Carbon dioxide transport in the body—a simple electrical analogue

An electrical analogue of the system for CO₂ transport in the human body has been developed using analogue rather than digital techniques. Outputs show the mean value and oscillating component of mixed venous and arterial pCO₂ as a function of time. The effect of varying the parameters which determine CO₂ levels can be observed in quasi-real time without any delays for computation. The behaviour of the analogue is discussed and its output is compared with corresponding measurements on real subjects. The analogue provides a sufficiently realistic model for use as a demonstration or as a ‘thinking aid’ when considering possible control mechanisms for CO₂ regulation.