A new optical transducer for arterial pressure measurement

A new optical pressure transducer system (Viggo) has been assessed and compared with a standard P10 transducer (Spectramed) using a similar 20-gauge cannula, both in vitro in terms of linearity and frequency response and in vivo using an animal model. The linearity of the transducers was comparable; the resonant frequencies were 106 Hz and 75 Hz, respectively. However, the resonant frequency of the complete Spectramed system including 150-cm tubing was 11 Hz. The frequencies at which the output amplitude error exceeded 10% of the initial amplitude for the Viggo and for P10 with and without 150-cm tubing were 32 Hz, 24 Hz and 4 Hz, respectively. The principal advantage of the new transducer is that it is sufficiently compact to be mounted directly in the cannula at the wrist, so obviating the use of connecting tubing between the transducer and the cannula.