[A newly devised continuous catheter flush system for arterial pressure monitoring]

Since Gardner et al. demonstrated a useful continuous catheter flush system in 1970, various systems for blood pressure monitoring have been commercialized. However, some problems have not been solved yet, such as hazard of embolism, infarction, unexpected infusion of large amount of fluid etc.. We have introduced a new type of flush system. which consists of disposable plastic unit with a one-way valve newly developed by us (SAT-route) and a syringe pump (Terumo STC-521). Using this system, only 0.5 ml.hr-1 infusion of heparinized saline was sufficient to prevent the formation of thrombus. Flushing was easily achieved by only pushing the purge button of the pump. As a result, simple, safe and high fidelity pressure monitoring was achieved without much altering the waveform of arterial pressure during flushing. The dynamic frequency response obtained from a square wave test was excellent, with natural frequency of about 40 Hz and damping coefficient of about 0.3. This system is useful especially for perioperative management of small children undergoing cardiac surgery, who require an exquisite infusion therapy and fluid restriction.