Measurement of Blood Pressure

1. Direct Measurement

The most accurate way to measure blood pressure is to insert a cannula into an artery and connect this directly to a pressure transducer. In fact the first reported measurement was by Stephen Hales who cannulated the carotid artery of a conscious, restrained horse and measured the height that the blood rose in a glass tube inserted into the artery.

Direct measurement, using a pressure transducer attached to an arterial cannula, may be used for patients in intensive care where the blood pressure needs to be monitored continuously.