A clinical monitoring system has been developed using a computer and an analogue-to-digital converter connected to standard fluid pressure and transcutaneous blood gas measurement equipment. It will collect and store information from up to four channels as trend data points, as waveform samples or as both. These monitoring and waveform recording roles have not been combined before in comparable systems. The trend data from any of the channels may be displayed on the computer screen as either a short-term (up to 3 h) or long-term (up to 99 h) graph as required. All this data may be retrieved from disk at the conclusion of monitoring to produce hard-copy for patient records. In particular the pressure waveforms have been used as the basis for subsequent research work.