Orville Horwitz

The effect of lipemia upon tissue oxygen tension in man.

The effect of varying levels of lipemia upon tissue oxygen tension has been investigated in human subjects with normal and decreased peripheral blood flow. Oxygen tension of the skin was determined during rapid clearing of lipemia to avoid the difficulties inherent in prolonged study over the several hours of increasing lipemia following a fat meal. Regardless of whether peripheral blood flow was normal or decreased, a mean increase of 21.7 per cent in skin oxygen tension occurred during heparin-induced clearing of plasma turbidity. In addition, skin oxygen tension increased during the spontaneous decline of lipemia in 1 subject. Oxygen tension was not increased after a saline placebo injection during lipemia or following heparin injections in subjects with “clear” fasting serum. The observed increase could not be attributed to changes in blood flow. Skin temperature remained stable during the experiments and the subjects response could not be correlated with skin blood flow as measured by the vasodilatation test. The increase in tissueoxygen tension that occurs during clearing of plasma seems most probably to be due to increased diffusion of oxygen to or from the erythrocytes.

Oxygen Tension of Tissues by the Polarographic Method III. The Effect of Local Heat on the Oxygen Tension of the Skin of Extremities

Simultaneous measurements of skin oxygen tension by polarography and skin temperature by thermocouple were made in patients with peripheral arterial disease and in individuals with normal extremities over a range of skin temperature of 10 to 50 C. The oxygen tension of the skin was found to increase as the skin temperature was raised to about normal body temperature in the ischemic extremity and to significantly higher temperature in the normal extremity. Possible reasons for these changes are discussed.

A modification of the vasodilatation test

Abstract The vasodilatation test, the measurement of blood flow when vasomotor tone is abolished, can be a determining factor in deciding whether or not arterial surgery should be attempted. The purpose of this work is to show the advantages in time, and usually in accuracy, of placing patients in a state of vasodilatation when performing the test. An advantage gained by allowing the feet to be in a slightly dependent position is also demonstrated.

Influence of an Oscillating Bed on Cutaneous Temperature and Oxygen Tension of Ischemic Toes

Measurements of temperature and oxygen tension of the skin demonstrated that treatment with an oscillating bed increases the circulation to ischemic toes. When the angle and duration of the dependent position of the foot of the bed were increased, further increments in circulation resulted.

OXYGEN TENSION OF TISSUES BY THE POLAROGRAPHIC METHOD. VI. EFFECT OF CHANGES IN POSITION ON OXYGEN TENSION OF THE SKIN OF TOES

peripheral arterial occlusion is aggravated by raising the limb and relieved somewhat by lowering the limb. Patients with this condition often complain of foot pain while in bed. This is relieved by getting out of bed. If the head of the bed is raised or special devices are used to lower the leg (1) the pain of the foot is often relieved and the color of the foot improved. Conversely, a case recently came to our attention in which the foot of a patient, who had been confined to bed for a year because of a cerebrovascular accident, became gangrenous only two days after being elevated on two pillows. Elevation of a normal limb decreases the arterial pressure within it, whereas dependency increases the pressure. Measurements of intra-arterial pressure show that the pressure varies directly with the vertical distance from the right atrium to the point of measurement (2). Such changes might be ex

Oxygen Tension of Tissues by the Polarographic Method II. Detection of Right to Left Shunts by Changes in Skin Oxygen Tension Resulting from Inhalation of Oxygen

Normal individuals breathing pure oxygen obtain full saturation of their hemoglobin, whereas those with right to left shunts do not. Oxygen hemoglobin dissociation curves indicate that increases to full oxygen saturation of hemoglobin are accompanied by marked increases of the oxygen tension. When breathing oxygen fails to produce full saturation, relatively little change in oxygen tension occurs. When the cutaneous circulation is rapid, changes in skin oxygen tension have been shown to vary directly with changes in blood oxygen tension. Taking advantage of these facts the authors have described a method of detecting significant right to left shunts by polarographic measurements of skin oxygen tension.