No abstract

Summary 1. Using the isotope Cr51, the red cell and total blood volumes have been determined in a group of 97 men aged from 55 to 89 years. A description of the method is given. 2. The total blood volume of these geriatric patients was found to be systematically reduced both in relation to body weight and to body surface area. The total blood volume deficit was chiefly dependent on a reduction of the red cell mass. 3. Determination of the blood volume is advocated in all aged patients who are to undergo major surgery. The red cell mass if deficient should be brought up to an approximately normal value for the patient's age and carefully maintained during and after operation.

SummaryExperimental hypothermia in sheep was produced by immersing them in an iced water bath, the body temperature being lowered to 28°–30° C. The animal was anaesthetized with sodium pentobarbitone given intravenously and mechanically ventilated with oxygen during the procedure.There was a significant fall in the serum potassium level and a rise in the hæmatocrit as a result of this cooling. Examination of specimens of skeletal muscle showed that water and sodium had entered the muscle fibre, with a consequent dilution of its potassium. The sulphate space of skeletal muscle was reduced.The changes in muscle suggest either an anoxic effect possibly resulting from the hæmodynamic changes (lowered cardiac output, increased blood viscosity, lowered blood pressure, lowered heart rate and peripheral vasoconstriction) produced by hypothermia, or a direct depression of cell metabolism reducing the energy production necessary to maintain an effective “sodium pump”.All the changes observed were reversed after of the animals were rewarmed.

No abstract