South African Medical Journal

Log in or Register to get access to full text downloads.

Remember me or Register

An electronic apparatus for early detection of changes in red cell content of blood during anaesthesia

A De Waal, JM Hugo, CJC Nel, JM Meyer, JB De Vaal, JF Morrison


An electronic apparatus was developed for anaesthetists to use to detect changes in red cell concentration during surgery. The mechanism is based on the relationship between the red cell content and the electrical conductivity of blood. In a pilot study of 170 blood samples, a correlation coefficient of 0,9806 was obtained between haematocrit and the instrument readings. To evaluate the instrument's performance in practice, and factors that might influence its readings, a series of 10 cases of aortic surgery were investigated. It is concluded that, although changes in electrolyte concentration, pH and temperature do affect the instrument's readings, these are insignificant compared with those of red cell content, and that the device can be used to indicate a drop in red cell concentration.

S Afr Med J 1989; 76: 148-150

AJOL African Journals Online