Fig. 3

Gravitation effect on arterial pressures (adapted from [9]). The numbers on the right in mmHg refer to the gravitational potential energy related to the difference between the base of the measuring device relative to the mid-point of the right atrium (dashed line) assuming a 182-cm male. The loss of pressure due to resistance is assumed to be 5 mmHg. When the transducer is set at the level of the right atrium, the mean pressure is 83 mmHg. At the top of the head the pressure would only be 39 mmHg. If the transducer was at the level of the foot, the pressure would be a mean of 171 mmHg