The role of tracheostomy in ICU

sensors are the closest available systems to this ideal. For the more commonly used manometric systems, the total measuring chain, consisting of catheter or cannula, tubing, stopcocks and transducer, has a much lower resonant frequency, and damping is therefore vital for increasing accuracy. Optimally damped systems can accurately reproduce frequencies up to 67% of the resonant frequency. An optimally damped manometric transducer system with a resonant frequency of 36 Hz or more should therefore be able to reproduce the shape of the arterial pressure waveform accurately up to a heart rate of 180 beats/min. All manometric pressure monitoring systems introduce a degree of dynamic distortion into the pressure waveform. Some manufacturers produce complete pressure measurement systems where the performance of the entire measurement pathway has been measured dynamically using the GabarithTM test. The accuracy of these systems is guaranteed to lie within tightly defined limits. Fourier analysis of the arterial pressure waveform