a vicious cycle, which may terminate in a state of crisis. The purpose of this investigation was to determine whether sodium tetrathionate would break the above mentioned vicious cycle by decreasing the viscosity of the blood of sickle cell anemia patients. It has been shown(3) that by using an Ostwald type viscosimeter the relative viscosity of blood samples, after exposure to oxygen and carbon dioxide, can be expressed in seconds and that the difference, expressed in seconds, should be a fairly accurate measure of the viscousness of the blood of a patient with sickle cell anemia in crises. Simple measurements of absolute viscosity were deemed unsatisfactory in that changes in protein concentration or water balance, hemolysis or peptization of serum proteins would make the evaluation of results difficult. The use of the “difference value” simply uses the oxygenated blood as a control and thus eliminates, to a great extent, factors other than those pertaining to the erythrocyte itself. Twelve patients, with definitely proved sickle cell anemia in crisis, or seemingly approaching crisis, were given sodium tetrathionate† by vein. Relative viscosity under carbon dioxide and oxygen, hemoglobin, and serum protein determinations were made, before and after the drug, upon a number of successive days.

Blood Oxygen Changes in Intermittent Claudication

Conclusions Determinations of the oxygen saturation of the venous blood reveal a lower oxygen content in a series of normal individuals after exercise than in a series of arteriosclerotic subjects with intermittent claudication. If intermittent claudication in arteriosclerotic subjects is produced by a tissue anoxemia, it cannot be demonstrated by determinations of the oxygen content of the superficial and deep venous blood.